1. science
2. medicine
3. surgery

The authors of abstracts marked *** have indicated a financial interest.
HO1 IMPACT OF EXTRACORPOREAL SHOCKWAVE THERAPY ON TOOTH MOBILITY
IN ADULT ORTHODONTIC PATIENTS: A RANDOMIZED PLACEBO-CONTROLLED
CLINICAL TRIAL
Frank Falkensammer1, Xiaohui Rausch-Fan1,2, Wolfgang Schaden3, Danijel Kivaranovic4,
Josef Freudenthaler1, Departments of 1Orthodontics and 2Oral Biology. University Clinic of
Dentistry Vienna, 3Department of Traumatology, AUVA Trauma Center and Ludwig
Boltzmann Institute for Experimental and Clinical Traumatology, Vienna and 4Department of:
Medical Statistics, Medical University of Vienna, Austria
AIMS: This randomised controlled clinical trial investigated the effect of non-invasive
extracorporeal shockwaves therapy on tooth mobility in orthodontic patients after active
treatment.
SUBJECTS AND METHOD: Seventy-two adult patients were included in the study.
Immediately after active orthodontic treatment, the patients were assigned to a treatment or
a placebo group based on block randomization. The orthodontic patients were required to be
otherwise healthy. The region of interest was the anterior portion of the mandible. The
treatment group received single shockwave treatment of 1000 impulses while the placebo
group was treated with an acoustic sham. Tooth mobility was evaluated over a period of 6
months using a Periotest and manual testing. Pocket probing depths, bleeding on probing,
and the irregularity index were also assessed.
RESULTS: Tooth mobility reduced significantly over 6 months in both groups, but
shockwaves resulted in a significantly more rapid reduction on manual testing. Probing depth
was significantly reduced while the irregularity index remained stable. Shockwaves were
found to significantly reduce bleeding on probing.
CONCLUSION: The mobility of teeth aligned by orthodontic treatment reduces over time.
Shockwave treatment appears to reduce tooth mobility more rapidly and have an antiinflammatory effect.
HO2 GENETIC ASSOCIATION OF ARHGAP21 GENE VARIANT WITH MANDIBULAR
PROGNATHISM
Maddalena Vitale1, Letizia Perillo1, Angela Monsurrò1, Annalaura Torella2, Vincenzo Nigro2,
Departments of 1Orthodontics and 2Biochemistry, Biophysics and General Pathology,
Second University of Naples, Italy
AIMS: Mandibular prognathism (MP) is a phenotype associated with a dento-skeletal Class
III malocclusion. To date, this genetic trait has been investigated using linkage analysis or
association studies in pooled families. Here, for the first time, next-generation sequencing
was used in a single family with a large number of MP-members to identify MP-related
candidate genes.
SUBJECTS AND METHOD: A six-generation kindred with autosomal dominant MP was
recruited. Cephalometric procedures identified MP-members. In five MP subjects, whole
exome sequencing was performed.
RESULTS: Five missense gene variants (BMP3, ANXA2, FLNB, HOXA2 and ARHGAP21)
MP associated were selected and genotyped in most other family members. In this family,
where MP seemed to consist of two distinct genetic branches, the Gly1121Ser variant in the
ARHGAP21 gene was shared by all MP individuals in the larger branch with nearly complete
penetrance. This variant, rare in the Caucasian population, is predicted as damaging by all
bioinformatic algorithms.
CONCLUSION: ARHGAP21 protein strengthens cell-cell adhesions, and may be regulated
by bone morphogenetic factors, thus influencing mandibular growth.
HO3 A THREE-DIMENSIONAL POPULATION-BASED HERITABILITY STUDY OF
FACIAL MORPHOLOGICAL TRAITS IN UK FEMALE TWINS
Jelena Djordjevic, Alexei Zhurov, Stephen Richmond, Department of Applied Clinical
Research and Public Health, Cardiff University, U.K.
AIMS: Although heritability of facial morphology sparks interest from different disciplines, the
exact genetic determinants of normal facial variation are largely unknown. The aim of this
three-dimensional (3D) population-based study was to evaluate heritability of facial
morphological traits by comparing faces of monozygotic (MZ) and dizygotic (DZ) twins.
MATERIALS AND METHOD: 3D facial images of 1380 female twins were selected from the
database of the Twins UK Registry. Two types of analysis were performed: (i) based on
principal components (PCs) extracted from the unscaled (19) and scaled (23) landmark
configurations of 37 manually identified landmarks; (ii) based on all possible 1275 linear
distances for 51 landmarks (after automatically introducing an additional 14 mid-points).
Correlation coefficients were calculated for all PCs and linear distances for MZ (rMZ) and DZ
(rDZ) twins. In adddition, rMZ-2rDZ was calculated to assess possible non-additive
(rMZ>2rDZ) or common environmental effects (rMZ<2rDZ) on the traits.
RESULTS: Narrow-sense heritability ranged from 12 to 77 per cent for PCs and from 13 to
86 per cent for linear distances. Facial size, inter-ocular distance, prominence of the nasal
root, nose width and upper lip prominence demonstrated heritability above 70 per cent. A
non-additive (dominant) genetic effect was found for two PCs (related to nose width and the
prominence of the nasal root) and 11 distances. A common environmental effect was shown
for three PCs (related to the vertical position of the zygomatic arch and the angle of the
mandible) and 50 distances.
CONCLUSION: The majority of the facial parameters showed strong evidence of heritability.
Additive genetic effects can explain the vast majority of the influence of genes in the shaping
of facial phenotype. For certain traits, there is evidence that phenotypic variation can be
partly explained by the non-additive (dominant) effects of genes, whereas, for some, the
common environment may also play a role. This research provides a comprehensive
calculation of facial parameters which can be applied in future genome-wide association
studies.
OP1 TREATMENT OF MAXILLARY RETROGNATHISM WITH MAXILLARY TRACTION:
FACEMASK COMPARED WITH TRACTION ON BONE ANCHORS
Miha Bobic1, Paolo Cattaneo1, Jytte Buhl2, Thomas Klit Pedersen1, 1Section of Orthodontics,
Aarhus University and 2Department of Maxillofacial Surgery, Aarhus University Hospital,
Denmark
AIMS: To compare two treatment protocols for maxillary protraction: elastic traction on bone
anchors and elastic traction on a facemask.
SUBJECTS AND METHOD: In a retrospective study, 21 facemask (FM) patients [10 males,
11 females with a mean age of 9.03 ± 1.00 years before protraction treatment (T1) and 9,86
± 0,97 years after protraction (T2)] and 15 bone anchored maxillary protraction (BAMP)
patients (9 males. 6 females with a mean age of 13.00 ± 0.88 years at T1 and 14.27 ±1.15
years at T2) were age matched with two control groups: control FM consisted of 21 subjects,
10 males and 11 females with a mean age of 8.53 ± 0.66 years at T1 and 9.58 ± 0.79 years
at T2 and control BAMP comprised 22 subjects, 11 males and 11 females with a mean age
of 12.72 ± 0.68 years at T1 and 13.88 ± 0.76 years at T2. . The treatment groups consisted
of patients treated at Aarhus Dental School and Aarhus University Hospital. The control
groups were collected from historical records of several growth studies. Radiographic
registrations were taken at T1 and T2. Conventional or cone beam computer tomographicgenerated lateral cephalograms, were scaled and used for analysis. A coordinate system
based on a stable basicranial line (SBL) was used as a reference for measurements of
horizontal and vertical movements of selected landmarks. Changes occurring between T1
and T2 were compared within the same group, between treatment and control, and between
BAMP and FM.
RESULTS: Treatment and growth caused the maxilla to move anteriorly. In the FM group,
point A moved 2.2 mm anteriorly and 1.4 mm downward, while in the BAMP group 2.9 mm
and 1.7 mm correspondingly. Both treatments showed a significant increase in horizontal
movement compared to controls (P < 0.001). BAMP produced significantly more anterior
movement than FM (P = 0.03). The differences in vertical movement of point A between
treatment groups were non-significant. Point B moved 0.6 mm backwards and 1.7 mm
downwards with FM. The equivalent movements with BAMP were 2.6 mm anteriorly and 1.2
mm downwards. Restricted anterior movement of point B was seen in the FM group in
contrast to BAMP and controls. The mandibular line showed posterior rotation in FM (1°) and
anterior rotation with BAMP (–1°; P < 0.001).
CONCLUSION: Both FH and BAMP are effective in protracting the maxilla. BAMP produces
statistically significantly more protraction compared to FM. FM is more successful in
restricting horizontal movement of point B but causes more posterior rotation of the mandible
while BAMP causes anterior rotation. Comparing anterior vertical face height, no significant
changes were seen in either of the groups. In this context, the difference in age of the two
treatment groups must be emphasized. The results of the study do not support evidence to
warrant abandoning early FM treatment in favour of BAMP at a later age.
OP2 DETERMINATION OF AGE AT PUBERTAL ONSET BASED ON ANNUAL HEIGHT
MEASUREMENTS
Johan Karlberg1, Urban Hagg2, 1Clinical Trial Magnifier Ltd., Hong Kong and 2Department of
Dentistry, University of Hong Kong, China
AIMS: To evaluate a method of determining the age at puberty onset based on annual
height measurements alone. and to relate the age at onset of puberty to the age at the
appearance of secondary gender characteristics.
SUBJECTS AND METHOD: A Swedish longitudinal growth study comprising 69 girls and 91
boys who were followed-up from birth to maturity (18 years) with annual height
measurements and other measurements such as secondary gender characteristics.
Evaluation of the onset of puberty for each child was determined using a computerized
growth monitoring program based on the so-called Infancy-Childhood-Puberty growth model.
The onset of puberty was evaluated annually from six years without knowing the subsequent
path of growth (blinded evaluation) for each child of the Swedish longitudinal growth study.
The data set also included information about secondary gender characteristics.
RESULTS: The age at which pubertal onset was identified was on average 11.4 years (SD
1.0) in girls and 13.2 years (SD 1.0) in boys. The estimated age at onset of puberty was on
average 10.1 years (SD 1.0) in girls and 12.1 years (SD 1.0) in boys. The mean individual
difference between the age at which pubertal onset was identified and the estimated age at
onset of puberty was 1.3 years (SD 0.3) in girls and 1.1 years (SD 0.4) in boys. Secondary
gender characteristics showed that the vast majority of the children were in the pre-pubertal
stage when the pubertal onset was identified.
CONCLUSION: The method presented is highly effective, accurate and simple in detecting
the onset of puberty in an individual child in the clinic.
OP3 EARLY ORTHODONTIC AND SURGICAL TREATMENT OFIN PATIENTS WITH
HEMIFACIAL MICROSOMIA (GOLDENHAR SYNDROME): PROCEDURES AND TIMING
Noah Cohen1, Erica Cohen1, Joseph Felix Giordanetto1, Jacque-Marie Mercier2, Amnon
Cohen1, 1Department of Pediatrics, Inter-Regional Center for Rare Diseases, San Paolo
Hospital, Savona, Italy and 2Service de chirurgie maxillo-faciale et stomatologie - chirurgie
plastique pédiatrique, CHU de Nantes, France
AIMS: To propose an algorithm regarding the timing and types of orthodontic and surgical
treatment to be followed in patients with hemifacial microsomia (HFM), based on the severity
of craniofacial deformities. This is the result of both the centre’s experience and a
comprehensive review of the literature.
SUBJECTS AND METHOD: Fifty one patients with HFM (19 females; 32 males, 16.7 ±
7.7 years of age, range 10-47 years) were analyzed and divided into three groups, based on
the type of mandibular hypoplasia (Type 1, 2a, 2b and 3 according to the Kaban
classification).
RESULTS: Group 1: 25 patients (16 males; 9 females) with type 1 mandibular hypoplasia
treated with functional and orthodontic fixed appliances. Group 2: 11 patients (7 males; 4
females) with type 2a mandibular hypoplasia treated with an orthodontic activator and
minimal surgical correction (genioplasty or osteotomy when necessary). Group 3: 15 patients
(9 males; 6 females) with type 2b and type 3 mandibular hypoplasia treated with orthodontic
appliances in association with major maxillofacial surgery (osteotomy or autogenous
costochondral graft construction). The results for patients treated during childhood were
compared to a group treated during adulthood.
CONCLUSION: The success of treatment depends on the potential of midface vertical
growth which is greater during the mixed dentition stage when the primary teeth are shed
and the permanent teeth erupt. Treatment after completion of permanent tooth eruption is
less efficient and the overall results are less favourable. Diagnosis, a multidisciplinary
approach and treatment planning are important requirements for the correction of facial
deformity in this group of patients. Re-establishment of the physical appearance can greatly
increase the quality of life of HFM patients with a significant psychological and functional
impact.
OP4 EVALUATION OF TREATMENT EFFECTS AFTER BONE ANCHORED
MAXILLARY PROTRACTION IN GROWING CLASS III PATIENTS – A CONE BEAM
COMPUTED TOMOGRAPHY STUDY
Neel de Vos Riis1, Paolo Cattaneo1, Jytte Buhl2, Thomas Klit Pedersen1, 1Orthodontic
Section, Aarhus University and 2Department of Maxillofacial Surgery, Aarhus University
Hospital, Denmark
AIMS: To evaluate dental and skeletal changes in the maxilla, mandible and relating hard
tissue structures in growing Class III patients treated with bone anchored maxillary
protraction (BAMP).
SUBJECTS AND METHOD: Sixteen patients (9 males, 7 females), mean age 13.1 years
with maxillary hypoplasia treated with Class III traction to skeletally attached bone anchors in
the zygoma crest and the mandibular canine regions. The mean treatment time was 1.3
years. Pre- and post-treatment cone beam computed tomographs (CBCT) were taken for
treatment planning and assessment of treatment effect. The control group was an age- and
gender-matched group of 22 untreated Class III malocclusion patients selected from the
AAOF Craniofacial Growth Legacy Collection with lateral cephalograms taken within the
same age interval. CBCT scans were analyzed with the software Mimics®. Three reference
planes were constructed by sella, nasion, anterior nasal spine and a new landmark defined
as ‘Cribriform Plate Mid’. Thirteen linear and nine angular measurements in relation to
skeletal and dental landmarks in the maxilla, mandible and relating hard tissue structures
were carried out by one examiner and intra- and inter-group comparisons were undertaken.
Intra-observer reliability using Dahlberg’s formula, a paired t-test and a Bland-Altman plot
was conducted. The variables were normally distributed (Kolmogorov-Smirnov test) and the
parametric Student’s t-test was used to detect statistical significant differences.
RESULTS: Intra-observer reliability for the new three-dimensional cephalometric analysis
was found to be acceptable. Significant treatment effects were found at variables to point A
of the maxilla in the vertical and sagittal direction, mandibular incisor inclination, ANB, Wits
appraisal and overjet.
CONCLUSION: BAMP treatment showed a statistically significant advancement of the
maxilla, both in the sagittal and vertical direction, without dental or skeletal side-effects.
OP5 FACIAL ASYMMETRY IN UNILATERAL POSTERIOR CROSSBITE AFTER
PALATAL EXPANSION IN THE PRIMARY AND EARLY MIXED DENTITION PHASES – IS
THERE A DIFFERENCE?
Jasmina Primozic1, Vinka Rajkovic2, Stephen Richmond3, Alexei Zhurov3, Maja Ovsenik1,
1
University of Ljubljana, 2Orthos, Institute of orthodontics and maxillofacial othopaedics,
Ljubljana, Slovenia and 3University of Cardiff, U.K.
AIMS: To compare facial asymmetry in unilateral functional crossbite subjects after rapid
palatal expansion (RPE) performed either in the primary or early mixed dentition phase.
SUBJECTS AND METHOD: Twenty eight subjects (21 females, 7 males, aged 6.3 ± 1.8
years) with a unilateral functional crossbite were divided according to the dentition phase
into primary (pXB; aged 4.7 ± 1.8 years) and early mixed (emXB; aged 7.8 ± 1.3 years)
dentition groups. The subjects were treated by not more than 1 months’ RPE followed by a
retention period of up to 6 months. Three-dimensional facial images were collected with noninvasive stereophotogrametric cameras at baseline and at the 1 year follow-up. Facial
asymmetry was quantitatively assessed for the whole face and for the upper (forehead),
middle (maxillary) and lower (mandibular) parts of the face separately. Between group
comparisons were performed using the Mann-Whitney U-test.
RESULTS: At baseline, no significant differences (P > 0.05) in facial asymmetry were
observed between the groups, neither for the whole or any part of the face, although the
percentage of facial asymmetry in the lower part of the face was smaller in the pXB (39.90 ±
29.5%) as compared to the emXB (50.36 ± 24.4%) group. Furthermore, the lower part was
significantly more asymmetric (P < 0.01) in comparison to the upper and middle parts of the
face. At the 1 year follow-up, asymmetry of the lower part of the face decreased in both
groups equally and no significant differences were observed between the two groups after
treatment.
CONCLUSION: RPE in unilateral functional crossbite in either the primary or early mixed
dentition phase appears to be equally effective in terms of facial asymmetry correction,
particularly in the lower part of the face.
OP6 IS ORTHODONTICS PRIOR TO 11 YEARS OF AGE EVIDENCE-BASED? A
SYSTEMATIC REVIEW AND META-ANALYSIS
Radha Sunnak, Ama Johal, Padhraig Fleming, Department of Orthodontics, Queen Mary
University of London, U.K.
AIMS: To determine whether interceptive orthodontics prior to 11 years of age is more
effective than later treatment in the short- and long-term.
MATERIALS AND METHOD: Multiple electronic databases were searched, authors were
contacted as required and reference lists of included studies were screened. Randomised
and quasi-randomised controlled trials were included, comparing children under the age of
11 years requiring interceptive orthodontic correction for a range of occlusal problems, to an
untreated or positive control group. Data extraction and quality assessment were performed
independently and in duplicate.
RESULTS: Twenty-two studies were potentially eligible for meta-analysis, the majority
related to growth modification. Other outcomes considered included correction of unilateral
posterior crossbite, anterior open bite, extractions and ectopic maxillary canines. Metaanalysis was possible for 11 comparisons. For Class II correction in the short-term, metaanalyses demonstrated a statistically significant reduction in ANB [–1.4°, 95% confidence
interval (CI): –2.17, –0.64] and overjet (–5.80 mm, 95% CI: –6.36, –5.24) with both functional
appliances and headgear versus controls. In the long-term, however, statistical significance
was not found. Treatment duration was prolonged with both functional appliances (10.83
months, 95% CI: 7.94, 13.72) and headgear (12.47 months, 95% CI: 8.67, 16.26) compared
to adolescent treatment. Meta-analyses were not possible for comparisons of other
interceptive treatments due to heterogeneity and methodological limitations.
CONCLUSION: Evidence proving interceptive orthodontics carries additional benefit over a
single phase in adolescence is lacking.
OP7 ORTHODONTIC TOOTH MOVEMENTS AND REGENERATIVE PERIODONTAL
PROCEDURES IN THE TREATMENT OF SEVERE INTRABONY DEFECTS
Christina Tietmann1, Peter Wuellenweber2, Frank Broeseler1, Tamar Axelrad3, Soeren
Jepsen3, 1Zahnärztliche Praxis für Parodontologie, Aachen, 2Kieferorthopädische Praxis,
Aachen and 3Department of Periodontolgoy, Operative and Preventive Dentistry, University
of Bonn, Germany
AIMS: Severe periodontal destruction can lead to tooth malpositioning which often
compromises aesthetics, occlusal stability and long-term prognosis. Therefore orthodontic
tooth movement in advanced periodontal attachment loss requires an interdisciplinary
approach of regenerative periodontal and orthodontic therapy. Because there is only very
limited data, it was the aim of this retrospective clinical cohort study to evaluate the
outcomes of regenerative treatment of intrabony defects in conjunction with orthodontic tooth
movements in patients with severe periodontitis.
MATERIALS AND METHOD: A total of 526 periodontally severely compromised teeth in 48
patients (age 29-66 years) were treated using bovine derived bone mineral with/without
collagen membrane and/or enamel matrix derivative. Orthodontic tooth movements were
initiated three months after surgery. Bone levels were measured at the time of surgery.
Periodontal probing depths and digitized and calibrated periapical radiographs were
assessed at T0, at 12 months and up to 36 months. Changes in radiographic bone levels
were the primary outcome.
RESULTS: Radiographic analysis showed a mean mineralized tissue gain of 4.41 mm at 12
months (median: 4.44 mm-IQR 1.61)) with further improvements of 5.04 mm (median: 4.84IQ 1.33) up to 3 years post-operatively. No differences in treatment modalities of
regenerative therapy as well as adjunctive antibiotic therapy with regard to radiographic
bone gain were shown.
CONCLUSION: The results indicate favourable clinical and radiographic outcomes after
periodontal regenerative therapy followed by orthodontic tooth movement. Regenerative
periodontal treatment of intrabony defects in conjunction with orthodontic tooth movement
resulted in substantial radiographic bone gain up to 3 years.
OP8 AESTHETIC OUTCOME OF AUTOTRANSPLANTED PREMOLARS REPLACING
MAXILLARY INCISORS: A RETROSPECTIVE STUDY
Stephanie Tourne1, Stani Politis2, Dick Barendregt3, Guy De Pauw1, Pawel Plakwicz4,
1
Department of Orthodontics, University of Ghent, Belgium, 2Hospital ZOL, Genk, Belgium,
3
Practice ParoRotterdam, Rotterdam, Netherlands and 4University of Warsaw, Poland
AIMS: To evaluate the aesthetic outcome of autotransplanted premolars to the anterior
maxilla.
SUBJECTS AND METHOD: A cross-sectional study of 29 patients (17 males, 12
females).who had autotransplantation of a premolar to the maxillary incisor region. The
mean age of the patients was 19 years (range 11-36 years). Different restorations were
chosen for the transplanted premolar: build-up with composite or porcelain laminate veneer.
The mean observation time was 9.25 years (range: 1-34 years). The aesthetic outcome was
rated using the Pink Esthetic Score (PES) and the White Esthetic Score (WES). Patients
rated aesthetics by means of 100 mm visual analogue scales.
RESULTS: Thirty-one per cent were aesthetic failures (PES and/or WES < 6), mainly due to
a low WES. The remainder demonstrated acceptable aesthetics. Patients with a porcelain
veneer scored significantly higher for the WES (P = 0.026).
CONCLUSION: The aesthetic outcome was in some ways disappointing. This result was
mainly due to a low WES. Laminate veneers might be better to provide a more aesthetic
result. On the other hand, patients responded very favourably regarding the treatment
outcome.
OP9 INTEGRATED ORTHODONTIC TREATMENT OF ONCOLOGICAL PATIENTS – A
CASE CONTROL STUDY WITH A TWO-YEAR FOLLOW-UP
Maria Mitus-Kenig1, Elzbieta Pawlowska2, Magdalena Durka-Zajac3, 1Department of
Stomatological Prevention and Hygiene, Jagiellonian University Medical College, Krakow,
2
Department of Orthodontics, Medical University, Lodz and 3The Specialist Orthodontic
Practice, Szczecin, Poland
AIMS: It is estimated that 1/900 young adults successfully completed cancer treatment in
their childhood. The result is an increasingly common contact of orthodontists with this group
of patients. The aim of this study was to compare the results of integrated treatment of
cancer survivors with a control group of healthy subjects.
SUBJECTS AND METHOD: Forty eight patients treated orthodontically between 2008 and
2013 (28 males, 20 females; median age 19.4 years). Thirty patients were cancer survivors
and 18 subjects were in maintenance therapy. Moreover, 48 healthy control subjects
matched for age, gender, and malocclusion served the as control group. Thirty one patients
were skeletal Class II, five skeletal Class III and 12 skeletal Class I.
RESULTS: The mean follow-up time was 24.3 months. The average time of treatment in the
study group was statistically significantly shorter (10.2, versus 17.6 months; P < 0.01). In
three and 11 patients in the oncological group root resorption and oral mucositis,
respectively were observed. In the control group, four patients had mucositis and two
allergies to nickel. There was no statistically significant difference in the outcomes achieved
in either the study or control group assessed on cephalometric images. In 10 cases,
orthodontic appliances were removed temporarily to perform imaging studies. In nine
patients, it was necessary to discontinue treatment earlier. Both short- and long-term results
of orthodontic treatment were comparable in the study and control group.
CONCLUSION: Properly conducted orthodontic treatment of cancer survivors does not
differ significantly from the results of treatment of healthy subjects both in the short- and
long-term. Close interdisciplinary cooperation with the physicians leading the cancer
treatment and follow-up allows for appropriate treatment planning.
OP10 THREE-DIMENSIONAL ANALYSIS OF SOFT TISSUE CHANGES FOLLOWING
ORTHOGNATHIC SURGERY IN SKELETAL CLASS III PATIENTS
Natasa Ihan Hren, Miha Verdenik Clinical Department of Maxillofacial and Oral Surgery,
Medical Faculty, Ljubljana, Slovenia
AIMS: The decision as to which orthognathic procedure is the best solution for a good
aesthetic result of skeletal Class III deformity is not always straightforward. Threedimensional (3D) imaging brings clear benefits in accurate measurement of facial
morphology and changes associated with treatment. The purpose of this research was to
objectively verify on 3D images if post-operative changes occur in regions not directly
affected by surgical movement of underlying bones.
SUBJECTS AND METHOD: Eighty three young adults (45 females, on average 25 ± 9
years of age and 38 males, on average 23 ± 6 years of age) with a skeletal Class III
deformity. According to the type of surgery, mandible [bilateral sagittal split osteotomy
(BSSO)] only, maxilla (Le Fort I) only. or a combination of both (bimaxillary), were classified
into three groups. The pre- and post-operative scans of the facial surface were compared by
regional iterative closest point algorithm on the area of the forehead and both orbits. Shell to
shell difference analysis was performed and changes of distance between the observed
regions were calculated.
RESULTS: According to expectations, changes were greatest in the regions where
underlying bones were moved, but also no matter which surgery was performed, changes
occurred over the whole face. Significant changes were found for the nose, cheek and upper
lip region in the BSSO group and for the lower lip and chin region in the Le Fort I group
confirming the concept of the facial soft tissue mask acting as one unit.
CONCLUSION: Facial soft tissues changes after surgery are more complex than bone
movements.
OP11 THE IMPACT OF HYPODONTIA ON ORAL HEALTH-RELATED QUALITY OF LIFE
IN CHILDREN
Azza Al-Ani, Joseph Antoun, Cindy Mullens, Mauro Farella, University of Otago, Dunedin,
New Zealand
AIMS: Hypodontia is one of the most common dental anomalies, which may have
substantial functional and psychosocial impairments. Children with severe hypodontia
appear to have poorer oral health-related quality of life (OHRQoL) than those with dental
decay and malocclusion. However, the impact of mild/moderate hypodontia (1-4 missing
teeth) on OHRQoL is still not well documented. The aims of thiss study were to investigate
the association between the Child Perception Questionnaire (CPQ-16) and mild/moderate
hypodontia.
SUBJECTS AND METHOD: The convenience sample consisted of 25 case-control pairs,
individually matched for age (±1 year), gender and treatment stage. Cases included at least
one missing lateral incisor or lower second premolar, while controls showed no evidence of
tooth agenesis (excluding third molars). Patients were administered the CPQ-16 and a
global question.
RESULTS: The study sample had an average age of 15.7 ± 4.1 years, with a nearly equal
distribution of males (n = 26, 52%) and females (n = 24, 48%). Over half the study
participants were receiving orthodontic treatment (n = 28, 56%), with the remaining patients
either untreated (n = 16, 32%) or in the retention phase (n = 6, 12%). There was a distinct
gradient in mean CPQ-16 scores (overall and most domains) across the categories of selfrated oral health, with those describing their oral health as ‘poor’ reporting the highest CPQ
scores. The mean overall CPQ-16 score was slightly lower in cases (13.6 ± 8.6) than in
controls (15.0 ± 11.4; P = 0.632). There were also no significant differences between cases
and controls for the oral symptoms, functional limitations, emotional well-being and social
well-being domains (P > 0.05).
CONCLUSION: The CPQ-16 was found to be valid in this preliminary sample of
adolescents with mild/moderate hypodontia. However, there were very little differences in
OHRQoL between patients with mild/moderate hypodontia and controls. Larger samples and
more uniform types of hypodontia need to be explored in future studies.
OP12 PURE BONE BORNE MAXILLARY EXPANSION WITH FOUR MINI-IMPLANTS IN
ADULTS WITH AND WITHOUT SURGICAL ASSISTED RAPID PALATAL EXPANSION: A
CONSECUTIVE STUDY OF 35 PATIENTS***
Heinz Winsauer1, Alfred Peter Muchitsch2, Clemens Winsauer3, Doreen Jaeschke4, Andre
Walter5, Dental University of Graz, 1Bregenz and 2Graz, Austria, 3Orthodontic center
Bregenz, Austria, 4Dental University Marburg, Germany and 5Universidad International de
Catalunya, Barcelona, Spain
AIMS: To determine the possibility of palatal expansion in mature maxillae without and with
surgically assisted rapid palatal expansion (SARPE), and to quantify the amount of
expansion without SARPE in relation to age.
SUBJECTS AND METHOD: Thirty five consecutive patients (24 females, 11 males) ranging
in age from 20 years 2 months to 53 years 8 months (mean age 28 years 5 months), were
assessed concerning the need for SARPE (1) the overall opening of the expander (2), and
the intercanine and intermolar expansion values on study models (3,4). Expansion was
performed with a pure bone borne maxillary expander on four mini-implants (Micro4) initially
using a force limiting gauge and a multicycle protocol. If the diastema did not open or the
necessary width was not achieved the patient was referred for SARPE. Intercanine and
intermolar distances were measured at expander insertion and 2 months after the end of
expansion without brackets.
RESULTS: Overall without SARPE n = 29, with SARPE n = 6. The mean expander opening:
7.4 mm (SD 0.8 mm; no SARPE), 8.3 mm (SD 1.2 mm; SARPE). The mean gain in
intercanine distance: 5.1 mm (SD 0.7 mm; no SARPE), 5.8 mm (SD 0.7 mm; SARPE). Mean
gain in intermolar distance (fossa-fossa): 4.8 mm (SD 0.5 mm; no SARPE), 5.5 mm (SD 0.7
mm; SARPE).
CONCLUSION: The method of mini-implant borne palatal expansion in adults is a promising
and effective way of widening the maxilla. Only one out of four patients needed surgical
assistance for maxillary expansion. This treatment concept is minimally invasive without
major complications.
OP13 PERCEIVED ATTRACTIVENESS ON FRONTAL AND LATERAL PHOTOGRAPHS
Cristina De la Cruz Martínez, Juan Sánchez Holgado, Joaquín Sanz Coarasa, Jorge Longar
González, Javier De la Cruz Pérez, Department of Dentistry, University Alfonso X El Sabio,
Villanueva de la Cañada (Madrid), Spain
AIMS: To evaluate the differences in perceived attractiveness between frontal and lateral
photographs of the same patients, and to study the association of these differences and
characteristics of the patient (skeletal Class, gender) and the evaluator (gender, dental
background, previous orthodontic treatment).
SUBJECTS AND METHOD: Thirty (15 males, 15 females; 10 Class I, 10 Class II and 10
Class III) profile photographs of patients were shown to 109 university students (76 dental,
33 other degrees: law, engineering, etc.). One month later the same participants were shown
the frontal photographs of the same patients. The participants were instructed to score the
attractiveness of the patients on a form (0 = most ugly to 10 = most attractive) for both sets
of photographs. The participants were unaware they were scoring the same patients. For
every evaluator the scoring difference between frontal and profile photograph (P-F) was
found. The Kolmogorov-Smirnov test showed a non-normal distribution. The Mann-Whitney
U test was used to compare the differences for the gender of the patient and participant and
university studies (dental versus non-dental). The Kruskal Wallis test was performed to
compare the differences between profile and frontal photographs according to the skeletal
Class of the patient and previous or present orthodontic treatment of the participant. Later,
pairwise comparison was performed with a Mann-Whitney test.
RESULTS: Perceived attractiveness was 0.07 ± 2.7 higher for frontal than for profile
photographs. Female participants scored the profile photographs higher (0.19 ± 2.7)
whereas males scored the frontal photographs higher (0.47 ± 2.6; P < 0.001). No statistically
significant differences were found between the difference of proportion (P-F) and patient
gender (P = 0.062). Dental students preferred frontal photographs (–0.23 ± 2.6) and the
remainder of the students the profile photographs (0.31 ± 2.8; P < 0.001). Regarding skeletal
Class, Class II scored less on profile photographs than Class I and III (–0.51 ± 2.7; P <
0.001). No differences in scoring between Class I and III were found (P = 0.559). Present or
past orthodontic treatment of the evaluator did not yield significant differences in scoring (P =
0.950)
CONCLUSION: In this sample of university students, profile and frontal photographs of
patients were scored differently for perceived attractiveness. Males and dental students
preferred frontal, and female and non-dental students preferred profile photographs. Class II
subjects were perceived less attractive from a lateral view.
OP14 IMPACT OF SELF-ESTEEM AND PERSONALITY TRAITS ON THE ASSOCIATION
BETWEEN ORTHODONTIC TREATMENT NEED AND ORAL HEALTH-RELATED
QUALITY OF LIFE IN ADULTS SEEKING ORTHODONTIC TREATMENT
Maïté Clijmans1, Jurgen Lemiere2, Steffen Fieuws3, Guy Willems1, Department of Oral
Health Sciences - Orthodontics, KULeuven, 2Child and Adolescent Psychiatry/Pediatric
Haemato-Oncology, KULeuven, UZ Gasthuisberg, 3Interuniversity Institute for Biostatistics
and Statistical Bioinformatics, KULeuven and Universiteit Hasselt, Leuven, Belgium
AIM: To investigate whether an association exists between orthodontic treatment need and
oral health-related quality of life (OHRQoL) and whether this association is moderated by
self-esteem (SE) and/or personality traits.
SUBJECTS AND METHOD: In this cross-sectional study comprising 189 adults (55 males,
134 females) aged 17 years or older (mean age 31.3 years), the OHRQoL was scored with
the use of the shortened version of the Oral Health Impact Profile (OHIP-14). The
Rosenberg Self-Esteem (SE) scale was used to evaluate SE, and the Dutch adaptation of
the Neuroticism-Extraversion-Openness Five Factor Inventory (NEO-FFI) to assess
personality profiles. Need for treatment was defined by the Index of Orthodontic Treatment
Need. Spearman correlations, Mann-Whitney U tests, and regression models were used to
analyze the data.
RESULTS: There was a modest to weak association between treatment need (Dental Health
Component and Aesthetic Component) and OHRQoL as measured by the total OHIP-14
score (rho = 0.21, P = 0.01216; rho = 0.18, P = 0.02960, respectively). A significant, yet
modest to weak association between SE and the total OHIP-14 score was found (rho = –
0.34, P = 0.00057). Moreover, significant associations were found for the total OHIP-14
score and neuroticism and extraversion. Significant associations were observed between SE
and all personality traits.
CONCLUSIONS: There was a significant association between orthodontic treatment need
and OHRQoL. Moreover, a significant association could be found between SE and
OHRQoL, as well as certain personality traits and OHRQoL. No evidence was found that SE
or personality traits moderate the association between OHRQoL and treatment need.
OP15 CHANGES OF ORAL HEALTH RELATED QUALITY OF LIFE DURING AND AFTER
ORTHODONTIC TREATMENT
Fahimeh Farzanegan1, Farzin Heravi1, Elham Noori2, 1Department of Orthodontics, Mashhad
University of Medical Sciences and 2Private practice, Mashhad, Iran
AIMS: To investigate the changes in oral health related quality of life (OHRQoL) among
adolescents during and after fixed orthodontic appliance therapy.
SUBJECTS AND METHOD: In this prospective study, 71 patients (19 males, 52 females)
aged 14-17 years who had sought fixed orthodontic treatment were included. In order to
assess OHRQoL, each subject was asked to complete a reliable and valid Iranian form of
the OHRQoL questionnaire which evaluated four domains consisting of oral symptoms,
functional limitations, emotional wellbeing and social wellbeing at four time points: before
treatment (T0) at 2 (T1) and 6 (T2) months after placement of the fixed appliance, and 3
months after the removal of the fixed appliance (T3). In addition, to evaluate their
expectations at T0, they were given a similar questionnaire to complete that asked them to
imagine their life after treatment. A repeated measurement test was used to compare the
relative changes of OHRQoL and its domains at the different time points. In order to evaluate
the differences between the results of treatment and their expectations¸ a t-test was used.
RESULTS: OHRQoL and its domains showed no significant differences between boys and
girls at any time point. OHRQoL and all domains, except emotional wellbeing, were
decreased at T1 compared with T0, but at T2 and T3 improvement in OHRQoL and all of its
domains were observed relative to T0. There were significant differences between OHRQoL
emotional and social wellbeing of patients after treatment and their expectations.
CONCLUSION: Orthodontic treatment can have a positive influence on the quality of life.
Although orthodontic treatment might be associated with some problems and discomfort at
the beginning of the procedure, with progression of treatment all of the quality of life domains
increased. At the end of treatment, OHRQoL never reached the level of patients'
expectations.
OP16 IMPACT OF SOCIOECONOMIC FACTORS ON ORAL HEALTH-RELATED
QUALITY OF LIFE IN A COHORT OF ORTHODONTIC PATIENTS
Grace Nichols1, Joseph Antoun1, Peter Fowler2, Azza Al-Ani1, Mauro Farella1, 1Department
of Oral Sciences, University of Otago, Dunedin and 2Christchurch Hospital, New Zealand
AIMS: Recent data suggests that socioeconomic factors (SES) may have a strong influence
on the perceived benefits of orthodontic treatment, including self-reported oral hHealthrelated quality of life (OHRQoL). The objective of this study was to investigate the
relationship between area-based SES and OHRQoL in a cohort of orthodontically treated
patients.
SUBJECTS AND METHOD: The study sample was based on a previous cohort of
orthodontic patients (n = 75), who were administered the Oral Health Impact Profile (OHIP14) at baseline and after orthodontic treatment. The sample included patients with severe
malocclusions, cleft lip and/or palate, and dentofacial deformities. All patients were
orthodontically treated by one author. Area-based measures of SES were determined using
the NZDep2013 index, which calculates deprivation scores for small sectors of the
population based on several variables, including household income and education level.
Malocclusion severity was evaluated using the Dental Aesthetic Index (DAI).
RESULTS: The study sample had a mean baseline age of 15.6 years (±4.3), and a slightly
higher proportion of males than females (M = 54.7%). The mean DAI score was (49.3 ±
12.9), with over 90 per cent of the patients being classified as having a severe malocclusion
(DAI >32). There were no significant differences in the mean pre-treatment OHIP-14 scores
for patients living in low (n = 25; 13.6 ± 11.7), medium (n = 26; 17.5 ± 12.3) or high (n = 24;
11.5 ± 8.2) deprivation areas (P > 0.05). Non-parametric correlations between NZDep2013
scores and several OHIP-14 variables (pre-treatment, post-treatment, change in OHIP-14)
were weak and non-significant. Moreover, the severity of a malocclusion (i.e. DAI score, P <
0.01) was the only significant variable associated with treatment-related changes in the
OHIP-14 after adjusting for age, gender and SES.
CONCLUSION: In contrast to clinical variables, socioeconomic factors do not seem to play
a major role in the OHRQoL of orthodontic patients with severe malocclusions and/or
dentofacial deformities. Future research into the effect of individual-based measures of SES
is needed to complement the findings of this study.
OP17 COMPARISON OF IBUPROFEN WITH CHEWING GUM ON PAIN REDUCTION
AFTER INITIAL ARCHWIRE PLACEMENT IN ORTHODONTIC PATIENTS
Faizan Ali, Javeria Asif Cheema, Rabia Aziz, Department of Orthodontics, Children Hospital
& Institute of Child Health, Lahore, Pakistan
AIMS: To ascertain whether chewing gum provides pain relief of an equivalent or greater
magnitude to ibuprofen after initial archwire placement in orthodontic patients.
SUBJECTS AND METHOD: This randomized clinical trial study included 42 patients, 21
girls and 21 boys, between the ages of 12 and 17 years classified into three groups of 14
each: group A (placebo treated), group B (ibuprofen treated) and group C (given chewing
gum). The patients in each group were treated after placement of the initial archwire and
every 8 hours if they experienced pain. A visual analogue scale was used to record pain
perception at 2 hours, 6 hours, bedtime, 24 hours, 2 days, 3 days, and 7 days after archwire
placement during chewing, biting, clenching anterior and posterior teeth. Analysis of
variance and Tukey’s tests were used for data analysis.
RESULTS: There was a significant decrease in pain perception of chewing function
between group A and group C at 6 hours and 3 days (P < 0.05), between group A and group
C in pain severity when clenching posterior teeth at 24 hours (P < 0.05) and between group
C and group B during biting and clenching anterior teeth at 24 hours and 7 days. No
significant differences were recorded at other times or for other functions.
CONCLUSION: Chewing gum is effective for pain reduction in orthodontic patients and can
be recommended as a suitable substitute for ibuprofen.
OP18 HERBST APPLIANCE TREATMENT – LINGUAL VERSUS LABIAL: DOES IT MAKE
A DIFFERENCE?
Niko Bock1, Sabine Ruf 1, Theresa Jilek2, 1Department of Orthodontics, University of Giessen
and 2Private Practice, Bad Essen, Germany
AIMS: To analyse and compare treatment (tx) effects during Herbst multibracket appliance
(MBA) tx when combined with a fully customized lingual or a standard labial MBA.
SUBJECTS AND METHOD: Eighteen Class II division 1 patients (overjet ≥5 mm, Class II
molar relationship ≥0.5 cusp width bilaterally or 1 cusp width unilaterally, 11 females and
seven males, median age 16.0 years) treated with a fully customized lingual MBA (Incognito,
3M; = group LING) in combination with a Herbst appliance were retrospectively matched
(molar relationship and skeletal maturity) to 18 Class II division 1 patients (13 females, 5
males, median age 15.7 years) treated with a standard labial MBA (Tip-Edge, TP
Orthodontics; = group LAB). Lateral cephalograms from before, during and after tx were
analysed using the SO-analysis by Pancherz and additional parameters for lower incisor
position/inclination.
RESULTS: During the Herbst phase larger average amounts of overjet and molar
relationship changes were seen in the LAB (7.7/5.7 mm) than in the LING (5.3/4.4 mm)
group. These group differences were due to the fact that in the LAB group the patients were
treated to overcorrected sagittal occlusal relationships. During the total tx period (Herbst plus
MBA) the average amounts of overjet and molar relationship changes were similar in both
groups: LAB (4.9/3.7 mm) and LING (4.2/3.5 mm). Overjet correction was achieved by 38
per cent skeletal and 62 per cent dental changes in the LAB group and 45 per cent skeletal
and 55 per cent dental changes in the LING group. The sagittal molar relationship correction
resulted from 53 per cent skeletal and 47 per cent dental effects in the LAB group and 56 per
cent skeletal and 44 per cent dental changes in the LING group. The changes in lower
incisor inclination and lower incisor edge position were significantly larger in the LAB than in
the LING group during the Herbst phase (iiL/ML: +5.8°/+13.6°, P = 0.002; ii-MLp: +2.5/+4.0
mm, P = 0.004). For the Herbst plus MBA phase, no significant differences were found
(iiL/ML: +4.5°/+7.5°; ii-MLp: +2.3°/+2.3°).
CONCLUSION: The fully customized lingual MBA was able to reduce the amount of lower
incisor proclination during Herbst multibracket treatment compared to a standard labial MBA.
Statistically significant differences, however, were not seen for the total tx period (Herbst
plus MBA) but only for the Herbst phase.
OP19 COMPARISON OF ORTHODONTIC TREATMENT DURATION AND PEER
ASSESSMENT INDEX SCORES OF CLASS II PATIENTS
Eleni Malamou, Derya Cakan-Germec, Feyza Ulkur, Department of Orthodontics, Yeditepe
University, Dental Faculty, Istanbul, Turkey
AIMS: To compare the duration and quality of treatment outcome using the Peer
Assessment Rating (PAR) Index for evaluation of occlusal outcome of Class II patients
treated with non-extraction and extraction treatment protocols.
MATERIALS AND METHOD: The archived records of 157 subjects with a complete Class II
malocclusion treated by premolar extraction or non-extraction treatment. For every patient,
the pre- and post-treatment casts, the initial and final cephalograms and the initial and final
records were collected. Before data collection the names on the records were covered in
order for the sample to be blindly investigated. The subjects were divided into two groups.
Group 1 included 81 patients (42 females, 39 males, mean age: 12.52 years) treated nonextraction and group 2, 76 patients (25 males, 51 females, mean age: 14.49 years) treated
with extractions. One researcher evaluated all subjects. Pre- and post-treatment dental casts
were measured and scored with the PAR Index. The duration of each treatment was
evaluated by recording the beginning and finishing treatment dates.
RESULTS: There was no significant difference between the groups in terms of treatment
duration, percentage of PAR reduction and treatment efficiency index (P > 0.05). Treatment
efficiency was the same in both groups.
CONCLUSION: Premolar extraction and non-extraction treatment protocols have the same
treatment efficiency. There was no significant difference in the duration of treatment between
the two groups.
OP20 CLINICAL OUTCOMES OF DIFFERENT CLASS II TREATMENT MODALITIES
USING THE AMERICAN BOARD OF ORTHODONTICS OBJECTIVE GRADING SYSTEM
Hatice Akinci Cansunar1, Tancan Uysal2, 1Inonu University, Malatya and 2Izmir Katip Celebi
University, Izmir, Turkey
AIMS: To evaluate the clinical outcomes of three different Class II treatment modalities (two
upper premolar extractions, headgear. and functional orthopaedic treatment) followed by
fixed orthodontic therapy, using the American Board of Orthodontics Objective-GradingSystem (ABO-OGS).
MATERIALS AND METHOD: A retrospective sample of treated patients was randomly
selected from the archives of postgraduate orthodontic clinics in different cities in Turkey.
From 1684 sets of post-treatment records, the selected 669 patients’ were divided into three
groups: group 1 comprised 269 patients (124 females, 145 males) treated with two upperpremolar extractions, group 2, 198 patients (103 females, 95 males) treated with cervical
headgear and group 3, 202 patients (120 females, 82 males) treated with functional
appliances (Twin Block or fixed-functional appliances, Forsus and Herbst). The total sample
contained 347 females and 322 males with an average age of 14.3 years at the start of
treatment. Only one researcher evaluated all cases using the ABO-OGS. Chi-square, Z-test
and multivariate analysis of variance were used for statistical evaluation at the P < 0.05
level.
RESULTS: No statistically significant differences were found among the three groups in
buccolingual inclination, overjet, occlusal relationship, and root angulation. Among the three
groups, significant differences were determined in alignment, marginal ridge height, occlusal
contact and interproximal contact measurements and overall OGS average scores. A
statistically significant difference was found in the mean treatment time between the
extraction and functional appliance groups (P = 0.017).
CONCLUSION: Headgear treatment finished better than functional appliances according to
total ABO-OGS scores. The headgear group had better tooth alignments than the extraction
group. The headgear group had better occlusal contacts than the functional appliance group,
and lower average scores for interproximal contact measurements. Functional appliances
had the poorest average scores for marginal ridge height.. Additionally, the longest treatment
time was found in the functional appliance group.
OP21 THE QUALITY OF THE EVIDENCE ACCORDING TO GRADE IS
PREDOMINANTLY LOW OR VERY LOW IN ORAL HEALTH SYSTEMATIC REVIEWS
Nikolaos Pandis1, Padhraig Fleming2, Helen Worthington3, Georgia Salanti4, 1University of
Bern, Switzerland, 2Queen Mary University of London, U.K., 3University of Manchester, U.K.
and 4Univeristy of Ioannina, Greece
AIMS: Limited information exists on the overall quality of the evidence in oral health. There
is increasing concern of a gulf between research evidence and its clinical applicability. A
system capable of simultaneously assessing the quality of the evidence, balancing benefit
and harm, while accounting for patient preferences and aiding clear treatment
recommendations is imperative. The Grades of Recommendation, Assessment,
Development, and Evaluation (GRADE) initiative has become an accepted approach for
assessing the evidence and for making recommendations. The main objective of this study
was to assess the quality of the evidence using GRADE in oral health systematic reviews on
the Cochrane Database of Systematic Reviews (CDSR) and high impact general and dental
specialty journals.
MATERIALS AND METHOD: Systematic Reviews (2008-2013) from 14 high impact general
dental and specialty dental journals and the CDSR were screened for meta-analyses.
Eligible SRs included at least one meta-analysis of at least two studies. The selected metaanalysis was that reporting on the primary outcome or the first or most important reported
outcome. Meta-analyses were assessed in relation to the quality of the evidence in the five
domains specified within GRADE: limitations in study design and/or execution (risk of bias),
inconsistency of results, indirectness of evidence, imprecision of results, and publication
bias. Data was collected at the SR, meta-analysis and trial level. Two reviewers applied and
agreed on the GRADE rating for the selected meta-analyses.
RESULTS: From the 510 systematic reviews initially identified, 91 reviews (41 Cochrane
and 50 non-Cochrane) were eligible for inclusion. The GRADE assessment indicated that
the quality of evidence was high/moderate in only 20 per cent of meta-analyses with no
difference between Cochrane and non-Cochrane reviews. The most common domains
prompting downgrading of the evidence were study limitations and imprecision. No
association was observed between evidence quality and journal impact factor or year of
publication.
CONCLUSION: The quality of the evidence in oral health, assessed using GRADE, is
predominantly low or very low suggesting an urgent need for more studies of higher quality
in order to inform clinical decisions thereby reducing the risk of instituting potentially
ineffective and/or harmful therapies.
OP22 WHICH WHITE WIRE? A MULTI-CENTRE RANDOMISED CONTROLLED TRIAL
ON ALIGNMENT EFFICIENCY AND COLOUR PERFORMANCE
Zaid Esmail, Aman Ulhaq, Anis Kamaruddin, Dirk Bister, Martyn Sherriff, Department of
Orthodontics, King's College London, U.K.
AIMS: To evaluate the alignment efficiency and colour performance of four coated nickeltitanium aligning archwires over an eight-week period. The aim was to establish whether the
latest aesthetic archwires have dispelled their reputation.
SUBJECTS AND METHOD: One hundred and twenty participants requiring fixed appliance
orthodontic treatment had each dental arch randomly allocated to one of four interventions:
(1) Forestadent® BioCosmetic® 0.017 inch (2) Forestadent® Titanol® Cosmetic 0.016 inch
(3) TP Orthodontics Aesthetic 0.014 inch (4) Ortho Organizers® Tooth Tone® 0.016 inch.
The archwires were ligated and remained in situ for an eight week period. Changes in Little's
Irregularity Index were measured on dental casts using digital callipers and retrieved
archwires were measured for colour change (ΔE) and coating loss. Colour assessments
were made using digital photography and Adobe® Photoshop®, with ΔE values computed
using the CIE L*a*b* system. Coating loss was measured by analysing digitally scanned
images and using Autodesk® AutoCAD®.
RESULTS: One hundred and nineteen patients (74 females, 45 males) completed the trial.
Significant alignment was achieved in all groups, however, one-way ANOVA showed no
difference in alignment efficiency among the four groups. All four archwires showed
significant mean colour change and coating loss after clinical use. One-way ANOVA showed
a statistically significant difference between the archwires for ΔE (P = 0.001), with Titanol
Cosmetic showing the greatest statistically significant colour change. There was no
statistically significant difference between the archwires for coating loss.
CONCLUSION: There was no difference in alignment efficiency amongst the coated
archwires used, however there was appreciable colour change and coating loss after clinical
use of coated aligning archwires. The aesthetic properties of these coated archwires are not
ideal.
OP23 A NOVEL PANEL OF SPECIFIC PROTEIN BIOMARKERS FOR ROOT
RESORPTION ASSOCIATED WITH ORTHODONTIC TOOTH MOVEMENT FOR USE IN
EVERYDAY CLINICAL PRACTICE
Karolina Kaczor-Urbanowicz, Omer Deutsch Aaron Palmon, Stella Chaushu, Institute of
Dental Sciences, The Hebrew University- Hadassah Dental School of Medicine, Jerusalem,
Israel
AIMS: The discovery of specific salivary biomarkers for root resorption (RR) induced by
orthodontic treatment is one of the critical challenges in orthodontics. RR is the most
prevalent and unavoidable consequence of orthodontic tooth movement, detected only on
radiographs, which have many disadvantages, such as: delayed diagnosis or radiation
exposure. The role of potential biomarkers for RR in saliva has been scarcely studied.
Therefore, there is still no known panel of diagnostic biomarkers that can be used in
everyday clinical practice, in order to identify patients at risk of developing RR. The aim of
this study was to investigate and to establish a panel of specific protein biomarkers for RR
associated with orthodontic tooth movement.
SUBJECTS AND METHOD: Unstimulated saliva was collected from 48 RR patients (31
females, 17 males) and 24 healthy age and gender matched controls (13 females, 11
males). Periapical radiographs of the four upper incisors were taken before and 9 months
after upper bonding. Afterwards, the patients were divided according to age and severity of
RR. High-abundance proteins were depleted using triple depletion methodologies followed
by two-dimensional-gel-electrophoresis, quantitative mass spectrometry and biofunctional
analysis. Individual validation of proteins was performed by Western blotting.
RESULTS: Mass spectrometry revealed 267 new potential protein biomarkers in young (1020 years of age), and 78 in adult (21-30 years of age) patients with severe RR associated
with orthodontic tooth movement. Furthermore, the bioinformatic analysis of proteins in
young patients with severe RR revealed pathogenesis mechanisms related to actin
cytoskeleton regulation complex and Fc gamma R-mediated phagocytosis, while in adult
patients with severe RR a disclosed pathway was associated with focal adhesion. However,
most importantly, a panel of specific protein biomarkers involved in those pathways, such as
alpha-2-HS-glycoprotein or actin-related protein 2/3 complex, was individually validated.
CONCLUSION: Patients suffering from RR associated with orthodontic treatment exhibited
a unique panel of specific protein biomarkers, showing an increase of protein expression
profiles with the greater degrees of RR. As new evidence emerges, it may be possible to
develop a cost effective and easy to use diagnostic tool, such as a salivary test strip, in order
to identify orthodontic patients at risk of developing RR in everyday clinical practice.
OP24 COMBINED ORTHODONTIC AND ORTHOGNATHIC SURGICAL TREATMENT IN
PATIENTS OVER 40 YEARS OF AGE
Thomas Präger1, Max Zinser2, Joachim Zöller2, Robert Mischkowski2, 1Department of
Orthodontics, Dentofacial Orthopedics and Pedodontics, Charité - Universitätsmedizin Berlin
and 2Department of Oral and Maxillofacial Surgery, University Hospital Cologne, Germany
AIMS: In recent years, there has been substantial growth in the number of adults seeking
orthodontic treatment. Subsequently, more elderly patients are now undergoing orthognathic
surgery. The aim of this study was to investigate the characteristics and the outcomes of the
treatment of patients over the age of 40 years who received orthognathic surgery.
SUBJECTS AND METHOD: In this retrospective cohort study all patients receiving
orthognathic surgery during the period from 1998 to 2008 were assessed. Those older than
40 years with complete documentation (records, dental casts and radiographs) were
assigned to the group of elderly patients. Demographic data including the patient’s age and
gender, as well as the indication and the characteristics of the orthodontic and surgical
treatment were collected.
RESULTS: Thirty one (10 males, 21 females) out of 637 patients were older than 40 years
and completely documented. In 71 per cent of these patients, the main motivation for
treatment was an improvement of the occlusion; in every second due to prosthodontic
reasons. Aesthetics was most important for 23 per cent, and only 6 per cent underwent
surgery because of sleep apnoea. The majority of surgical procedures was mono-maxillary
(68%), and most frequently in the upper jaw (mainly Le Fort I osteotomy), followed by
segmental osteotomy. Two patients underwent a Le-Fort-III distraction for hypoplasia of the
midface associated with Crouzon syndrome. The majority of patients received pre-operative
orthodontics by means of fixed appliances, but only one patient had lingual orthodontics.
About 10 per cent were treated by means of removable appliances.
CONCLUSION: In spite of generally higher aesthetic demands, the improvement of
functional disturbances is the main reason for older patients to undergo orthognathic
surgery. Aesthetics and sleep apnoea play only a secondary role. The general principles of
the procedures vary only marginally from those in younger patients.
OP25 DENTAL CALCIFICATION STAGES AS DETERMINANTS OF THE PEAK GROWTH
PERIOD
George Litsas1, Athanasios Athanasiou2, Ioulia Ioannidou-Marathiotou3, 1Practice, Kozani,
Greece, 2Dubai College of Dental Medicine, Dubai, United Arab Emirates and 3Department
of Orthodontics, Aristotle University of Thessaloniki, Greece
AIMS: To investigate the diagnostic accuracy of dental maturation stages for the
identification of individual-specific skeletal maturation phases.
MATERIALS AND METHOD: From a pre-treatment cohort of 420 consecutive patients, 255
were identified, comprising 145 girls (mean age: 12.12 years) and 110 boys (mean age:
12.18 years). In total, 510 radiographs (255 lateral cephalometric and 255 panoramic
radiographs) were evaluated. Dental maturity was assessed through the calcification stages
of the mandibular canine, premolars and second molar. Determination of the growth phase
was assessed according to the cervical vertebral maturation (CVM) method. Statistical
elaboration included Spearman Brown formula, Spearman’s rho correlation coefficient and
positive likelihood ratios (LHRs). A positive LHR threshold of 10 or more was considered for
satisfactory reliability of any dental maturation stage for the identification of any of the CVM
growth phases.
RESULTS: The second molars showed the highest (r = 0.725) and canines (r = 0.463) the
lowest correlation (P < 0.001). Positive LHR values greater than 10 seen for the identification
of pre-peak growth phase were observed for the second molar (stage D, 14.4), second
premolar (stage E, 11.1) and first premolar (stage D, 16 and stage E, 20). Positive LHR
values for the identification of peak growth phase were seen only for the second molar
(stage F, 13.6). For the identification of the post-peak growth phase positive LHR values
were seen again for the second molar (stage H, 18.9). Taking into account the clinical
diagnostic performance of the second molar to identify growth phases, the positive LHRs for
dental maturation stages of the second molar for the diagnosis of CVMS II was calculated.
Positive LHR values greater than 10 were seen for the identification of CVMS II (stage D,
10.2).
CONCLUSION: Dental maturation evaluation is useful as a preliminary diagnostic tool for
skeletal growth assessment. Second molar calcification stages have reliable diagnostic
performance for the identification of the pubertal growth spurt.
OP26 ORTHODONTICALLY INDUCED EXTRACTION IN GERMANY – A SURVEY ON
PREVALENCE, LOCALISATION AND INDICATION
Susanne Wriedt, Alessja Indin-Wolf, Heinrich Wehrbein, Department of Orthodontics, J.Gutenberg University Medical Center, Mainz, Germany
AIMS: To update the rate and indication for orthodontically induced extractions in Germany.
MATERIALS AND METHOD: The addresses of 690 orthodontists were randomised and
extracted from the register of the DGKFO. Colleagues were asked to complete a
questionnaire on the rate, reasons, and localisation of prescribed extractions. Two hundred
and fifteen questionnaires were assessed (response rate 31.2%). Descriptive analysis,
Spearman correlation, and Wilcoxon test were performed using SPSS20.
RESULTS: Three colleagues did not specify the rate of extraction. Seven colleagues (3.3%)
never prescribed extraction. Extractions averaged 13.6 per cent of all patients. Prescription
of extraction was ‘rare’ (<6%) in 63 (29%), ‘few’ (6-10%) in 58 (27%), ‘average (11-20%) in
51 (24%), and ‘often’ (>20%) in 33 (15%) offices. The reasons for extractions were anterior
length discrepancy (ALD) (45%), compensation of aplasia or hypoplasia (19%), caries (9%)
or Class II relationship (9%). The more extractions were prescribed, the more total space
discrepancy, anterior crowding and Class II relationship were named as reasons for
extraction (P < 0.01). Most extractions concerned teeth 14/24 (33%), 34/44 (26%), 35/45
(13%), 15/25 (10%), and first molars (5%). Eighty three per cent of extractions were done
symmetrically, 40 per cent were maxillary only and 44 per cent bimaxillary. Depending on
the device, 67-74 per cent of colleagues stated that the rate of extractions were lower since
the use of interproximal enamel reduction (IER) temporary anchorage devices (TADs),
and/or fixed distalisation devices. Those using bonded retainers and/or superelastic wires
prescribed fewer extractions (P < 0.05).
CONCLUSION: While there were extractions in 25-37 per cent of all patients during the last
decades (Dausch-Neumann, 1986; Proffit, 1994), the rate of extractions is now more than
halved. Extractions are mostly prescribed in standard situations such as ALD or Class II
camouflage. The reduced rate of extractions is associated with the use of modern treatment
strategies (TADs, IER, fixed distalisation devices).
OP27 THE EFFECTS OF ORTHODONTIC TREATMENT WITH EXTRACTIONS ON THE
SKELETAL VERTICAL DIMENSION. A SYSTEMATIC REVIEW
Georgios Kouvelis1, Konstantinos Dritsas1, Ioannis Doulis1, Dimitrios Kloukos2, Theodore
Eliades3, 1Department of Orthodontics and Dentofacial Orthopedics, 251 Hellenic Air Force
V.A. General Hospital, Athens, Greece and Departments of Orthodontics and Paediatric
Dentistry, 2University of Zurich and 3University of Bern, Switzerland
AIMS: To systematically search the literature and assess the available evidence for the
effects of orthodontic treatment with extractions on the vertical dimension of the face.
MATERIALS AND METHOD: Electronic database searches of published and unpublished
literature were performed. The following electronic databases, with no language and
publication date restrictions, were searched: Medline (via Ovid and PubMed), Embase (via
Ovid), the Cochrane Oral Health Group's Trials Register and Central. Unpublished literature
was searched on ClinicalTrials.gov, the National Research Register, and Pro-Quest
Dissertation Abstracts and Thesis database. The reference lists of all eligible studies were
checked for additional studies. Two review authors performed data extraction independently
and in duplicate using data collection forms. Disagreements were resolved by discussion or
the involvement of an arbiter.
RESULTS: From the 279 articles identified by the search, and after application of the
specific inclusion and exclusion criteria, 26 studies were considered eligible for inclusion in
this systematic review. No randomized controlled trial was identified, most likely due to the
very nature of the intervention. All studies were assessed for their quality and were found to
have a poor to moderate level of evidence. Moreover, the lack of standardized protocols
precluded a valid interpretation of the actual results of the studies, i.e. a meta-analysis was
not feasible. The majority of the studies indicated that extraction treatment protocol is not
significantly associated with changes in the vertical dimension, when compared to a nonextraction protocol.
CONCLUSION: Although in most cases the level of existing evidence ranged from poor to
moderate, there is considerable agreement between studies that orthodontic treatment with
extractions in not linked to a reduction in the vertical dimension. Control of vertical dimension
might not be a justification for adopting an extraction treatment protocol.
OP28 THE EFFECT OF PREMOLAR EXTRACTION ON THE POSITION OF LOWER
THIRD MOLARS AND THEIR RELATION TO THE ALVEOLAR NERVE: A LONGITUDINAL
STUDY
Annelie Miclotte1, Jeroen Van Hevele2, Reinhilde Jacobs3, Constantinus Politis2, Guy
Willems1, 1Department of Oral Health Sciences-Orthodontics, KU Leuven & Dentistry UZ
Leuven, and KULeuven, 2OMFS IMPATH, Department of Imaging & Pathology, Faculty of
Medicine, University Leuven & Maxillofacial Surgery, University Hospitals, Leuven and
KULeuven, 3OIC, OMFS IMPATH Research Group, Department Imaging and Pathology,
Faculty of Medicine, University of Leuven and Oral and Maxillofacial Surgery, University
Hospitals Leuven and KULeuven, Belgium
AIMS: To longitudinally compare changes in lower third molar position and their relationship
to the alveolar nerve in orthodontically treated patients with and without extraction of
premolars.
MATERIALS AND METHOD: The pre- and post-treatment panoramic radiographs of 349
orthodontically treated patients subdivided into a non-extraction group (n = 263) and an
extraction group (n = 86). In the extraction group (n = 86), there were 32 males and 54
females, the mean age pre-treatment was 13 years, post-treatment 15.8 years. In the nonextraction group (n = 263), there were 136 males and 127 females, the mean age pretreatment was 12.7 years, post-treatment 15.5 years. None of the patients presented dental
agenesis in the lower jaw. The classifications of Pell and Gregory and Winter were used to
determine third molar position, and Demirjian’s classification to analyze the mineralization
status of the third molars. The relationship between the lower third molars and alveolar nerve
was assessed through Whaites’ classification. Inter- and intraobserver reliability were
investigated through Cohen’s kappa coefficient. Data was analyzed using frequency
analysis, Mann-Whitney U test, Fisher’s exact test and chi-square testing.
RESULTS: For pre-treatment panoramic radiographs, chi-square tests revealed no
significant differences between the extraction and non-extraction groups. For post-treatment
panoramic radiographs, there were significant differences between the extraction and nonextraction patients for the horizontal classification of Pell and Gregory, Winter’s classification
and for a potential relationship between the third molars and alveolar nerve (P < 0.05). In the
extraction group, 44.8 per cent of third molars did not have sufficient space to erupt after
orthodontic treatment, while in the non-extraction group the percentage was 64.5.
CONCLUSION: Orthodontic treatment with premolar extractions shows significantly less
eruption problems for third molars than those without premolar extractions. Compared to the
non-extraction group, third molars in the extraction group were less frequently found in close
relationship to the mandibular nerve.
OP29 THE DECISION TO EXTRACT PREMOLARS: ITS LONG-TERM EFFECT ON
GINGIVAL RECESSIONS IN THE LOWER ANTERIOR DENTITION
Raphael Patcas, Nicolas Villard, Clinic for Orthodontics and Pediatric Dentistry, University of
Zurich, Switzerland
AIMS: Dental crowding can be alleviated either by expanding the dental curvature [nonextraction (nonex)], by reduction of aproximal enamel, or by tooth extractions (ex), mostly
premolars. The aim of this study was to evaluate the long-term outcome of treatment choice
(non-ex versus ex) with regard to lower anterior gingival recessions. The hypothesis was that
treatment choice affects the topographical location of the lower anterior dentition and
consequently the development of recessions.
SUBJECTS AND METHOD: Fifty consecutive patients (27 females, 23 males) treated with
fixed appliances who had a defined and normally distributed moderate crowding in the initial
records and an Angle Class I malocclusion (26 non-ex, 24 ex). The patient’s age was
recorded at the beginning and end of active treatment, as well as in retention, to calculate
the time of active treatment and the time in retention. Dental casts were used to establish the
amount of crowding and the clinical crown-length of the lower canines and incisors; several
symphyseal variables were measured on cephalograms. All data were descriptively
reviewed, and potential correlations and multiple regressions were investigated.
RESULTS: To enable an accurate comparison of the ex and non-ex groups, the following
variables had to be matched by establishing no significant differences between the groups:
initial crowding (mean Little Index: 4.2 mm), duration of observed retention period (mean
retention time: 7.1 years) and age at retention survey (mean age: 24.3 years). The crownlength tended to increase over time in both groups, but not significantly, yet more than twice
as much for canines (mean ex-group: 1.1 mm, mean non-ex-group: 0.9 mm) than incisors
(mean ex and non-ex: 0.4 mm). Although treatment choice significantly altered the final
topographical location of the lower anterior dentition within the mandibular symphysis (P <
0.001), it had no impact on the development of recessions (P = 0.853). No variables could
be discerned in regression models that would predict the development of recessions.
CONCLUSION: The hypothesis has to be rejected. The tendency towards gingival
recessions observed after orthodontic treatment seems to be unrelated to the choice of
treatment (ex versus non-ex).
OP30 LONG-TERM EVALUATION OF CLASS II SUBDIVISION TREATMENT WITH
UNILATERAL MAXILLARY FIRST MOLAR EXTRACTION
Christos Livas1, Nikolaos Pandis2, Johan Willem Booij3, Christos Katsaros2, Yijin Ren1,
1
University of Groningen, University Medical Centre Groningen, Netherlands, 2University of
Bern, Switzerland and 3Private practice, Gorinchem, Netherlands
AIMS: To evaluate the long-term effects of asymmetric maxillary first molar (M1) extraction
in Class II subdivision treatment.
MATERIALS AND METHOD: The records of 20 Caucasian Class II subdivision subjects (7
boys, 13 girls; mean age, 13.0 years; SD, 1.7 years) consecutively treated with the Begg
technique and M1 extraction, and 15 untreated asymmetric Class II adolescents (4 boys, 11
girls; mean age, 12.2 years; SD, 1.3 years). Cephalometric analysis and Peer Assessment
Rating (PAR) were carried out before (T1) and after (T2) treatment and, on average, 2.5
years post-treatment (T3) for the treatment group, and at similar time points and average
follow-up of 1.8 years for the controls.
RESULTS: The adjusted analysis indicated that the maxillary incisors were 2.3 mm more
retracted in relation to A-Pog between T1 and T3 (β = 2.31; 95% CI; 0.76, 3.87), whereas
the mandibular incisors were 1.3 mm more protracted (β = 1.34; 95% CI; 0.09, 2.59), and 5.9
degrees more proclined to the mandibular plane (β = 5.92; 95% CI; 1.43, 10.41) compared
with the controls. The lower lip appeared 1.4 mm more protrusive relative to the subnasalesoft tissue-Pog line throughout the observation period in the treated adolescents (β = 1.43;
95% CI; 0.18, 2.67). There was a significant PAR score reduction over the entire follow-up
period in the molar extraction group (β = –6.73; 95% CI; 210.7, 22.7). At T2, 65 per cent of
the subjects had maxillary midlines perfectly aligned with the face.
CONCLUSION: Unilateral M1 extraction in asymmetric Class II cases may lead to
favourable occlusal outcomes in the long term without harming the midline aesthetics and
soft tissue profile.
OP31 THREE-DIMENSIONAL EVALUATION OF LONG-TERM DENTAL ARCH CHANGES
WITH AND WITHOUT PREMOLAR EXTRACTIONS
Sercan Akyalcin1, Josh Knowles1, Jeryl English1, Moody Alexander2. Wick Alexander2,
1
Department of Orthodontics, University of Texas Health Science Center, Houston and
2
Private Practice, Arlington, USA
AIMS: To evaluate and compare the longitudinal changes in dental arch form and
dimensions of orthodontic patients treated with and without four premolar extractions.
MATERIALS AND METHOD: An observational cohort included complete pre-treatment,
post-treatment and post-retention records of 107 orthodontic patients, 71 females and 36
males with a mean age of 12 years 9 months, (n = 53, extraction; n = 54, non-extraction)
with an Angle Class I malocclusion, normal vertical and sagittal skeletal growth, and no
apparent transverse discrepancy. All patients were treated with a 0.018 inch slot
contemporary fixed appliance system using a standard archwire template. Average retention
and post-retention times in the sample group were 5.2 ± 0.6 years and 13.9 ± 1.2 years,
respectively. Extraction and non-extraction groups were subdivided according to the initial
mandibular dental arch form: ovoid, tapered, and square. Three-dimensional (3D) dental
models from all time periods were acquired using a laser desktop scanner. Transverse linear
widths at the level of the canines, first premolars, and first molars were digitally measured for
all time periods. Additionally, average linear surface and arch form changes were evaluated
from pre-treatment to post-retention. The data was analyzed using a three-way analysis of
variance (ANOVA) with the main effects: treatment group, arch form, and time. Multiple
comparisons were made with the Bonferroni post hoc test. The level of significance was set
at P < 0.05.
RESULTS: Significant group*time interactions were found for mandibular canine, maxillary
and mandibular premolar and molar width measurements (P < 0.05). There were also
significant arch form*time interactions for mandibular premolar and maxillary and mandibular
molar width measurements (P < 0.05). However, group*time*arch form interaction was not
significant for any of the arch width measurements studied. Frequency of arch form changes
in the post-retention period did not differ between the extraction and non-extraction groups.
However, significant treatment and post-retention differences occurred in dental arch form
for individuals with tapered and square arch forms when compared to those with ovoid
arches (P < 0.05).
CONCLUSION: No evident difference was found between the extraction and non-extraction
groups in the long-term evaluation of dental arch dimensions. Relapse in arch form and
dimensions predominantly occurred in individuals with tapered and square arch forms
regardless of the premolar extractions.
OP32 LONG-TERM CHANGES IN THE TRANSVERSE DIMENSION OF THE SMILE IN
EXTRACTION AND NON-EXTRACTION PATIENTS
Sercan Akyalcin1, Jeryl English1, Kenner Misner1, Moody Alexander2, Wick Alexander2,
1
Department of Orthodontics, University of Texas Health Science Center, Houston and
2
Private Practice, Arlington, USA
AIMS: The effect of post-retention changes on the transverse dimension of the smile and
buccal corridors is not fully elucidated. The aim of this study was to analyse the long-term
changes in maxillary arch widths and buccal corridor ratios in an orthodontic patient
population treated with and without premolar extractions.
SUBJECTS AND METHOD: The sample group (mean age: 12.9 ± 0.6 years) comprised 28
extraction (18 females, 10 males) and 25 non-extraction (16 females, 9 males) patients with
a skeletal and dental Class I relationship, normal vertical growth pattern (26°<SN-MP <38°),
acceptable mandibular incisor inclination (88° <IMPA <100°), and no evident facial
asymmetry. All included cases were treated with 0.018 inch slot pre-adjusted edgewise
appliances and had complete orthodontic records that included pre- (T1) and post- (T2)
treatment, and post-retention (T3) study models and frontal smiling photographs. The mean
retention and post-retention times in the sample group were 4 years 1 month, and 17 years 4
months, respectively. Dental models and smiling photographs of all three time periods were
digitized to compare three dental arch width measurements and three buccal corridor ratios
between the extraction and non-extraction groups over time. The data was analysed using a
two-way analysis of variance (ANOVA). Multiple comparisons were performed with the
Bonferroni test. The level of significance was established at P < 0.05.
RESULTS: Intercanine width measurement was fairly stable in both groups over time. There
was a significant increase in interpremolar width from T1-T2 (P < 0.05) that remained stable
between T2 and T3 in both groups. Intermolar width measurement showed no significant
changes with treatment and was stable in the post-retention period for both groups. Soft
tissue extension during smiling increased with age over time (P < 0.05). The buccal corridors
showed favourable decreases with treatment in both groups (P < 0.05), and remained
virtually stable in the post-retention phase (P > 0.05). The mean difference in the buccal
corridor space of the two groups at T3 was 2.4 ± 0.2 per cent (P > 0.05). No significant
group*time interaction was identified for any of the buccal corridor ratios.
CONCLUSION: Non-extraction patients started and finished orthodontic treatment with
slightly less buccal corridor space as compared to extraction patients. The treatment
outcome was maintained at post-retention follow-up for both groups.
OP33 DO EXTRACTION CASES ACHIEVE BETTER TREATMENT RESULTS?
Dimitrios Konstantonis, Chrysi Anthopoulou, Margarita Makou, Department of Orthodontics,
University of Athens, School of Dentistry, Greece
AIMS: A controversy exists regarding better treatment outcomes when cases with
extractions and without extractions are evaluated. The aim of this study was to compare
treatment outcomes of extraction versus non-extraction Class I cases using the American
Board of Orthodontics objective grading system (ABO-OGS), and to determine whether the
treatment choice was a significant predictor of success of the ABO examination.
SUBJECTS AND METHOD: Discriminant analysis was employed in a sample of 542
patients treated in a university graduate programme and in five private orthodontic offices.
Subsequently, a borderline sample of 55 patients was obtained. Of these patients, 25 were
treated with and 30 without extraction of four first premolars. Of the extraction patients 16
were female and nine male with a mean age of 16.3 years (SD 7.84 years). The nonextraction sample consisted of 30 patients [20 females, 10 males with a mean age of 13.79
years (SD 3.99 years)]. The treatment results were then assessed using the eight variable
OGS suggested by the ABO.
RESULTS: The total score for the extraction group ranged from 11 to 41 (mean = 27.04, SD
6.3), whereas for the non-extraction group the total score ranged from 16 to 44 (mean =
29.07, SD 7.1). The variable of buccolingual inclination presented the highest score in both
groups (8.44, SD 3.3 for the extraction and 8.90, SD 3.8 for the non-extraction group; mean
difference: 0.46; 95% CI: –1.44, 2.37; P = 0.63). However, no statistically significant
intergroup differences were found either between the scores of the eight ABO-OGS
variables or between the total ABO-OGS score. Regarding the success rate of the ABO
examination, no significant difference was found between the two treatment groups (OR:
2.55, 95% CI: 0.74, 0.85; P = 0.14).
CONCLUSION: When treating a Class I borderline case the choice of extraction versus
non-extraction treatment can achieve the same quality of results as assessed by the ABOOGS. Additionally, in Class I cases the treatment modality (extraction or non-extraction) is
not a significant predictor of passing the ABO examination.
OP34 BMP-2 FUNCTIONALIZATION OF MINISCREWS INCREASES STABILITY AND
CORTICAL LEVEL BONE-TO-IMPLANT CONTACT – A HISTOMORPHOMETRIC AND
MICROCOMPUTED TOMOGRAPHIC EVALUATION
Michael Bertl1, Adriano Crismani2, Michael Rasse3, Volker Kuhn4, Rainer Biedermann2,
1
University Clinic of Dentistry, Division of Orthodontics, Medical University of Vienna, and
Departments of 2Orthodontics, 3Oral and Maxillofacial Surgery and 4Trauma Surgery,
Medical University of Innsbruck, Austria
AIMS: Sufficient cortical bone thickness has been shown to critically affect miniscrew
stability and the smaller amount of cortical bone formed at the head of the miniscrew may be
a reason for higher failure rates. BMP-2 functionalized implant surfaces have previously
been explored to enhance overall osseointegration and induce cortex-bearing bone
formation at supraalveolar peri-implant defects. The aim of this study was to investigate the
effect of a BMP-2 functionalized implant surface on the stability and cortical-level bone-toimplant contact ratio (BICR) of orthodontic miniscrews.
MATERIALS AND METHOD: Thirty six miniscrews (length: 6 mm; diameter: 1.5 mm) were
placed in three pigs. Half of the miniscrews were coated with nano crystalline diamond
(NCD) and functionalized with BMP-2. Upon insertion, stability was evaluated by measuring
resonance frequency with an Osstell ISQ wireless probe. One animal was sacrificed after 2,
4 and 12 weeks and resonance frequency analysis (RFA) was repeated. The recovered
miniscrews and surrounding bone were scanned by microcomputed tomography (μCT)
before sectioning for bright field microscopy. BICR was then evaluated in two dimensions on
histological samples and in three dimensions on μCT scans at both the cortical (head/neck)
and trabecular (thread) level of the miniscrews.
RESULTS: Stability, as expressed by increased RFA results, significantly increased for
BMP-2 functionalized miniscrews after 4 and 12 weeks. The neck/tread ratio of the two- and
three-dimensional BICR showed significantly higher cortical level bone-to-implant contact of
BMP-2 functionalized miniscrews at those timepoints. There was a positive correlation
between higher RFA results and cortical BICR.
CONCLUSION: The results suggest an increase in stability of BMP-2 functionalized
miniscrews as a result of higher BICR at the cortical bone level.
OP35 SKELETAL AND DENTAL CHANGES IN BONE- AND TOOTH-ANCHORED RAPID
MAXILLARY EXPANSION
Manuel Lagravere1, Joshua Luebbert1, Winfried Harzer2, 1University of Alberta, Edmonton,
Canada and 2University of Dresden, Germany
AIMS: To determine the skeletal and dental changes in rapid maxillary expansion (RME)
treatments using bone and tooth-anchored appliances assessed through cone-beam
computer tomography (CBCT).
SUBJECTS AND METHOD: Fifty-two patients with maxillary transverse deficiency (11-17
years old). The patients were divided into three groups, one group had a tooth-borne
expander (Hyrax; 8 males, `19 females), one group a bone-anchored expander (4 males, 10
females) and one group served as the control (9 males, 11 females). CBCTs were obtained
of each patient at two time points (initial T1 and 2.5 years post-treatment T4). CBCTs were
analyzed using Avizo software and landmarks were placed on skeletal and dental
anatomical structures on the cranial base, maxilla and mandible. Descriptive statistics,
intraclass correlation coefficients, one-way ANOVA and Bonferroni were used to determine if
there were skeletal and dental changes and if these changes were statistically different
between the groups.
RESULTS: Descriptive statistics showed that dental changes were larger than skeletal
changes in all groups. Skeletal and dental changes between groups were not statistically
different (P > 0.05) from each other between T1 and T4. At T4 there was a statistically
significant (P < 0.05) increase in vertical and antero-posterior facial dimensions.
CONCLUSION: RME treatment using bone or tooth-anchored expanders showed similar
skeletal and dental changes. These changes were greater on the dental structures
compared to the skeletal ones at a 4:1 ratio. The increase in facial dimensions continues
through adolescence post-expansion due to continued mandibular growth.
OP36 EVALUATION OF THE EFFECTS OF BONE ANCHORED MAXILLARY
PROTRACTION WITH OR WITHOUT ALTERNATE RAPID EXPANSION AND
CONSTRICTION IN THE PEAK PUBERTAL PERIOD
Berna Ertekin1, Elçin Esenlik1, Yavuz Fındık2, Hikmet Orhan3, 1Orthodontic Department,
2
Oral and Maxillofacial Surgery Department and 3Public Health Department, Suleyman
Demirel University, Isparta, Turkey
AIMS: To investigate the effects of bone anchored maxillary protraction with or without
alternate rapid maxillary expansion and constriction (Alt-RAMEC) in individuals with skeletal
Class III malocclusions
SUBJECTS AND METHOD: Thirty subjects with retrognathic maxillae in the peak pubertal
period, randomly divided into two groups. Group I consisted of 8 girls and 7 boys (mean age
12.13 ± 0.58 years) treated only with skeletal anchorage, and group II. 7 girls and 8 boys
(mean age 12.11 ± 0.59 years) treated with skeletal anchorage with the Alt-RAMEC protocol.
Treatment continued until a positive overjet was obtained. Changes in the dentoskeletal
cephalometric variables were compared in the two groups. Statistical comparisons were
performed with t-tests.
RESULTS: Treatment durations were 1.2 and 1 year in groups I and II, respectively.
Anterior displacement of the maxilla was similar for both groups (1.53 mm in group I and 1.7
mm in group II), while the protraction rate was significantly more in group II (0.15 mm per
month in group I and 0.21 mm per month in group II, P < 0.05). Mandibular and
dentoalveolar changes were similar except for the significantly more evident protrusion of the
upper incisors in group I (P < 0.05). The maxillomandibular relationship and soft tissue
profile were improved remarkably in both groups.
CONCLUSION: In subjects with maxillary retrognathia treated with skeletal anchorage in the
peak pubertal period, the treatment duration is significantly shorter and the protrusion of the
upper incisors is significantly less with the Alt-RAMEC protocol.
OP37 CXCL11 OVEREXPRESSION IN THE DISINTEGRATING MIDLINE EPITHELIAL
SEAM DURING PALATAL FUSION
Maarten Suttorp, Frank Wagener, Anne Marie Kuijpers-Jagtman, Department of
Orthodontics and Craniofacial Biology, Radboud University Medical Centre, Nijmegen,
Netherlands
AIMS: A cleft lip and/or palate (CLP) is a common facial congenital malformation. However,
the exact biological mechanisms are still not completely understood. Disintegration of the
midline epithelial seam (MES) is crucial in the mechanism of palatal fusion and is thought to
involve epithelial migration and apoptosis. Palatogenesis in the presence or absence of the
cytoprotective enzyme heme oxygenase-2 (HO-2) was studied and it was postulated that the
epithelial chemokine CXCL11 could play a decisive role in inflammation, epithelial migration,
and apoptosis.
MATERIALS AND METHOD: Foetuses of 8-10 week-old pregnant mice, 10 wildtype (wt)
and 17 HO-2 KO, were obtained. After sacrifice of the animals at day 15 (E15), the placentas
and organs of the foetuses were isolated. Immunohistochemical staining of the palatal
structures was performed using antibodies against HO-1, CXCL11, and its receptor CXCR3,
epithelial marker pan-keratin, and a FragEL-apoptosis kit. RNA was isolated from the
craniofacial region of 5 wt and 4 HO-2 KO foetuses.
RESULTS: HO-2 mRNA expression was present in wt but absent in HO-2 KO animals.
More HO-1 positive macrophages were present in the mesenchyme of the palatal shelves of
HO-2 KO foetuses when compared to wt. This is the first study, demonstrating a specific
statistically significant overexpression of CXCL11 in the epithelial cells of the disintegrating
MES during palatal fusion, while CXCR3 was more generally present in the palatal
epithelium of both genotypes.
CONCLUSION: No difference in palatogenesis was detected between HO-2 KO and wt
animals, suggesting that HO-mediated protection is mainly crucial in the presence of
excessive inflammatory insults. The striking overexpression of CXCL11 in the disintegrating
MES during palatal fusion suggests a prominent role for chemokines and chemokine
receptors during palatogenesis.
OP38 EVALUATION OF SECONDARY ALVEOLAR BONE GRAFTED PATIENTS BORN
WITH A CLEFT LIP AND PALATE – A LONG-TERM FOLLOW-UP STUDY
Mathias Lemberger1,2, Hedieh Setayesh2, Petra Peterson3, Anna Andlin-Sobocki4, Agneta
Karsten1,2, 1Department of Orthodontics, 2Karolinska Institutet, Stockholm, 3Department of
Plastic and Reconstructive Surgery, Karolinska University Hospital, Stockholm and
4
Emeritus, Stockholm, Sweden
AIMS: To investigate the treatment outcome of secondary alveolar bone grafting in patients
born with alveolar clefts.
SUBJECTS AND METHOD: Twenty-one consecutive patients (18 males, 3 females) born
with a unilateral cleft lip and palate. The alveolar clefts were grafted with autologous bone
from the iliac crest when the children were 8 to 11 years of age. At 18 years of age the
patients were clinically and radiographically examined in the cleft region. Inter-dental septum
height was evaluated according to the Bergland index. Periodontal conditions were
assessed using the gingival index (Löe and Silness, 1963), probing depth, tooth mobility and
gingival recessions. The contralateral non-cleft side in the same patient (split mouth design)
served as the control. One investigator performed all measurements.
RESULTS: Twenty-one patients were followed up 5.5-10.5 years after secondary alveolar
bone grafting with an average follow-up time of 8.5 years. The mean age of the subjects was 19
years 6 month at the radiographic examination (range 17 years 6 month to 20 years 11 months). The
mean age at the clinical examination was 20 years with a range of 19 years 1 month to 21 years 2
months. Normal interdental septal height was seen in 62 per cent and a slight decrease in 19
per cent. Nineteen per cent had an interdental septum bone height less than three-quarters
of normal. There were no differences regarding gingival index and probing depth between
the cleft side and non-cleft side teeth. Twenty-four per cent of patients had increased tooth
mobility on one tooth or more on the cleft side, and one patient had increased mobility on
both sides. One patient showed mobility on the control side. Gingival recessions adjacent to
the cleft were seen in 48 per cent of patients. They were seen more frequently on the cleft
side.
CONCLUSION: Teeth adjacent to a reconstructed alveolar cleft tended to have inferior
periodontal tooth support compared with control sites in this long-term follow-up study.
OP39 ORAL CLEFTS AND WOUND HEALING: THE ROLE OF FIBRONECTIN IN
MYOFIBROBLAST DIFFERENTIATION
Joël Beyeler, Christos Katsaros, Matthias Chiquet, Department of Orthodontics and
Dentofacial Orthopedics, University of Bern, Switzerland
AIMS: A fraction of patients with cleft lip and/or palate (CLP) undergoing primary surgery
develop excessive scars that impede maxillary growth. It has recently been shown that
fibroblasts from a distinct subgroup of CLP patients exhibit an increased migration rate into
wounds in vitro (Beyeler et al., PlosOne, 2014). The persistence of myofibroblasts in healing
wounds is believed to be the cause of excessive scarring and wound contracture. The
glycoprotein fibronectin (FN) is an essential extracellular matrix (ECM) molecule mediating
numerous biological events during development and wound repair. Since FN links the cells’
integrin receptors to other components of the ECM (e.g. collagens), it was speculated that
FN promotes myofibroblast differentiation by mediating efficient spreading on a threedimensional (3D) collagen matrix.
MATERIALS AND METHOD: To test the functions of FN in cell spreading, collagen matrix
contracture and myofibroblast differentiation, FN wildtype (FN+/+) and FN knockout (FN-/-)
mouse embryonic fibroblasts (MEFs) were seeded on 3D fibrillar collagen gels (1.5 mg/ml) in
the presence and absence of exogenous FN. Cell spreading was morphometrically
evaluated over time. Collagen gel contracture was quantified by measuring the area after 24
hours detachment of the gel from the walls of the culture well relative to the initial area.
Assembly of FN, α5-integrin positive fibrillar adhesions, and expression of the specific
myofibroblast marker α-smooth muscle-actin (α-SM-actin) were visualized by
immunofluorescence staining.
RESULTS: In contrast to FN+/+ MEFs, FN-/- cells barely spread on the collagen gel after 3
hours of incubation under FN-free conditions. Cell spreading was restored in the presence of
exogenous FN. Collagen gel contracture by FN-/- MEFs was negligibly small compared to
FN+/+ cells, and was partially rescued on collagen gels coated with exogenous FN.
Similarly, FN-/- MEFs lacked expression of α-SM-actin and integrin α5-positive fibrillar
adhesions under FN-free conditions, which were reversed to some extent by exogenous FN.
CONCLUSION: Using FN-/- fibroblasts a direct correlation between the presence of FN, cell
spreading on a 3D collagen matrix, and myofibroblast differentiation has been shown for the
first time. Thus FN could contribute to the persistence of myofibroblasts in wound healing.
OP40 BEYOND ORTHODONTICS: OPPORTUNISTIC PATHOGENS ASSOCIATED WITH
ORTHODONTIC RETAINERS
Dheaa Al-Groosh1, Jonathan Pratten2, Nigel Hunt2, 1College of Dentistry/University of
Baghdad, Iraq and 2UCL Eastman Dental Institute, London, U.K.
AIMS: This prospective cohort study was designed to evaluate the carriage state of
opportunistic pathogens i.e. staphylococci and Candida species, after removal of fixed
orthodontic appliances and during the retention phase.
SUBJECTS AND METHOD: Twenty-two patients who experienced orthodontic treatment (8
males, 14 females) with an age range between 16 and 32 years, and 11 control subjects.
The patients were divided into three subgroups according to the treatment stage; just before
bracket removal (T0). 1 week after bracket debond and without retainers (T1) and full-time
retainer wearers after 3 months of wear (T2). Eight microbiological samples were collected
from each subject including saliva, plaque samples and six swab samples (from the palate,
cheek and tongue, nose, skin of the hand, skin of the face and the fitting surface of the
removable retainers). The samples were analysed using different microbiological and
molecular methods.
RESULTS: There was a significant (P < 0.001) increase in the number and percentage of
positive sites of Staphylococcus and Candida spp. in all study groups compared to nonorthodontic cohorts. The percentage of positive sites for methicillin-resistant staphylococcus
aureus (MRSA) was higher in the orthodontic appliance, plaque and the mucosa of the
check and tongue in the retention group.
CONCLUSION: The microbial population associated with removable orthodontic retainers
has revealed a startling change in normal oral microbiota with the detection of opportunistic
pathogens such as MRSA.
OP41 SATELLITE CELLS FROM HEAD MUSCLES FORM FUNCTIONAL MYOFIBRES IN
VITRO
Paola Carvajal Monroy, Frank Wagener, Hans Von den Hoff, Department of Orthodontics
and Craniofacial Biology, Radboud university medical center, Nijmegen, Netherlands
AIMS: Surgical closure of a soft palate cleft often fails to allow normal speech development.
This is mainly due to fibrosis in the reconstructed muscles of the levator veli palatini (LVP).
Fibrosis may be prevented by the implantation of muscle stem cells, satellite cells (SCs), in
the surgical wounds. The aim of this study was to isolate SCs from three different head
muscles and compare their functional differentiation in vitro.
MATERIALS AND METHOD: SCs were isolated from the masseter (Ms), digastricus (Dig),
and LVP muscles of 5-week-old Wistar rats by enzymatic digestion. SCs (1250) were
seeded onto 2 mm spot coatings of Matrigel. The SCs were cultured for 5, 7, and 10 days to
monitor differentiation by immune staining (Pax7, MyoD, MyoG) and myofibre formation.
Data were analyzed by one-way ANOVA.
RESULTS: At day 5, about 95 per cent of all cells contained the SC marker Pax7 and the
activation marker MyoD. The fraction of Ms-SCs containing the differentiation marker MyoG
was larger than that of the Dig- and LVP-SCs (30% versus 3%) but increased to about 60
per cent at day 7. At the end of culture (day 10), only 10 per cent of all cells were Pax7 and
MyoD positive. MyoG expression was also strongly decreased. Approximately 40 per cent of
the culture area was covered with mature myofibers for all three cell types. Some of the
myofibers showed spontaneous contractions.
CONCLUSION: Highly potent SCs can be isolated from all three head muscles and form
functional myofibers in vitro. Ms cells seem to differentiate earlier than the others but in the
end all SCs form similar amounts of myofibers. Ms-SCs might be most suitable for cleft
palate therapy since biopsies from the Ms can be easily obtained. Further research will focus
on suitable hydrogels as a carrier for implantation of SCs.
OP42 POST-EMERGENT TOOTH ERUPTION OF UNOPPOSED MOLARS IN YOUNG
AND ADULT RATS. A COMPARATIVE GENE EXPRESSION ANALYSIS
Domna Dorotheou, Thanos Halazonetis, Vanessa Farsadaki, Marie-Luce Piallat-Bochaton,
Stavros Kiliaridis, University of Geneva, Switzerland
AIMS: Tooth eruption is a developmental, physiologic, locally regulated process. It can be
divided into two discernible phases, pre- and post-emergent, when the tooth has penetrated
the oral mucosa. In the post-emergent phase it has been shown that teeth after loss of
antagonists present overeruption of different degrees. The aim of this study was to elucidate
the different eruption patterns between young and adult rats at the molecular level by
comparing the gene expression of the periodontal ligament (PDL).
MATERIALS AND METHOD: Forty five male rats, 23 young (4 weeks old) and 22 adults (22
weeks of age). In 27 animals the right maxillary molars were cut down (14 young and 13
adult), the rest of the rats were served as controls. The animals were sacrificed and PDL
samples were isolated from the first mandibular molars on two occasions, 3 and 15 days
after cutting down of the right maxillary molars. Comparative cDNA microarray analysis was
performed to detect differences in gene expression between the PDL tissues of unopposed
molars and molars with antagonists in young and adult rats. These findings were verified by
Nanostring nCounter Expression Analysis in 50 genes and the areas where genes
expressed were revealed by immunohistochemical staining for 3 out of the 50 genes.
RESULTS: The expression of seven genes, Adamts18, Pth1R, Panx3, Tnmd, Ostn, P4ha3
and Postn was upregulated in unopposed molars relative to molars with antagonists, mostly
in young animals compared to adults. These genes are involved in bone formation, in
extracellular matrix (ECM) remodelling and in smooth muscle contraction processes.
CONCLUSION: The overeruption of unopposed molars is associated with upregulation of
gene expression linked to bone formation of the alveolus, in ECM remodelling of the PDL,
and in myofibroblast differentiation.
OP43 NATURAL KILLER CELLS PARTICIPATE IN ORTHODONTIC TOOTH MOVEMENT
Omer Fleissig, Ariella Glassner, Jonathan Enk, Ofer Mandelboim, Stella Chaushu, Hebrew
University, Jerusalem, Israel
AIMS: Orthodontic tooth movement (OTM) is a sterile-inflammation based process in which
immune-cells are involved, however, little is known about their type and function. Activated
NK cells (NKs) are major secretors of TNFα and IFNγ cytokines, which were shown to be
involved in OTM by promoting differentiation and activation of osteoclasts which enable OTM
through bone-resorption. The main activating-receptors of mice NKs are Ncr1 and NKG2D. It
was hypothesized that NKs participate in OTM's inflammatory-process and therefore, the
aim was to investigate the direct in vivo role of NKs, their Ncr1 and NKG2D-receptors and
secreted-cytokines in OTM.
MATERIALS AND METHOD: Nickel titanium closed-coil-springs were set between the
upper left first molar (ULM1) and the upper incisors of C57BL/6 mice in a wild-type (WT)
control group and seven experimental groups for 12 days: NKs-depleted, Ncr1-KO (Knock
out, both copies of Ncr1-gene replaced with GFP), Ncr1-het (heterozygous-one copy of
Ncr1-gene replaced with GFP), NKG2D-blocked in WT-mice (WT/NKG2D-bl), NKG2Dblocked in Ncr1-KO-mice (Ncr1-KO/NKG2D-bl), TNFα-KO and IFNγ-KO. A split-mouth
technique was used, in which the diastema between ULM1-ULM2 was measured using a
microcomputer tomographic scanner. The mice's maxillae were prepared for histology. The
in vivo accumulation of NKs in the periodontal ligament (PDL) could be evaluated with the
GFP-presence in Ncr1-het mice. NK and osteoclast numbers and location were evaluated
using immuno-fluorescence and tartrate resistant acid phosphatase staining. The presence
of ligands for Ncr1 and NKG2D receptors on the surface of the mice fibroblasts was checked
by fluorescence-activated cell sorting analysis.
RESULTS: The number of GFP-labelled-NKs significantly increased in the PDL of treatedteeth in comparison with the contralateral-side (3.44, P < 0.05). OTM was significantly
reduced in NKs-depleted, Ncr1-KO, Ncr1-KO/NKG2D-bl, TNFα-KO and IFNγ-KO groups
(1.49; 1.22; 4.31; 3.30; 2.25 fold change, respectively, P < 0.05), compared with WT.
Osteoclast numbers correlated with the ULM1-ULM2 distance in all groups (P < 0.05).
FACS-analysis revealed ligands for Ncr1 and NKG2D-receptors on the surface of mice
fibroblasts.
CONCLUSION: NKs accumulate in the PDL in response to orthodontic force and participate
in OTM in mice through their Ncr1 and NKG2D activating-receptors. Absence of NKs, Ncr1
and NKG2D-receptors, TNFα and IFNγ significantly reduced the rate of OTM. Mice
fibroblasts express ligands for Ncr1 and NKG2D-receptors. Understanding the immune
mechanisms involved in OTM will contribute in the development of novel biological
therapeutic means to clinically control it.
OP44 THE LONG-TERM SKELETO-DENTAL EFFECTS OF INTRUSION OF THE
MAXILLARY POSTERIOR TEETH IN OPEN BITE PATIENTS
Oyku Dalci1, Riaan Foot1, Ayse Bilgin2, Nour Eldin Tarraf 1, M Ali Darendeliler1, 1Department
of Orthodontics, University of Sydney and Department of Statistics, Macquarie University,
Sydney, Australia
AIMS: To evaluate the stability of open bite treatment 3.5 years post-intrusion of the upper
posterior teeth using miniscrews and the Sydney intrusion spring (SIS).
SUBJECTS AND METHOD: Sixteen adolescent patients (12 females, 4 males) with an
initial average age of 13.1 years (range 12.2 to 14.3 years). All patients were in the
permanent dentition with an anterior open bite of ≥2 mm. Four self-drilling miniscrews were
placed in the posterior maxillary buccal alveolar bone. The intrusion appliance consisted of a
bonded acrylic appliance and the SIS, activated to produce an initial intrusive force of 500 g
on the right and left sides. Cone beam computed tomograms were taken after miniscrew
placement, at the end of active intrusion and 3.5 years post-intrusion. Rendered lateral
cephalograms were produced for measuring dentoskeletal alterations. Statistical
comparisons were performed using ANOVA.
RESULTS: Open bite correction was achieved after 4.91 months (range 2.5 to 7.75 months)
of active intrusion. The mean molar intrusion was 2.9 ± 0.8 mm (P < 0.001), resulting in an
increase of overbite of 3.0 ± 1.5 mm (P < 0.001). The intrusion led to a 2.6 ± 1.3 degree (P <
0.001) clockwise occlusal plane rotation and 1.2 ± 1.3 degrees (P < 0.01) counter-clockwise
rotation of the mandible. Dental measurements showed a significant uprighting and
elongation of the incisors. There was no significant extrusion of the lower molars. At follow
up evaluation at 3,5 years, the average overbite was 1.49 ± 1.64 mm and only two of the
patients had a negative overbite (0.5 and 1.3 mm), which showed about 85 per cent
success. Upper molar intrusion was stable and the ANB angle decreased from an initial
average of 5.3 degrees to 3.8 degrees at the end of the 3.5 years post-intrusion period.
CONCLUSION: The SIS is an effective appliance for intrusion of the maxillary posterior
teeth, in conjunction with miniscrews. Post-intrusion stability is comparable to surgical
correction of skeletal open bites.
OP45 POST-TREATMENT CHANGES DURING PERMANENT RETENTION – ARE
RETAINERS RELIABLE?
Michael P Wolf 1, Ulrike Schulte1, Katharina Küpper1, Ludgar Keilig2, Andreas Jäger1,
1
Department of Orthodontics and 2Oral Technology, University of Bonn, Germany
AIMS: Permanent retention is currently the method of choice to provide effective and
reliable stabilization of orthodontic treatment outcomes. Recently, there has been
accumulating evidence of post-treatment changes under permanent retention procedures
with unclear aetiology which might even lead to the necessity of re-treatment. In the light of
prolonged retention periods, a better understanding of factors contributing to post-treatment
stability and its failure despite permanent retention is desirable. In this study the question of
how post-treatment changes might occur despite permanent retention and whether the
retainer itself might contribute to the development of a new malocclusion were addressed. A
further aim was to identify diagnostic parameters which might serve for prevention.
SUBJECTS AND METHOD: Sixty orthodontic patients (37 females, 23 males, ~19.49 years
of age) stabilized either exclusively with 3-3 bonded retainers in the lower arch (n = 30) or in
combination with removable appliances (n = 30). Plaster models at the end of treatment and
after ≥6 months’ retention were digitized, superimposed and analyzed for changes in tooth
position in all three dimensions (x-, y-, z-axes for rotation/translation) using surface analysis
software. Observed changes were correlated with pre-treatment characteristics (crowding,
intercanine width, overjet, and overbite) to identify possible treatment related risk factors.
Furthermore, the potential benefit of an additional removable appliance was evaluated.
RESULTS: Fourteen per cent of patients with bonded retainers exhibited obvious changes
in tooth position in the lower arch. The highest rate of malposition was recorded for canines
showing bucco-lingual tipping and mesio-distal translation with a centre of rotation at the
central incisors. Severe post-treatment changes were significantly correlated with expansion
of intercanine width and pronounced correction of overjet during active treatment. No
correlation with the extent of initial crowding or overbite was found. An additional use of
removable appliances reduced these striking features.
CONCLUSION: An increase of intercanine width and the extent of sagittal correction might
represent risk factors jeopardizing post-treatment stability following permanent 3-3 retention.
In selected cases, additional retention procedures might be required. Permanent retainers
themselves seem to be able to induce post-treatment changes different from the initial
malocclusion.
OP46 DO PATIENTS WITH DIFFERENT CRANIOFACIAL PATTERNS GROW
DIFFERENTLY?
Alexios Katsadouris,: Demetrios Halazonetis, Department of Orthodontics, National and
Kapodistrian University of Athens, Greece
AIMS: The question of whether patients with different skeletal discrepancies grow differently
is biologically interesting but also important in designing clinical trials. The aim of this
research was to evaluate if growth direction depends on the initial craniofacial pattern.
MATERIALS AND METHOD: Ninety lateral cephalograms of 45 subjects (22 females, 23
males) followed during normal growth without orthodontic treatment. The examined ages
were 12 and 14 years. The cephalograms were obtained from the American Association of
Orthodontists Foundation (AAOF) Craniofacial Growth Legacy Collection (Iowa and Fels
growth studies). Fifteen curves on each cephalogram, comprehensively covering the
craniofacial skeleton, were digitally traced and 127 points were located on the curves, 118 of
which were sliding semi-landmarks and nine fixed. Procrustes Alignment and Principal
Component Analysis (PCA) were performed, after sliding the semi-landmarks to minimize
bending energy.
RESULTS: The first 12 principal components (PCs) described 80 per cent of total shape
variance. PC1 was related to shape variance in the vertical direction (low/high angle skeletal
pattern) and PC2 was mainly related to shape variance in the anteroposterior direction
(Class II/Class III pattern). All subjects shared a similar growth trajectory in shape space. No
correlation was found between the initial shape and the magnitude of shape change
between the two time points. The direction of shape change was moderately correlated to
the initial value of PC2 (multiple linear regression: adjusted R2 = 25%, P = 0.023). The initial
values of the remaining PCs were not related to the growth vector in shape space.
CONCLUSION: The initial shape of the craniofacial complex was weakly correlated to
shape change during growth. Subjects differing in the anteroposterior direction may exhibit
different growth patterns.
OP47 CLINICAL IMPLICATIONS OF THE DISSIMILARITY BETWEEN MANDIBULAR
GROWTH PATTERN AND STATURAL GROWTH PATTERN
Raphael Patcas1, Timo Peltomäki2, Goran Markic1, 1Department for Orthodontics and
Pediatric Dentistry, Center of Dental Medicine, University of Zurich, Switzerland and 2Oral
and Maxillofacial Unit, Department of Ear and Oral Diseases and Department of
Otolaryngology, Tampere University Hospital and University of Tampere, Finland
AIMS: Condylar and statural (i.e. body height) growth have similar, but not identical growth
curves. The aim of this study was to compare both growth curves in untreated subjects at
different ages and investigate if any clinically relevant dissimilarity could be discerned.
SUBJECTS AND METHOD: Four hundred and eighteen untreated, healthy children (193
girls; 225 boys) from a craniofacial growth study were analyzed semi-longitudinally
(cephalograms and body height). Yearly incremental changes of three mandibular
measurements from articulare and three from condylion were compared to yearly statural
growth changes separately. The mandibular measurements (from articulare and condylion)
included symphyseal and gonial distances.
RESULTS: Mandibular growth spurt could be observed in all six different mandibular
measurements, but distances from condylion were more informative. Gonial measurements
were not as indicative as symphyseal distances. Statural peak velocity could be established
at around 12 years of age for girls and 14 years of age for boys. Mandibular growth,
however, did not coincide with somatic growth precisely, and condylar peak velocity
preceded statural peak velocity in boys by nearly 1 year (i.e. at 13 years of age) and was
delayed in girls on average around 9 months (i.e. at 12-9 years of age).
CONCLUSION:
For growth-related mandibular measurements, condylion should be
preferred over articulare, and symphyseal distances over gonial distances. When planning
growth-related orthodontic treatment, it is essential to realize that mandibular growth does
not coincide with statural growth.
OP48 MAXILLARY MOLAR DISTALIZATION IN NON-GROWING PATIENTS WITH
CLEAR ALIGNERS: A RETROSPECTIVE CASE-CONTROL STUDY
Gabriele Rossini, Tommaso Castroflorio, Andrea Bargellini, Andrea Deregibus, Cesare
Debernardi, Specialization School of Orthodontics, University of Turin - CIR Dental School,
Italy
AIMS: To evaluate, in a retrospective case-control study, the dentoskeletal effect of
sequential molar distalization obtained with clear aligners.
MATERIALS AND METHOD: One hundred and two lateral cephalograms obtained from 30
non-growing subjects (14 males, 16 females; average age 29.7 ± 4.3 years), who underwent
bilateral distalization of their maxillary dentition, and from an untreated control group of 21
subjects (12 males, 11 females, mean age 25.4 ± 3.3 years). The Wilcoxon signed-rank test
was used to analyze differences between pre- and post-treatment dental and skeletal
matched variables of the two groups, while the Mann-Whitney test for unpaired data was
used to evaluate differences between the two groups. The confidence interval was set at 95
per cent. Non-parametric tests were selected since the study population cannot be assumed
to be normally distributed. The size of the combined method error was calculated according
to Dahlberg’s formula.
RESULTS: Statistical analysis showed a significant distalization movement of the upper first
and second molars (P < 0.001) with an average bodily movement of about 2 mm. At the
same time a significant intrusion movement of about 1 mm was observed for the upper first
and second molars (P < 0.05). No significant tipping movements were registered. During
distalization, good control of upper incisor torque was revealed. No significant changes of
skeletal divergence were observed at the end of the distalization phase.
CONCLUSION: Clear aligners seem to be able to control distal bodily movement of the
upper molars without tipping and with control of the posterior vertical dimension, thus
permitting the correction of Class II molar relationships in adult patients.
OP49 34 YEARS OF AUTOTRANSPLANTATION – SUCCESS AND FAILURES
Stefan Abela1, Linda Murtadha2, Dirk Bister1, Jerry Kwok3, Departments of 1Orthodontics,
2
Oral Health and 3Oral Surgery, Guy's and St Thomas' NHS Foundation Trust, London, U.K.
AIMS: To retrospectively evaluate the success rate of autotransplantation of teeth during
various stages of orthodontic treatment, over 34 years
SUBJECTS AND METHOD: The sample of patients were treated at Queen Mary's Hospital,
Sidcup, Kent, UK, during the period 1969-2003. A total of 366 teeth were transplanted in 314
patients (203 females, 111 males, aged 10 to 58 years).
RESULTS: Seventy eight per cent of transplanted teeth were canines and the mean age of
the patients was 18 years. A long-term success rate of 97.3 per cent with a mean follow-up
period ranging between 3 weeks to 29 years was observed. Failure of treatment included 10
teeth which were lost due to failure of periodontal ligament regeneration and a persistent
mobility greater than grade III. Apical pathology was only observed in 16 per cent of all
autotransplanted teeth. In 79 per cent of this subgroup apical pathology was evident in the
first 3 years post-operatively whilst in 70 per cent, external resorption occurred within the first
3 years. Internal resorption is rare but its occurrence is usually noticed in the period between
the second and sixth year post-transplantation. Fourteen per cent of transplanted teeth
needed root canal therapy and this was completed within the first 6 months posttransplantation.
CONCLUSION: Autotransplantation is a fully justified procedure with excellent success
rates. In selected cases the possibility of autotransplantation is an alternative to orthodontic
or prosthetic treatment, including implant insertion, when restoring edentulous spaces in the
dental arches.
OP50 COMPARISON OF TWIN BLOCK VERSUS FORSUS APPLIANCE: A
CONTROLLED STUDY
Andrea Vangelisti, Veronica Giuntini, Caterina Masucci, Nicolò Defraia, Lorenzo Franchi,
Department of Surgery and Translational Medicine, University of Florence, Italy
AIMS: To compare the dentoskeletal changes produced by the Twin-Block (TB) appliance
followed by fixed appliances versus the Forsus fatigue resistant device (FRD) in combination
with fixed appliances in growing patients with a Class II division 1 malocclusion.
SUBJECTS AND METHOD: Twenty eight Class II patients (19 females, 9 males, mean age
12.4 years) treated consecutively with the TB followed by fixed appliances were compared to
a group of 36 patients (16 females, 20 males, mean age 12.3 years) treated consecutively
with the FRD in combination with fixed appliances. The two treated samples were also
compared to a control group of 27 subjects with untreated Class II malocclusions (13
females, 14 males, mean age 12.2 years) selected from the University of Michigan Growth
Study, the Denver Child Growth Study, and the Bolton-Brush Growth Study. The mean
observation interval was 2.3 years in all groups. Pre-treatment the majority of the subjects in
the three groups were at puberty (stage 3 in cervical vertebral maturation) while posttreatment (end of comprehensive treatment), all subjects were in a post-pubertal stage of
skeletal development. Cephalometric changes were compared among the three groups by
means of ANOVA and Tukey’s post-hoc tests.
RESULTS: The FRD produced significant restraint of the maxilla compared to the TB and
control groups (SNA, –1.1 and –1.8°, respectively). The TB sample exhibited significantly
greater mandibular advancement and greater increments in total mandibular length than
both the FRD and control groups (SNB, 1.9 and 1.5°, respectively, and Co-Gn, 2.0 and 3.4
mm, respectively). The FRD produced a significantly greater amount of proclination of the
lower incisors than the TB and control samples (2.9 and 5.6°, respectively).
CONCLUSION: The TB appliance produced greater skeletal effects in terms of mandibular
advancement and growth stimulation with respect to the FRD, the latter producing significant
proclination of the lower incisors. The TB appliance appears to be indicated in Class II
patients in whom mandibular skeletal effects have to be maximized.
OP51 EVALUATION OF THE LONG-TERM RESULTS OF FACEMASK THERAPY IN
CLASS III PATIENTS
Servet Dogan, Orthodontic Department, Ege University School of Dentistry, Izmir, Turkey
AIMS: Where the prevalence of maxillary deficiency is high in the aetiology of Class III,
protraction of the maxilla would be the treatment of choice. However, patients who receive
early orthopaedic treatment could still require surgical treatment at the end of the growth
period. The aim of this present research was to determine the short- and long-term progress
of patients treated with facemask therapy.
SUBJECTS AND METHOD: Forty five patients (23 females, 22 males) divided into two
groups according to age. (Group 1: aged between 8-10 years, group 2: aged between 11-14
years). Clinically, all the patients had a concave facial profile, retrusive nasomaxillary area,
and prominent lower third of the face. The lower lip was often protruded relative to the upper
lip. The upper arch was usually much narrower than the lower arch, and the overjet and
overbite ranged from reduced to reversed. All patients were instructed to wear their
facemasks at least 16 hours per day. This was continued until at least a 4 mm overjet was
achieved. Cephalometric films taken pre- and post-treatment and approximately 8 years
post-treatment were evaluated with a Student’s t-test.
RESULTS: Anterior displacement of the maxilla, forward movement of the maxillary
dentition and downward and backward rotation of the mandible were the effects of facemask
treatment for the two groups (P < 0.001). Anterior displacement and counterclockwise
rotation of the maxilla, downward and backward rotation of the mandible, forward movement
of the maxillary dentition and retroclination of the mandibular incisors were more pronounced
in the young group (P < 0.001). Lower anterior face height increased while overbite
decreased in the two groups (P < 0.001).
CONCLUSION: Facemask therapy is an effective approach for skeletal Class III patients
with maxillary deficiency. Treatment in the primary or early mixed dentition produces greater
skeletal changes in a short time; treatment in the late mixed dentition or early permanent
dentition also produces positive results. The effects of genetic factors on aetiology, the
severity of malocclusion, the direction of growth, age, good interdigitation at the end of
treatment and no growth rate at the end of post-retention, are the most important factors for
successful treatment.
OP52 EVALUATION OF A THREE-DIMENSIONAL SUPERIMPOSITION TECHNIQUE ON
DIFFERENT SKELETAL STRUCTURES OF THE HEAD USING SURFACE MODELS
Nikolaos Gkantidis1, Michael Schauseil2, Berna Zorkun3, Christos Katsaros1, Björn Ludwig4,
1
Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Switzerland,
Departments of Orthodontics, 2University of Marburg, Germany, 3Cumhuriyet University,
Sivas, Turkey and 4University of Saarland, Homburg/Saar, Germany
AIMS: To test the applicability, accuracy, precision, and reproducibility of various threedimensional (3D) superimposition techniques for radiographic data, transformed to
triangulated surface data.
MATERIALS AND METHOD: Five superimposition techniques (3P: three-point registration;
AC: anterior cranial base; AC + F: anterior cranial base + foramen magnum; BZ: both
zygomatic arches; 1Z: one zygomatic arch) were tested using eight pairs of pre-existing
computed tomographic data (pre- and post-treatment). These were obtained from nongrowing orthodontic patients treated with rapid maxillary expansion. All datasets were
superimposed by three operators independently, who repeated the whole procedure one
month later. Accuracy was assessed by the distance (D) between superimposed datasets on
three form-stable anatomical areas, located on the anterior cranial base and the foramen
magnum. Precision and reproducibility were assessed using the distances between models
at four specific landmarks. Non-parametric multivariate models and Bland-Altman difference
plots were used for analyses.
RESULTS: There was no difference among operators or between time points on the
accuracy of each superimposition technique (P > 0.05). The AC + F technique was the most
accurate (D < 0.17 mm), as expected, followed by AC and BZ superimpositions that
presented similar level of accuracy (D < 0.5 mm). 3P and 1Z were the least accurate
superimpositions (0.79 < D < 1.76 mm, P < 0.005). Although there was no difference among
operators or between time points on the precision of each superimposition technique (P >
0.05), the detected structural changes differed significantly between different techniques (P
< 0.05). Bland-Altman difference plots showed that BZ superimposition was comparable to
AC, though it presented slightly higher random error.
CONCLUSION: Superimposition of 3D datasets using surface models created from voxel
data can provide accurate, precise, and reproducible results, offering also high efficiency
and increased post-processing capabilities. In the present study population, the BZ
superimposition was comparable to AC, with the added advantage of being applicable to
scans with a smaller field of view.
OP53 DEBONDING OF POLYCRYSTALLINE CERAMIC BRACKETS WITH A
ER,CR:YSGG LASER: A NOVEL TECHNIQUE
Collin Jacobs1, Ambili Mundethu1, Rene Franzen2, Norbert Gutknecht3, Heiner Wehrbein1,
Department of Orthodontics, University of Mainz, 2AALZ and 3Department of Restorative
Dentistry, University of Aachen, Germany
AIMS: Debonding of ceramic brackets involves the risk of enamel fracture. The aim of this
study was to investigate the applicability of an erbium, chromium doped yttrium scandium
gallium garnet (Er,Cr:YSGG) laser for debonding ceramic brackets.
MATERIALS AND METHOD: Three adhesive systems (Blugloo, Ormco; Transbond, 3M
Unitek and Bonding Resin, Reliance Orthodontic Products) were each used to bond ceramic
brackets [Glam (GL), Forestadent; Clarity (C), 3M Unitek and Damon Clear (DC), Ormco] on
human teeth in vitro (n = 90, n = 5 per group). With an Er,Cr:YSGG laser, laser impulses
were directed perpendicularly through the bracket slot. A laser setting of 6 Watts, 10 Hz in Hmodus (100 µs) was chosen for the study. Debonding was controlled optically and under
time measurements. Increases of temperature in the pulp were measured with a
thermocouple and the transmission through brackets with a parameter. The adhesive
remnant index (ARI) was assessed with light microscopy. Enamel surfaces were analyzed
by electron microscopy.
RESULTS: The debonding rate differed between bracket types (DC: 100%, GL: 0%, C:
20%); the average debonding time of DC was 0.5 ± 1.0 seconds. Transmission of brackets
showed significant differences (DC: 56.8%, GL: 53.6%, C: 20%). No significant increase of
temperature in the pulp was observed under water and air cooling. The ARI for Transbond,
Blugloo and Bonding Resin was 3.0, 3.0 and 2.5, respectively. Electron microscopic analysis
showed only for Bonding Resin a partially affected enamel surface.
CONCLUSION: Debonding of ceramic brackets with an Er,Cr:YSGG laser is possible by
directing laser impulses through the bracket slot. A combination of DC brackets with Blugloo
or Transbond represents the ideal combination for Er,Cr:YSGG debonding.
OP54 THERAPEUTIC EFFECTS OF HIGH-FREQUENCY ACCELERATIONS ON
ALVEOLAR BONE DENSITY IN OSTEOPOROTIC RATS
Joo Young Nho, Kendrick Park, Dayoon Lee, Tatiana Hladkaya, Department of Dentistry,
New York University, New York, USA
AIMS: To investigate the regenerative effect of high-frequency acceleration (HFA) on
alveolar bone of osteoporotic rats.
MATERIALS AND METHOD: A total of 80 female Sprague-Dawley rats, aged 120 days,
were randomly divided into four groups: 1) Overectomized (OVX), 2) Sham that received
similar surgery without overectomy 3) low mineral diet (LMD) that received a lower mineral
diet without and surgery, and 4) control. All animals (except the control group) were exposed
to a lower mineral diet for 3 months. Osteoporosis was confirmed with bone density
measurement of the fifth lumbar vertebra. The experimental groups were exposed to HFA for
5 minutes per day applied on the upper left maxillary teeth and samples were collected at 28
and 56 days. At the end of the each time point, animals were sacrificed and maxillae were
harvested for microcomputed tomography (μCT), histology analysis, fluorescent, FTIR
microscopy, protein and RNA analysis. Comparisons between groups were assessed by
analysis of variance. Pairwise multiple comparison analysis was performed with the Tukey
post hoc test.
RESULTS: μCT analysis demonstrated significant osteoporosis of the alveolar bone in the
OVX group. Exposure of these animals to HFA was able to restore the bone density to the
level of the LMD and sham group. Fluorescent and FTIR microscopy demonstrated a higher
level of bone formation in response to HFA. Similarly histology and immunohistochemistry
studies demonstrated lower levels of osteoclast activity in response to mechanical
stimulation. RNA and protein studies demonstrated upregulation of osteogenic markers.
CONCLUSION: This investigation could have an impact in the field of clinical dentistry and
on the quality of life of patients with osteoporosis. Not only will it establish a non-invasive
approach to preserve healthy bone in the jaws, but it will also offer an effective method to
recover bone density that has been lost due to osteoporosis.
OP55 CYTOKINES AS MARKERS OF OPTIMAL ORTHODONTIC FORCES
Mohammed Aljearah, Lee Yoobin, Nikhil Narkhede, Cristina Texieira, Consortium for
Translational Orthodontic Research, New York University, USA
AIMS: To investigate the expression and activity of inflammatory markers in response to
different magnitudes of orthodontic force and correlate this inflammatory response with other
molecular and cellular events during orthodontic tooth movement.
MATERIALS AND METHOD: Two hundred and forty five adult Sprague Dawley male rats
(aged 120 days) were divided into control, sham, and five different experimental groups. The
experimental groups received different magnitudes of force to the upper right maxillary first
molar using a Sentalloy coil spring. In the sham group, the spring was not activated. The
control group did not receive any appliance. At day 1, 3, 7, 14, and 28, the maxillae were
collected for microcomputed tomographic, light microscopy, protein and reverse
transcriptase polymerase chain reaction analyses. Comparisons between groups were
assessed by analysis of variance. Pairwise multiple comparison analysis was performed with
the Tukey post hoc test.
RESULTS: There was a linear relationship between the force and the level of cytokine
expression during lower magnitudes of force. Higher magnitudes of force did not increase
the expression of cytokines. Activity of CCL2, CCL5, IL-1, TNF, RANKL, and the number of
osteoclasts reached a saturation point in response to higher magnitudes of force long term,
which was accompanied by an unchanged rate of tooth movement.
CONCLUSION: After a certain magnitude of force, there is a saturation in the biological
response, where a higher magnitude of force does not increase inflammatory markers,
osteoclasts, or the amount of tooth movement. Therefore, use of higher forces to accelerate
the rate of tooth movement is not justified.
OP56 SHARED GENETIC CONTROL IN THE DEVELOPMENT OF THE PERMANENT
DENTITION IN THE MIXED DENTITION STAGE ON DENTAL PANTOMOGRAMS
Kati Kujasalo1, Paula Pesonen2, Raija Lähdesmäki1, 1Department of Oral Development and
Orthodontics, University of Oulu and 2Institute of Dentistry, University of Oulu, Finland
AIMS: To examine the prevalence of disturbances seen in tooth formation during the
second mixed dentition stage in the late developing permanent dentition (LD). Missing teeth,
displaced maxillary canines, transpositions and distoangular positioned mandibular second
premolars were examined for significance. and prevalence of each anomaly was reported to
assess the evidence for shared genetic control.
MATERIALS AND METHOD: The study approach was retrospective and cross-sectional.
Prevalence of disturbances in tooth formation was examined using panoramic radiographs of
1454 children (686 girls, 768 boys) living in Finland. The data was collected in Lapinlahti
Health Center during annual dental check-ups during 1987-2007. The purpose was to
examine the development of the permanent dentition. The mean age was 9.3 years for both
genders. The study group consisted of 108 children who expressed LD and a control group
of 1311 children with early or normal timing in the development of the permanent dentition
(END). Of the study data, 35 of the radiographs could not be counted.
RESULTS: A late developing dentition was found in 7.6 per cent of the children. Prevalence
for missing teeth was 7.6 per cent. The absence of one or more teeth was more common in
LD than in END. Excess overlapping of the crown of the permanent canine and the root of
the lateral incisor was more common in LD (16.2%) than in END (5.4%). The prevalence of
an excessively inclined canine (≥25°) was 9.6 per cent. It was more common among girls
with LD (20.5%) than in END (10.7%) in the maxilla. In the mandible the prevalence was
15.3 per cent and it was more common in LD (22.8%) than in END (14.6%) for both genders.
The prevalence for distally displaced second premolars was 6.3 per cent with an equal
distribution in the LD and END groups, being however more common in END girls and in LD
boys. Fourteen transpositions were recorded, a prevalence of 1 per cent. Only one
transposition was found in the LD group.
CONCLUSION:
Significant differences were not observed for excessively inclined
mandibular canines, transpositions or distally displaced mandibular premolars. The results
suggest that delayed tooth development, displaced maxillary canines and missing teeth have
a biological link to each other and should be considered during oral and dental check-ups.