1. health and fitness
2. disease
3. gerd and acid reflux

‫ﺑﺴﻢ اﷲ اﻟﺮﺣﻤﻦ اﻟﺮﺣﻴﻢ‬
University of Khartoum
Graduate College
Postgraduate Medical and Health studies Board
Faculty of Dentistry
Resting Tongue Position and its Relation
To the State of Dentition among patients attending dental clinic
Faculty of dentistry University of Khartoum
By:
Rasha Afifi Mohammed
B.D.S (U of K)
A thesis submitted in partial fulfillment for the requirements of the
Master Degree MSc in Prosthodontis, 2009
Supervisor:
Dr. Magdi Wadie Gilada
B.D.S (Alex.), MSc (Lond.)
I dedicate this work to my parents who inspired me
to strive for excellence and made the study of
dentistry possible.
To my husband and children for their love, support
,understanding and encouragement.
To my colleagues and students.
RASHA.
I would like to express my gratitude to Dr. Magdi Wadie, my supervisor
great teacher, for his great help.
I also thank Dr. Nadia Khalifa for generosity and unlimited support.
Special thanks to my husband Talal, my colleagues Asim Satti, Nahla
Salah.
Finally yet importantly, I thank the patients, my colleagues and my
family who endured the hard times I spent working on this research.
ABSTRACT
Many studies had been done to investigate the prevalence of
abnormal (retracted) tongue position at rest. The complexity of
construction of dentures makes this study of great interest especially to re
construction of the lower denture.
Aim: was to explore the relationship between tongue retraction and state
of dentition, and to identify potentially related parameters.
Materials and methods: The resting tongue positions were recorded in
subjects; partially edentulous in the lower jaw (n=63), compared to
dentate (n=81), and completely edentulous in the lower jaw (n=52).
Potentially related parameters, such as age, sex, tempromandibular
disorder, duration of edentulism, palatal vault and number of extracted
teeth were recorded. This cross-sectional study targeted patients and the
students attending the Prosthodontic Clinic at the Faculty of Dentistry,
University of Khartoum. The data was analyzed using SPSS. Chi-Square
test was used to assess the relation between the tongue position and the
related parameters.
Results:
the results demonstrated abnormal resting tongue position;
(94,2%), of completely edentulous subjects, and (63.5%) in the partially
edentulous, while no abnormal position observed in the dentate group.
The number of natural lower teeth correlated with the retracted tongue
position at rest in partially edentulous group. The retraction of the tongue
position was also found related to age and number of teeth in the partially
edentulous group.
Conclusion: the abnormal position of the resting tongue increased with
decreased number of natural teeth.
‫اﻟﻤﺴﺘﺨﻠﺺ‬
‫ﻟﻘﺩ ﺃﺠﺭﻴﺕ ﻋﺩﺓ ﺩﺭﺍ ﺴﺎﺕ ﺘﻭﻀﺢ ﺍﻟﻭﻀﻊ ﺍﻟﻁﺒﻴﻌﻰ ﻟﻠﻠﺴﺎﻥ ﺩﺍﺨل ﻓﻡ ﺍﻻﻨﺴﺎﻥ‬
‫ﻭﺫﻟﻙ ﻨﺴﺒﺔ ﻟﻠﺼﻌﻭﺒﺔ ﺍﻟﺘﻰ ﺘﻭﺍﺠﻪ ﻁﺒﻴﺏ ﺍﻻﺴﻨﺎﻥ ﻓﻰ ﺼﻨﻊ ﺍﻻﺴﺘﻌﺎﻀﺎﺕ ﺍﻟـﺼﻨﺎﻋﻴﺔ‬
‫ﺍﻟﻤﺘﺤﺭﻜﺔ ﻋﻠﻰ ﺍﻻﺨﺹ ﺘﺭﻜﻴﺒﺎﺕ ﺍﻟﻔﻙ ﺃﻻﺴﻔل‪.‬‬
‫ﺍﻻﻫـﺩﺍﻑ ‪:‬ﺍﻟﻬﺩﻑ ﻤﻥ ﻫﺫﺓ ﺍﻟﺩﺭﺍﺴﺔ ﻤﺤﺎﻭﻟﺔ ﺘﻭﻀﻴﺢ ﺘﻐﻴﺭﻭﻀﻊ ﺍﻟﻠـﺴﺎﻥ ﻟﻤﻭﻀـﻌﻪ‬
‫ﺍﻟﻁﺒﻴﻌﻰ ﻜﻨﺘﻴﺠﺔ ﻟﻔﻘﺩﺍﻥ ﺍﻻﺴﻨﺎﻥ ﻭﻤﻌﺭﻓﺔ ﺒﻘﻴﺔ ﺍﻟﻌﻭﺍﻤل ﺍﻟﺘﻰ ﺘﺅﺜﺭ ﻋﻠﻰ ﻫﺫﺍ ﺍﻟﺘﻐﻴﺭ‪.‬‬
‫ﻤﻨﻬﺠﻴﺔ ﺍﻟﺒﺤﺙ‪ :‬ﺘﻡ ﺘﺴﺠﻴل ﻭﻀﻊ ﺍﻟﻠﺴﺎﻥ ﺍﻟﻁﺒﻴﻌﻰ )ﻓﻰ ﺤﺎﻟﺔ ﺴﻜﻭﻥ( ﻓـﻰ ﻋـﺩﺩ‪63‬‬
‫)ﺜﻼﺜﺔ ﻭﺴﺘﻭﻥ( ﻤﻥ ﺍﻟﻤﺭﻀﻰ ﺍﻟﺫﻴﻥ ﻓﻘﺩﻭﺍ ﻋﺩﺩ ﻤﻥ ﺍﺴﻨﺎﻨﻬﻡ ﻓﻰ ﺍﻟﻔﻙ ﺍﻻﺴـﻔل ﻭﺘـﻡ‬
‫ﻀﺎ ﻗﺩ ﻓﻘﺩﻭﺍ ﺃﺴﻨﺎﻨﻬﻡ ﻜﻠﻴﹰﺎ ﻓﻰ ﺍﻟﻔـﻙ ﺍﻻﺴـﻔل‬
‫ﻤﻘﺎﺭﻨﺘﻬﻡ ﻤﻊ ‪)52‬ﺍﺜﻨﺎﻥ ﻭﺨﻤﺴﻭﻥ( ﻤﺭﻴ ‪‬‬
‫ﻭﻭﺍﺤﺩ ﻭﺜﻤﺎﻨﻭﻥ ﻁﺎﻟﺒﹰﺎ ﻋﺩﺩ ﺍﺴﻨﺎﻨﻬﻡ ﻤﻜﺘﻤﻠﺔ ﻓﻰ ﺍﻟﻔﻙ ﺍﻻﺴﻔل ﻜﻤﺎ ﺘﻡ ﺘﺴﺠﻴل ﺍﻟﻌﻭﺍﻤـل‬
‫ﺍﻻﺨﺭﻯ ﺃﻟﺘﻰ ﻴﻌﺘﻘﺩ ﺃﻥ ﻟﻬﺎ ﺘﺄﺜﻴﺭﹰﺍ ﻓﻰ ﺘﻐﻴﺭ ﻭﻀـﻊ ﺍﻟﻠـﺴﺎﻥ ﻤﺜـل )ﺍﻟﻌﻤﺭ‪،‬ﺍﻟﻨـﻭﻉ‪،‬‬
‫ﺍﻁﺭﺍﺒﺎﺕ ﺍﻟﻔﻙ ﺍﻟﺼﺩﻏﻰ‪ ،‬ﺸﻜل ﺴﻘﻑ ﺍﻟﺤﻠﻕ ‪،‬ﻤﺩﺓ ﺨﻠﻊ ﺍﻻﺴـﻨﺎﻥ ﻭﻋـﺩﺩ ﺍﻻﺴـﻨﺎﻥ‬
‫ﺍﻟﻤﺨﻠﻭﻋﺔ( ﻭﺘﻡ ﺤﺼﺭ ﺍﻟﺤﺎﻻﺕ ﺍﻟﺘﻰ ﺍﺠﺭﻴﺕ ﻋﻠﻴﻬﺎ ﺍﻟﺩﺭﺍﺴﺔ ﻤﻥ ﺍﻟﻤﺭﻀﻰ ﺍﻟﻤﺘﺭﺩﺩﻴﻥ‬
‫ﻋﻠﻰ ﻤﺠﻤﻊ ﻋﻴﺎﺩﺍﺕ ﺍﻻﺴﺘﻌﺎﻀﺔ ﺍﻟﺼﻨﺎﻋﻴﺔ ﺒﻜﻠﻴﺔ ﻁﺏ ﺍﻻﺴﻨﺎﻥ ﺒﺠﺎﻤﻌـﺔ ﺍﻟﺨﺭﻁـﻭﻡ‬
‫ﻭﻁﻼﺏ ﺍﻟﻔﺼﻠﻴﻥ ﺍﻟﺭﺍﺒﻊ ﻭﺍﻟﺨﺎﻤﺱ ﺒﻜﻠﻴﺔ ﻁﺏ ﺍﻻﺴﻨﺎﻥ ﺠﺎﻤﻌﺔ ﺍﻟﺨﺭﻁﻭﻡ‪.‬‬
‫ﺍﺠﺭﻯ ﺘﺤﻠﻴل ﻟﻠﺒﻴﺎﻨﺎﺕ ﺒﻭﺍﺴﻁﺔ ﺒﺭﻨﺎﻤﺞ )‪ ( SPSS‬ﻭﺒﺎﺴﺘﺨﺩﺍﻡ ﺍﺨﺘﺒـﺎﺭ ‪Chi-Square‬‬
‫ﺘﻡ ﺒﺤﺙ ﺍﻟﻌﻼﻗﺔ ﺒﻴﻥ ﺘﻐﻴﺭ ﻭﻀﻊ ﺍﻟﻠﺴﺎﻥ ﺩﺍﺨل ﺍﻟﻔﻡ ﻭﺍﻟﻌﻭﺍﻤل ﺍﻟﻤﺅﺜﺭﺓ ﻓﻰ ﺫﻟﻙ ‪.‬‬
‫ﺍﻟﻨﺘﺎﺌﺞ‪ :‬ﺃﻓﺭﺯﺕ ﺍﻟﻨﺘﺄﺌﺞ ﺃﻥ ﺍﻟﻭﻀﻊ ﺍﻟﻐﻴﺭ ﻁﺒﻴﻌﻰ ﻟﻠﻠﺴﺎﻥ ﻭﺠﺩ ﺒﻨـﺴﺒﺔ ‪ %94.2‬ﻓـﻰ‬
‫ﺍﻟﻤﺭﻀﻲ ﺍﻟﺫﻴﻥ ﻓﻘﺩﻭﺍ ﺍﺴﻨﺎﻨﻬﻡ ﻜﻠﻴﹰﺎ ﻓﻰ ﺍﻟﻔﻙ ﺍﻻﺴﻔل ﻭﺒﻨﺴﺒﺔ ‪ % 63.5‬ﻤﻥ ﺍﻟﻤﺭﻀـﻰ‬
‫ﺍﻟﺫﻴﻥ ﻓﻘﺩﻭ ﺍﺴﻨﺎﻨﻬﻡ ﺠﺯﺌﻴﹰﺎ ﺒﻴﻨﻤﺎ ﻟﻡ ﻴﻭﺠﺩ ﺃﻯ ﺘﻐﻴﻴﺭ ﻓﻰ ﻭﻀﻊ ﺍﻟﻠﺴﺎﻥ ﻋﻨـﺩ ﺍﻟﻁﻠﺒـﺔ‬
‫ﺍﻟﺫﻴﻥ ﻋﺩﺩ ﺃﺴﻨﺎﻨﻬﻡ ﻤﻜﺘﻤل ‪ ،‬ﺃﻥ ﻋﺩﺩ ﺍﻻﺴﻨﺎﻥ ﻓﻰ ﺍﻟﻔﻙ ﺍﻻﺴﻔل ﻭﻋﻤﺭ ﺍﻟﺸﺨﺹ ﻟـﻪ‬
‫ﻋﻼﻗﺔ ﺒﻭﻀﻊ ﺍﻟﻠﺴﺎﻥ ﺍﻟﻁﺒﻴﻌﻰ ﻋﻨﺩ ﺍﻟﻤﺭﻀﻰ ﺍﻟﺫﻴﻥ ﻓﻘﺩﻭﺍ ﺍﺴﻨﺎﻨﻬﻡ ﺠﺯﺌﻴﹰﺎ‪.‬‬
‫ﺍﻟﺨﻼﺼﺔ‪ :‬ﻤﻥ ﻫﺫﻩ ﺍﻟﺩﺭﺍﺴﺔ ﻴﻤﻜﻥ ﺃﻥ ﻨﺴﺘﻨﺘﺞ ﺃﻥ ﻭﻀﻊ ﺍﻟﻠﺴﺎﻥ ﻴﺘﺄﺜﺭ ﺒﻌﺩﺩ ﺍﻻﺴـﻨﺎﻥ‬
‫ﺍﻟﻤﻭﺠﻭﺩﺓ ﻓﻰ ﺍﻟﻔﻙ ﺍﻻﺴﻔل ‪.‬‬
LIST OF TABLES
Table
Page
Table 1: Patients groups depending on the dental status
24
Table 2: Distribution of resting tongue position according to type of dentition
25
Table 3: Age Distribution according to type of dentition
27
Table 4:Age Distribution in different sex groups
27
Table 5: Resting tongue position distribution in gender
28
Table 6: Resting tongue position distribution in Age
28
Table 7: TMD distribution according to type of dentition
29
Table 8: Resting tongue position distribution in participants with & without
29
TMD
Table 9: The palate vault distribution
31
Table 10: Resting tongue position distribution in different types of palate vault
31
Table 11: Duration of edentulism
33
Table12: Existing denture in the edentulous groups
33
Table 13: Association between Resting tongue position & duration of
34
edentoulism
Table 14: Association between Resting tongue position & Existence of denture
34
Table 15:Kennedy's classification among partially edentulous participants
36
Table 16: Association between Resting tongue position & Kennedy's
36
classification among partially edentulous participants
Table 17: Number of extracted Teeth among partially edentulous
38
Table 18: Number of extracted teeth
38
Table 19: Association between Resting tongue position & Mean number of
38
extracted teeth in partially edentulous participants
Table 20: Angle's classification among dentate participants
39
Table21: Resting tongue position distribution in participants with & without
39
TMD
Table 22: Resting tongue position distribution in different types of palate vault
40
Table 23:Association between Resting tongue position & duration of
40
edentoulism
Table 24:Association between Resting tongue position & Existence of denture
41
Table 25:Association between Resting tongue position & Kennedy's
41
classification among partially edentulous participants
Table 26 :Association between resting tongue position & Angle's classification
in Dentate participants
42
LIST OF FIGURES
Figure
Page
Fig. 1: Distribution of resting tongue position according to type of dentition
25
Fig. 2 Gender distribution
26
Fig 3: resting tongue position distribution in participant with and without TMD
29
Fig 4: resting tongue position distribution in different types of palate vault
32
Fig.5: association between resting tongue position and duration of edentulism
35
Fig 6: association between resting tongue position and existence of denture
35
Fig.7: Association between Resting tongue position & Kennedy's
37
classification among partially edentulous participants
CONTENTS
DEDICATION…………………………………………..I
ACKNOWLEDGMENT………………………………………...II
ENGLISH ABSTRACT…………………………………….......III
ARABIC ABSTRACT…………………………………………...V
LIST OF TABLES ……………………………………………..VII
LIST OF FIGURE ……………………………………………...IX
CHAPTER ONE
INTRODUCTION AND LITERATURE REVIEW………… 1-18
CHABTER TWO
MATERIAL AND METHODS…………………………..… 19-23
CHABTER THREE
RESULTS…………………………………………………
24-42
CHABTER FUOR
DISCSSION…………………………………………………. 43-47
CONCLUSION…………………………………………………..48
RECOMMENDATION…………….……………………………49
REFERENCES……………………………………………. 50-62
APPENDICES……………………………………………. . 63-67
Chapter One
INTRODUCTION
&
LITERATURE
REVIEW
1- Introduction and literature review
The prosthetic rehabilitation of the edentulous lower jaw often
becomes complicated by the presence of an unfavourable resting tongue
position
(1-4)
. The tongue is a very active and extremely sensitive organ,
performing on a complex muscle background. Anatomically, intrinsic and
extrinsic muscle groups compose the tongue. The intrinsic muscle group
comprises the genioglossal, hyoglossal and styloglossal muscles, while
the extrinsic muscle group comprises the longitudinal, transversal and
vertical lingual muscles (5) .
1.1 Function of the tongue:
Basic functions of the stomatognathic system such as mastication,
deglutition and speech, require the active involvement of the tongue in
order to be carried out (6, 1, 7, 8) .The tongue itself is an adept tool, housing
taste
buds,
mechanoreceptors,
thermoreceptors,
nociceptors
and
proprioceptors on its surface. Therefore, during comminution, the tongue
plays an important role in the transmission of sensorial information
detected by the receptors to the brainstem, which may cause the
modification of oral physiological movements
(9-12)
. The characteristics
which dictate the functional performance of the tongue are its size,
strength, state of health, movement patterns and resting position of the
tongue (7, 13) .
1.1.1.Muscles of the tongue:
1.1.1.1. Genioglossus Muscle (GG):
Tongue function is closely related to GG muscle. The genioglossus
(GG) muscle is known to be the tongue protractor. It arises from the
mental tubercles on the inner surface of the chin, and most of the fibres
spread fanwise in the tongue. The fibres of the GG muscle diverge from
their origin; the most anterior fibres curve upward and anteriorly into the
tip of the tongue, whereas the posterior fibres reach the base of the tongue
in an almost horizontal course and the most inferior bundles are attached
to the body of the hyoid bone (14) .Therefore, contraction and relaxationof
the GG muscle is closely related to various oral functions such as
mastication and deglutition. Several animal experiments have been
carried out to explain the coordination between tongue movement and
rhythmic jaw movement
(15-20)
. However, there have been few
experiments in humans on GG muscle activity during rhythmic jaw
movements.
There was study conducted to examine the pattern of human GG
muscle activity during rhythmic open–close jaw movement, their findings
that the EMG activities of GG, Masseter and Digastric muscles in man
are under the control of closely related central neural mechanisms (21) .
1.1.1.2. Hyoglossus muscle:
It originates from the body and greater cornu of hyoid bone, and it
blends with other muscles of the tongue. It depresses tongue.
1.1.1. 3 Styloglossus muscle:
It originates from styloid process of temporal bone ,and blends
with other muscles of tongue. It draws tongue upward and backward.
1.1.1. 4.Platoglossus muscle:
It originates from palatine aponeurosis, and inserts on sides of
tongue. It pulls roots of tongue upward and backward, narrows
oropharyngeal isthmus.
1.1.1. 5.Intrinsic muscles:
Are confined to the tongue and are not attached to bone .They alter
the shape of the tongue.
1.1.2 Coordination between Tongue- Jaw Movements:
There have been suggestions that the EMG activities of the GG,
Masseter and Digastric muscles in man are under the control of closely
related central neural mechanisms
(22)
. Hiyama et al
(23)
reported that
genioglossus EMG activity was closely linked to that of the masticatory
muscle during jaw-tapping movement, suggesting that there may be a link
between the mutual central pattern generators for the tongue and
masticatory muscles in the central nervous system..
Ishiwata et al (24,25), demonstrated that group II afferents that originated
from muscle spindles in the temporalis muscle in both animals
humans
(25)
(24)
and
were mainly responsible for the reflexive fluctuation in the
membrane potentials of hypoglossal motoneurons. They concluded that
tongue position was reflexively controlled by jaw position.
Unfortunately, there has been no report on whether the jaw position
is reflexively controlled by tongue position. It seems likely that
cooperative activity between the tongue and masticatory muscles is
controlled not only by the jaw-tongue reflex
(24, 25).
Or an integrative
central pattern generator, but also by a reflexive pathway through which
jaw position is controlled by tongue position, perhaps by way of afferents
from the extrinsic tongue muscle (eg, muscle spindles)
(26)
. They used
feedback of EMG activity of Masseter and anterior temporalis muscles to
carefully determine the tongue position and to confirm a change in tongue
position, especially when the tongue was in the anterior position, with the
activation of both intrinsic and extrinsic tongue muscles. No significant
increase in masseter EMG activity when the tongue was in the superior
position was found, whereas the EMG activity of the anterior temporalis
muscle showed a significant increase when the tongue was in that
position. The reason for this behavioral discrepancy between the masseter
and anterior temporalis muscles is unknown, but the effect of superior
positioning of the tongue may be different for the two jaw-closing
muscles (27).
1.1.3 The role of tongue in breathing:
Upper airway regulation is involved in breathing through the mouth
and the ability to speak. In this regulation the genioglossal muscle is
active in the inspiratory phase
(28-
30).
The tonic activity of the
genioglossus prevents tongue relapse with occlusion of the airways
(28-31).
Thus, it is seen during quiet sleep (32). Also breathing with the jaws closed
or slightly opened
(17, 33)
. It increased when the head is tilted from the
upright to the supine position
(34).
Roberts (35) noted that the genioglossus
muscle contributes to maintaining pharyngeal airway patency in
micrognathic infants.
In
addition,
the
upper
airway
may
be
controlled
by
chemoreceptors, pulmonary mechanoreceptors or non-specific respiratory
stimuli that changes in genioglossus activity are proportional to changes
in diaphragm activity at any level of increased chemical drive
(36)
.
Moreover, upper airway impairment may involve respiratory muscle
function, rather than abnormal upper airway muscle control
(37, 38) .
In
pervious study, there was indication that the presence of a reflex pathway
that regulates genioglossus muscle activity in response to upper airway
pressure loads, indicating involvement of medullary respiratory
centres(39).
Genioglossus activity is not affected by paralyzation of the
oropharyngeal mucosa
(40).
However, increasing the anaesthetic level had
a large depressant action on the hypoglossal nerve (41). Stimuli of negative
airway pressure caused reflex activation of the genioglossus muscle in
awake human subjects
(42).
In addition, reflexes were mediated by
supraglottic and subglottic airway receptors
(43)
. Thus,the genioglossus
muscle is the main protruder of the tongue, and acts as an accessory
respiratory muscle, resulting in advancement of the base of the tongue
and dilation of the upper airway(44).
1.1.4 The role of the tongue in swallowing:
In swallowing, the tongue is essential in controlling the flow of a
bolus and fragments, within the oral cavity. Abd el Malek etl
(45)
photographed the tongue movements of subjects during the consumption
of a series of food products. The tongue performed specific movements
defined as; preparation, throwing, guarding, selection and bolus
formation over the eating sequence. Recently, more advanced techniques
have been employed to provide more detail .The tongue plays important
roles in swallowing, especially in the transport of bolus of food from the
anterior oral cavity to the pharynx
(46-48)
. Previous studies using
videofluorography,
electropalatography
and
ultrasound
techniques
revealed that the anterior tongue (AT) folds the bolus posterior transport
of the resulting bolus and its final deposition into the oro-pharynx
(49-55).
The tongue is vital for the transport and positioning of food between the
molars, selecting pharynx and presses it to the hard palate not to the teeth
to propel it into the fragments for further comminution, incorporation of
saliva with fragments, (10, 56, and 57).
1.1.5 The role of the tongue in speech:
On
speech
a
very
complex
and
imperfectly
under
stood
neurophysiological mechanism governs the production of speech. A large
number of oral mechanosensitive recepters (tactile and kinesthetic) are
involved in its motor control. The tongue has a critical impact on speech
production and needs optimal mobility to lift, protrude, flatten, form a
groove(s), and contact adjacent tissues freely. Jaw and tooth relationships
enable the tongue to articulate against the maxillary teeth or alveolus
permit the maxillary teeth and lower lip to make easy contact, and allow
the lips to touch.
1.2 The size of the tongue:
The size of the tongue also affects its function if it is of adequate
size , normally, on slight mouth opening, the tongue rests on the floor of
the mouth, to the inside or on the top of the ridges, filling the mouth
cavity and presenting a fluid-like appearance or it is slightly overfills the
floor of the mouth. Excessively large tongue occurs when all teeth have
been absent for an extended period, resulting in the increase of the space
available to the tongue, allowing for abnormal development of the size of
the tongue (2) .
1.3-Position of the tongue:
In the resting mandibular position, the tongue is assumed to touch
the lingual surfaces of the teeth as if the tongue counteracted the pressure
from buccal soft tissues such as cheek and lip
(58)
. From an orthodontic
point of view, this principle (known as the ‘equilibrium theory’) is
applied to both upper and lower teeth and is important in light of
orthodontic relapse during the retention period
(58)
. Normal tongue
position at rest has been clinically recognized as the posture, which
achieves the equilibrium mentioned earlier (58, 59) .
The tongue position is also reported to be changeable with the use
of cribs (60) ,and after orthognathic surgery (61) . Nevertheless, in searching
of the literature, no well-accepted objective definitions as to the tongue
position in the field of orthodontics were found. On the contrary, a variety
of approaches to tongue position evaluation have been introduced in the
prosthodontic field, most of which have been developed and focused on
the relationship between tongue position and the stability of the
removable lower denture (62- 64) .
Although the authors in some reports were successful in clearly
classifying the normal and abnormal tongue position visually with a
voluntary open mouth
(62 -64)
. Apart from inter/ intra observer difference
of visual evaluation, they question whether being dentate or partially
dentate could affect the tongue position at rest as Kotsiomiti and Kapari
suggested
(62)
. Moreover, voluntary jaw opening itself would change the
tongue position in relation to the maxillary dentition because of the jawtongue reflex in humans
(65)
. Simple method using a pressure sensor
evaluated the tongue position change associated with a head position
alteration (66) .
1.3.1 The normal rest position of the tongue:
The resting position is important during growth of the oral structures
(1)
, and for speech articulation (3, 6, and 67) .
The term ‘tongue resting position’ was used by Cookson
(68)
,
and
referred to ‘the reproducible physiologically relaxed position of the
organ, observed when the lips are parted and the mandible is slightly
opened from rest, this term does not involve any functional parameter.
Although it can be debated whether the observed position actually
represents the most relaxed state of the complex tongue musculature, the
procedure was employed because it was practical, convenient and
produced a highly reproducible outcome.
Wright (64, 68) , was the first to publish on the tongue position and its
relation to denture stability. He introduced the term ‘normal position’ of
the tongue, in contrast to the ‘abnormal’one, by defining normal position
as ‘the optimum position from which it can most easily start and most
effectively perform its functions’. He advised with other authers that the
tongue resting position must be observed, while the patient is unaware of
what the dentist is examining (67, 1, and 2) .
1.3.2 The abnormal position of the tongue:
Wright (64, 68), in his extensive publications on the subject, confidently
reports that the abnormal position is closely related to abnormal function.
This opinion is shared by Beresin ,
Sciesser
(1)
and Lang
(4)
, who
reported that ‘the retraction accompanied eating, talking, yawning and
other functional and non-functional movements of the lower jaw’ .
Wright classification of tongue positions is generally adopted, and
only minor alterations concerning the distinguishing criteria (criteria of
measuring the abnormal position of tongue), and definitions, have been
introduced. When the tongue appears withdrawn to the back of the oral
cavity, adapting a square or triangular shape and the anterior part of the
floor is exposed, it has been termed as ‘abnormal’. The term ‘abnormal’
tongue position, is also found as ‘awkward’
(67, 1)
, or ‘retracted’ in
reference to the tongue appearance (69, 67, 7, 70, 13, 3) .
It has been referred that, the habit of abnormal positioning of the
tongue does not exist at birth and develops with age in response to the
alteration of the anatomic and/or functional oral conditions
(71, 67, and 72)
.
Malpositioned or missing teeth, dentures and malformations were present
in cases of abnormal position.
The prevalence of the abnormal tongue resting position has been
closed to be either 35% estimated probably on a random population
sample (69, 2, 13, 73, 8) , or 25% (1, 7, 70, 74).
The loss of natural teeth is expected to introduce occlusal
disharmony, changes and final loss of the occlusal scheme. Such a
gradually developed dysfunction of the stomatognathic system could be
accompanied by changes of the tongue resting position and functional
movements. From this aspect, the orthodontic anomalies of the dentate
would have to be examined for their correlation to the habit.
The loss of natural teeth also results in the increase of the space
available to the tongue
(2)
. Therefore, the mechanism of the habit
development could be searched for in relation to the space offered. It has
been indeed reported that the upper or lower normal position is
influenced by the palatal vault. When some of the natural teeth are
missing, the tongue fills their space and becomes seemingly enlarged (71) .
During function, the chewing and swallowing procedures may again need
to alter, because of the apparent volume change. In a pilot study
(75)
, the
principal findings , however, that the incidence of the abnormal positions
increases gradually through the transition from the dentate state to the
partially edentulous and finally completely edentulous.
Progressing age induces changes of oral anatomy, such as inferior
movement of the hyoid bone and reduction of pharyngeal airway space
and increase of the tongue volume (76- 78) . Partial loss of teeth, apart from
disrupting intraoral morphology, results in increased mandibular jaw
angle
(79)
. The anatomical changes may be linked to the establishment of
an abnormal resting tongue through their main consequences, namely,
modified function of oral musculature and alterations of the space
available for the tongue.
The effects of mouth breathing habit include; alterations of muscles,
functions, posture, bone and behavior
(80, 81)
. Considering the alterations
mentioned above, the integration of otorhinolaryngology, orthodontic and
speech language pathology is necessary (82,
83)
. Ricketts
(84)
stated that
dental eruption is guided by the form and position of basal bone, which is
shaped by the muscular organs, i.e. tongue and lips.
Furthermore, it has been emphasized that a patient with TMJ
dysfunction should avoid lifting the tongue against the palate because it
may lead to pain in the masticatory muscle or TMJ region (85, 86) . Some
investigators have noted that an abnormal tongue position at rest (ie,
static) and during function (ie, dynamic) can cause certain types of
malocclusion including anterior open bite
(87).
Proffit
(85)
, has stated that
the resting pressure of the tongue is one of the primary factors in the
maintenance of dental equilibrium. In addition, an augmented
electromyographic (EMG) activity in the tongue-protruding muscle (ie,
genioglossus muscle) has been reported in subjects with anterior open
bite
(88).
Moreover, it has been suggested that the resting tongue position
in subjects with skeletal open bites appears to be related to the position of
the incisors (89) .
Tongue position during dynamic movement is also of clinical
significance. While swallowing, the tongue is positioned anteriorly in
subjects with anterior open bite (90) .This triggers changes in dentofacial
morphology, including the proclination of incisors, overeruption of
molars, and increased facial height
(91)
. Recently, it has been
demonstrated that tongue pressure is gradually distributed on the palatal
surface during swallowing in adult subjects with normal oral function and
occlusion, ie, weaker pressure is exerted anteriorly, whereas stronger
pressure is exerted posteriorly (92) .
In subjects with obstructive sleep apnea (OSA), in which the tongue
plays a crucial role, there are several significant correlations between
craniofacial and tongue variables. Furthermore, an inferior position of the
tongue was associated with the severity of OSA, which causes a fan-like
configuration of the lower part of the face in the sagittal plane. Thus, the
static position of the tongue appears to affect both occlusion and
craniofacial morphology.
In addition, the tongue resting position is a critical feature,
regarding the complete denture function. With the lower denture in place,
it is essential that the tongue is comfortably filling the mouth cavity and
is in contact with the lingual flange, sealing the denture border.
Where the tongue is found is in a different position than this, a good
border seal may be difficult to obtain (7, 2, 72, and 75) . Levin, and Renner(73,
13)
, suggested that the abnormal tongue position develops as a reflex,
serving for specific purposes and relating to certain functional or even
parafunctional, patterns .The development of reflexes, as the tongue is
functioning, helps complete denture wearers to stabilize their dentures. A
good example is the stabilizing role that the tongue plays during
swallowing, as it presses the posterior part of the upper denture in place
(93, 8)
. Where the denture is ill-fitting, badly constructed, or occluding
with natural anterior, the tongue is called to compensate the lack of
stability; this may result in modified function, development of habits, or
alteration of reflexes
(74, 6, and 13)
. The abnormal tongue resting position
could be indicative of such a differentiation of the muscular activity.
There is no doubt that the construction of a complete denture
becomes more complicated in case the patient tends to withdraw the
tongue on opening. The anterior lingual sulcus is distorted – elevated and
widened (2, 72, 75). The muscles of the floor of the mouth appear tensed (1, 7,
and 76).
Therefore, the flange width and extension is difficult to estimate,
and peripheral sealing is often inevitable.
Furthermore, as the tongue retracts, its base becomes broader and
contacts the lower posterior teeth, constantly unseating the denture base
(1,7)
.
The significance of the tongue position is easily demonstrated in such
cases by instructing the patient to place the tongue in a normal position,
in which case the retention is instantly improved
(8)
. Following the
delivery of the denture, it is expected that a considerable amount of the
lower base retention will be lost every time the patient slightly opens their
mouth. Beyond mere slight opening, oral functions such as speech,
deglutition and chewing involve complex and finely coordinated
movements of intra-oral musculature
(6, 8)
. The question arises, in which
extend an observed abnormal resting tongue would interfere with them.
Although the adaptation to complete dentures is facilitated by good
denture retention
(94),
and good oral motor ability
(95)
, the overall
satisfaction with dentures involves several diverse factors, apart from
lower denture retention, and the contribution of each factor remains an
unresolved issue of prosthodontic research
(96-,98)
. According to most
clinical textbooks a retracted tongue represents a considerable drawback
in constructing a functional denture and training exercises are
recommended(2,76,
13, 7, 8)
. On studying the relationship between tongue
and stability of complete mandibular denturethe anatomic morphology
and functional movement of tongue play an important role in the stability
of the mandibular complete denture (97) .
Hypothesis:
There is relationship between tongue position and state of
dentition (partially or complete dentate), and artificial dentition, if the
number of the teeth decreased there will be increasing in the abnormal
position of the tongue.
Null hypotheses:
No relationship between tongue position and state of dentition,
and artificial dentition and so no relationship between abnormal position
of the tongue and decreased number of teeth.
JUSTIFICATION
It is important to investigate the tongue position in a due to its role
in constructing efficient dentures.
OBJECTIVES
General
The aim of the study is to explore the relationship between tongue
position and state of dentition and to identify potentially related
parameters.
Specific
1- 1- Underline the need for a clinical investigation directly relating the
resting tongue position.
2- The effect of abnormal tongue position on denture construction.
3- assessing the functional and anatomical changes of oral environment
resulting from the loss of natural teeth.
Chapter Two
MATERIALS
&
METHODS
2- MATERIALS AND METHODS
2.1 Study area:
The sample would be collected from patients and students who
present at the Prosthodontic Clinic at the Faculty of Dentistry, University
of Khartoum.
2.2 Study design:
This was a cross – sectional study based on a clinical examination.
A pilot study was carried out to help establish ways of recording tongue
position and help in dividing the number of patients that will be needed in
main study. Patients were divided in three groups: edentulous in the lower
arch, partially edentulous and dentate subjects. All selected patients were
systemically healthy and from different socioeconomic groups. The
partially dentate and edentulous patients were from the clinic of
Removable Prosthodontics of Faculty of Dentistry at university of
Khartoum, and the dentate subjects were undergraduate students were
from the same faculty.
2.3 Sample Size (N);
The appropriate sample size was defined by this formula:
N
=
z².p.q
d²
z = standard normal distribution = 1.96
p= prevalence = 0.5
q= 1-p = 0.5
d= error of c. interval= 0.07
n=196
2.4 Data collection:
Clinical examination was carried out and its results recorded on an
examination sheet for each participant, which included the name, sex, and
age. Two independent investigators examined each case and the
agreement between them was 98%.
2.4.1. Extraoral examination:
2.4.1. 1.TMJ:
A simple functional examination provided information about signs
of temporomandibular disorders. The presence of at least one sign (joint
sounds, muscle/ joint palpation tenderness, pain, limitation of jaw
movement), was considered as indicative of some degree of disorder.
2.4.2. Intraoral examination:
2.4.2.1. state of the dentition:
For the edentulous, the date of recent extractions, mucosal health,
and for the partially dentate the nature of upper teeth and occlusal
relationship, was noted. For the dentate subjects the Angle's classification
and occlusal relationship were recorded.
2.4.2. 2.The vault of the palate:
In all cases, the vault of the palate, which was related to the
normal tongue appearance, was also assessed, and was characterized as
high, normal or low, in respect to the frontal cross section of the maxilla
at the upper first molar area.
2.4.2. 3. Position of tongue:
During the present study, the tongue resting position was recorded
at the beginning of the examination, and checked at the end of it, after the
patient had opened the mouth a number of times and felt somewhat more
relaxed. In the case of non-agreement, the subject was examined in
another session. For each examination, the subject was instructed to
calmly and slowly open the mouth to such an extent that the examiner can
see the tongue position. In the case where the tongue appeared abnormal,
the patient was instructed to close, swallow and open again. The whole
organ must appeared relaxed and free of muscular contractions by the
time the recording was performed.
2.5. Criteria of selection:
The tongue position was categorized by:
(i) The extent by which the floor was visible.
(ii) The lateral borders, in relation to the lingual surfaces of the teeth, or
lingual side of the ridge.
(iii) The apex, in relation to the lingual surfaces of the teeth or lingual
anterior side of the ridge.
Using the above criteria the tongue resting position
was grouped as follows:
1. Normal upper: floor not visible; lateral borders over the occlusal
surfaces, or on the ridge; apex behind or over the lingual surfaces of
anteriors, or on the ridge
2. Normal lower: floor not visible; lateral borders next to lingual
surfaces, or inside the ridge; apex behind the lingual surfaces of anteriors,
or behind the ridge anteriorly
3. Abnormal upper: floor visible; lateral borders over the occlusal
surfaces, or behind the end of the ridge; apex withdrawn into the body
4. Abnormal lower: floor visible; lateral borders behind the posterior
teeth, or next to the end of the ridge; apex pointing (lowered) to the floor
of the mouth. The above grouping of the tongue resting positions based
on the categories found in most publications. In general, the abnormal
tongue position was easily recognized and extremely reproducible. The
distinction between abnormal upper and abnormal lower position, was
facilitated by the appearance of the floor, which seemed to acquire in
some cases an upper and in others a lower position (1, 7, 71.72).
Exclusion criteria:
1. Patients with oral pain.
2. Mucosal lesions.
3. Surgical intervention.
4. Muscular abnormality.
5. Oral and neck tumor.
Examination canditions:
The clinical examination was carried out under well lit conditions
(dental chair light) using a standard mouth mirror.
Chapter Three
RESULTS
3-RESULTS
In this study the total sample consisted of 196 individuals of whom
(63) were partially dentate, patients were examined, (52) were edentulous
patients in the lower jaw, and (81) were dentate students (Table1).
Patients and students were recruited from the dental clinic of the
University Of Khartoum Faculty Of Dentistry. The patients and the
students were consented and the nature of clinical examination was fully
explained to the participants.
Table 1: patients groups depending on the dental status
Patient group
Frequency
percent
Edentulous lower jaw
52
26.5%
partially dentate patients
63
32.2%
dentate
81
41.3%
total
196
100%
patients
.
3.1 Resting tongue position distribution according to dental status
The majority of the edentulous participants showed abnormal
tongue position at rest (94.2%). In the partially dentste group the
abnormal tongue position was found in (63.5%). Where as none of the
dentate subjects, had an abnormal tongue position at rest (Table 2).fig.1.
Table 2: Distribution of resting tongue position according to type of
dentition:
Edentulous lower jaw
Partially dentate
Dentate
Total
Normal
Abnormal
Total
3
49
52
(5.8%)
(94.2%)
(100%)
23
40
63
(36.5%)
(63.5%)
(100%)
81
0
81
(100%)
(0%)
(100%)
107
89
196
(54.5%)
(45.4%)
(100%)
Fig. 1: Distribution of resting tongue position according to type of
dentition:
120
100
80
63.5%
Abnormal
60
94.2%
100%
40
20
0
36.5%
5.8%
Edentulous
Partially dentate
Dentate
Normal
3.2. Gender and Age distribution:
55.6% of the edentulous subjects were males and, 44.4%were
females. The mean age of the edentulous subjects was 65.25years (range
22-92yrs). In partially dentate subjects, two third were females (42,
66.7%) and 21 were males (33.3%).
The mean age was 53.48 in range (20-76). Among dentate subjects,
36 were males (44.4%) and 45 were females (55.6%). The mean age of
males was 22.67 (range 20 -31), and females was 21. 82 (range 19-24),
(Table 4).
Fig. 2 Gender distribution
66.7%
70
59.6%
55.6%
60
50
44.4%
40.4%
33.3%
40
Male
30
Female
20
10
0
Edentulous
Partially
dentate
Dentate
Table 3: Age Distribution according to type of dentition:
Mean
Std.
Deviation
Minimum
Maximum
Edentulous
65.25
11.01
22
92
Partially dentate
Dentate
53.48
22.2
14.97
1.81
20
19
76
31
Table 4:Age Distribution in different sex groups:
Age
Male
Edentulous
Partially dentate
Dentate
Mean
64.1
53.76
22.67
Female
Edentulous
Partially dentate
Dentate
66.95
53.33
21.82
Std.
Deviation
9.06
16.85
2.34
Minimu
m
50
22
20
Maximum
88
76
31
13.46
14.14
1.13
22
20
19
92
75
24
There was no significant relationship between gender and tongue
position in the three groups.
The significant relationship was observed between age and
resting tongue position in the partially dentate group (P value 0.001).
(Table 6).
Table 5: Resting tongue position distribution in gender:
Edentulous
male
female
Partially dentate
male
female
Dentate
male
female
Normal
1
(3.2%)
2
(9.5%)
Abnormal
30
(96.8%)
19
(90.5%)
Total
31
(100%)
21
(100%)
5
(23.8%)
18
(42.9%)
16
(76.2%)
24
(57.1%)
21
(100%)
42
(100%)
36
(100%)
45
(100%)
0
(0%)
0
(0%)
36
(100%)
45
(100%)
P value
Sig
0.558
Not significant
0.229
Not significant
-
-
*Chi square Test Preformed
Table 6: Resting tongue position distribution in Age:
Edentulous
Partially dentate
Dentate
N
Mean
Std. Deviation
P value
Sig
normal
3
56.7
5.8
0.167
Not significant
abnormal
49
65.8
11.1
normal
23
45.6
13.7
0.001
significant
abnormal
40
58
13.9
normal
81
22.2
1.8
abnormal 0
*Independent samples T test preformed
3.3: Tempromandibular dysfunction(TMD) distribution:
TMD occurred in 19.2% in the completely edentulous subjects,
12.7% in the partially dentate (12.7%), and 18.5% in the dentate group.
(Table 7).
Table 7: TMD distribution according to type of dentition:
Yes
10
(19.2%)
8
(12.7%)
15
(18.5%)
33
(16.8%)
Edentulous
Partially dentate
Dentate
Total
No
42
(80.8%)
55
(87.3%)
66
(81.5%)
163
(83.2%)
Total
52
(100%0
63
(100%)
81
(100%)
196
(100%)
There was no significant association between resting tongue
position and TMD in the three groups, (Table 8).
Table 8: Resting tongue position distribution in participants with &
without TMD:
Edentulous
TMD
None
Partially dentate
TMD
None
Dentate
TMD
None
*Chi square Test Preformed
Normal
1
(10%)
2
(4.8%)
Abnormal
9
(90%)
40
(95.2%)
Total
10
(100%)
42
(100%)
3
(37.5%)
20
(36.4%)
5
(62.5%)
35
(63.6%)
8
(100%)
55
(100%)
15
(100%)
66
(100%)
0
(0%)
0
(0%)
15
(100%)
66
(100%)
P value
Sig
0.481
Not significant
1.00
Not significant
Fig 3: Resting tongue position distribution in participant with and
without TMD:
120
100
80
62.5%
60
90%
63.6%
95.2%
Abnormal
100%
100%
TMD
No TMD
Normal
40
20
0
10%
4.8%
TMD
No TMD
Edentulous
37.5%
36.4%
TMD
No TMD
Partially dentate
Dentate
3.4 The palatal vault distribution:
In the edentulous subjects the vault of the palate was observed
normal in 34 patients (65.4%), high in11 patients (21.1%), and low in
only 7 patients (13.5%). In the partial dentate group; the vault of the
palate appeared normal in 37 subjects (58.7%), high in 23 subjects
(36.5%), and low in 3 subjects (4.8%). In the dentate group; the normal
was observed in 53 subjects (65.4%), and high in 28 subjects (34.6%)
(Table 9). There was no significant relationship between resting tongue
position and types of palatal vault in different types of dentition (Table
10),
fig.4.(P=
0.447
.
in
comp,
P=o.684
in
par.)
Table 9: The palatal vault distribution:
Normal
34
(65.4%)
37
(58.7%)
53
(65.4%)
124
(63.3%)
Edentulous
Partially dentate
Dentate
Total
High
11
(21.1%)
23
(36.5%)
28
(34%)
62
(31.6%)
Low
7
(13.5%)
3
(4.8%)
0
(0%)
10
(5.1%)
Total
52
(100%)
63
(100%)
81
(100%)
196
(100%)
Table 10: Resting tongue position distribution in different types of
palatal vault:
Edentulous
Normal
High
low
Partially dentate
Normal
High
low
Dentate
Normal
High
low
*Chi square Test Preformed
Normal
2
(5.9%)
0
(0%)
1
(14.3%)
12
(32.4%)
10
(43.5%)
1
(33.3%)
53
(100%)
28
(100%)
0
(0%)
Abnormal
32
(94.1%)
11
(100%)
6
(85.7%)
25
(67.6%)
13
(56.5%)
2
(66.7%)
0
(0%)
0
(0%)
0
(0%)
Total
34
(100%)
11
(100%)
7
(100%)
37
(100%)
23
(100%)
3
(100%)
53
(100%)
28
(100%)
0
(0%)
P value
Sig
0.447
Not significant
0.684
Not significant
-
-
Fig 4: resting tongue position distribution in different types of palatal
vault:
120
100
80
56.5%
67.6%
60
94.1%
66.7%
Abnormal
85.7%
100%
100%
100%
Normal
High
Normal
40
20
0
43.5%
32.4%
5.9%
Normal
33.3%
14.3%
High
low
Normal
Edentulous
High
low
Partially dentate
low
Dentate
3.5. Duration of edentulism and existing denture:
The edentulous subjects who had the last teeth extracted for more
than one year before, were 36 subjects (69.2%), and less than one year
were 16 patients (30.8%). In the partially dentate group, 48 subjects had
at least one tooth extracted for more than one year (78.2%), and the
patients with one tooth extracted for less than one year were 15 (23.8%)
(Table 11). Twenty two of the edentulous subjects were wearing denture
(42.3%), and the patients
were not wearing dentures. In the partial
group; the majority of them 49 (77.7%) did not use a removable partial
denture before (Table 12).
Table 11: Duration of edentulism:
Edentulous
Partially dentate
Total
Long
short
Total
36
(69.2%)
48
(76.2%)
16
(30.8%)
15
(23.8%)
52
(100%)
63
(100%)
84
(73%)
31
(27%)
115
(100%)
Table12: Existing denture in the edentulous groups:
yes
no
total
Edentulous
22
42.3%
30
57.7%
52
(100%)
Partially
dentate
49
77.7%
14
22.3%
63
(100%)
Total
71
44
115
(100%)
In edentulous subjects, the results indicated a significant
association between resting tongue position and duration of edentulism (p
value=0.025), while in partially edentulous subjects there was no
significant relationship between resting tongue position and duration of
edentulism or the wearing denture (Table 13), (Table 14).
Table 13: Association between Resting tongue position & duration of
edentoulism:
Edentulous
Long
Short
Partially dentate
Long
Short
Normal
0
(0%)
3
(18.75%)
17
(35.4%)
6
(40%)
Abnormal
36
(100%)
13
(81.25%)
31
(64.6%)
9
(60%)
Total
36
(100%)
16
(100%)
48
(100%)
15
(100%)
P value
Sig
0.025
significant
0.988
Not significant
*Chi square Test Preformed
Table 14: Association between Resting tongue position & Existence of
denture:
Edentulous
Exist
Not Exist
Partially dentate
Exist
Not Exist
*Chi square Test Preformed
Normal
1
(4.5%)
2
(6.7%)
4
(28.6%)
19
(38.8%)
Abnormal
21
(95.5%)
28
(93.3%)
10
(71.4%)
30
(61.2%)
Total
22
(100%)
30
(100%)
14
(100%)
49
(100%)
P value
Sig
1
Not significant
0.7
Not significant
Fig.5: association between resting tongue position and duration of
edentulism:
120
100
80
64.6%
60
60%
Abnormal
81.25%
Normal
100%
40
20
35.4%
40%
Long
Short
18.75%
0
Long
Short
Edentulous
Partially dentate
Fig 6: association between resting tongue position and existence of
denture:
120
100
80
71.4%
60
95.5%
61.2%
Normal
93.3%
40
20
28.6%
0
4.5%
6.7%
Exist
Not Exist
Edentulous
Abnormal
Exist
38.8%
Not Exist
Partially dentate
3.6:Kennedy's classification among partially dentate participants:
More than halve of the partially edentulous subjects were
classified as classI; 34 (54%), where as a low number of the participants
were classified as class IV (Table 15), no significant relationship was
found (Table16).
Table 15:Kennedy's classification among partially dentate
participants:
Frequency
Percent
Class I
34
54%
Class II
12
19%
Class III
10
15.9%
Class IV
7
11.1%
Total
63
100%
Table 16: Association between Resting tongue position & Kennedy's
classification among partially dentate participants:
Class I
Class II
Class III
Class IV
Total
*Chi square Test Preformed
** p value=.789.
Normal
12
(35.3%)
4
(33.3%)
5
(50%)
2
(28.6%)
23
(36.5
Abnormal
22
(64.7%)
8
(66.7%)
5
(50%)
5
(71.4%)
40
(63.5%)
Total
34
(100%)
12
(100%)
10
(100%)
7
(100%)
63
(100%)
Fig.7: Association between Resting tongue position & Kennedy's
classification among partially dentate participants:
120
100
80
50%
64.7%
66.7%
71.4%
60
Abnormal
Normal
40
50%
20
35.3%
33.3%
Class I
Class II
28.6%
0
Class III
Class IV
3.7.The distribution of number of extracted teeth among partially
dentate;
The mean number of extracted teeth was 7.29, ranging from two
teeth to thirteen with a median value of eight teeth, (Tables 17 and 18).
According to the results there was a significant association
between resting tongue position and the mean number of extracted teeth
in partially edentulous subjects (P value= 0.001).
Table 17: Number of extracted Teeth among partially edentulous:
Mean
7.29
Mode
7
Std. Deviation
2.02
Minimum
2
Maximum
13
Table 18: Number of extracted teeth:
No. of Teeth
2
4
5
6
7
8
9
10
11
12
13
Total
Frequency
1
3
7
11
15
8
12
2
2
1
1
63
Percent
1.6%
4.8%
11.1%
17.4%
23.8%
12.7%
19%
3.2%
3.2%
1.6%
1.6%
100%
Table 19: Association between Resting tongue position & Mean
number of extracted teeth in partially dentate participants:
Normal
N
Mean
Std. Deviation
23
5.8
1.6
8.2
1.7
Abnormal
40
*Independent samples T test preformed
** p value=.0001, significant
3.8:Angle's classification among dentate participants:
87.7% were identified as Angle class I ,8.6%as class II, and 3.7%
as class III. (Table 21).
Table 20: Angle's classification among dentate participants:
Class I
Frequency
71
Percent
87.7%
Class II
7
8.6%
Class III
3
3.7%
Total
81
100%
The sub-classification between upper and lower positions did not
seem
to
have
any
statistical
significance
(Tables
22-27).
Table21:Upper and lower Resting tongue position distribution in
participants with & without TMD:
normal
upper
1
(10%)
0
(0%)
normal
lower
0
(0%)
2
(4.8%)
abnormal
upper
3
(30%)
22
(52.4%)
abnormal
Total
lower
6
10
(60%)
(100%)
18
42
(42.9%) (100%)
3
(37.5%)
11
(20%)
0
(0%)
9
(16.4%)
1
(12.5%)
24
(43.6%)
4
(50%)
11
(20%)
8
(100%)
55
(100%)
9
(60%)
None
24
(36.4%)
*Chi square Test Preformed
6
(40%)
42
(63.6%)
0
(0%)
0
(0%)
0
(0%)
0
(0%)
15
(100%)
66
(100%)
Completely Edentulous TMD
None
Partially Edentulous
TMD
None
Dentate
TMD
P value
sig
0.11
Not significant
0.085
Not significant
0.164
Not significant
Table 22: Upper and lower Resting tongue position distribution in
different types of palate vault:
normal
upper
normal
lower
abnormal
upper
abnormal
lower
Total
1
1
17
15
34
(2.9%)
0
(0%)
0
(0%)
(2.9%)
0
(0%)
1
(14.3%)
(50%)
7
(63.6%)
1
(14.3%)
(44.1%)
4
(36.4%)
5
(71.4%)
(100%)
11
(100%)
7
(100%)
8
4
12
13
37
(21.6%)
6
(26.1%)
0
(0%)
21
(10.8%)
4
(17.4%)
1
(33.3%)
32
(32.4%)
11
(47.8%)
2
(66.7%)
0
(35.1%)
2
(8.7%)
0
(0%)
0
(39.6%)
High
12
(42.9%)
Low
0
(0%)
*Chi square Test Preformed
(60.4%)
16
(57.1%)
0
(0%)
(0%)
0
(0%)
0
(0%)
(0%)
0
(0%)
0
(0%)
Completely
Edentulous
Normal
High
Low
Partially
Edentulous
Normal
High
Low
Dentate
Normal
P value
sig
0.4
Not
significant
(100%)
23
(100%)
3
(100%)
53
0.2
Not
significant
(100%)
28
(100%)
0
(100%)
0.965
Not
significant
Table 23:Association between upper and lower Resting tongue
position & duration of edentoulism:
Completely
Edentulous
Partially
Edentulous
normal
upper
normal
lower
abnormal
upper
abnormal
lower
Total
Long
0
0
19
17
36
Short
(0%)
1
(6.25%)
(0%)
2
(12.5%)
(52.8%)
6
(37.5%)
(47.2%)
7
(43.75%)
(100%)
16
(100%)
Long
9
8
21
10
48
Short
(18.7%)
5
(33.3%)
(16.7%)
1
(6.7%)
(43.8%)
4
(26.7%)
(20.8%)
5
(33.3%)
(100%)
15
(100%)
P value
sig
0.062
Not
significant
0.3
Not
significant
Table 24:Association between upper and lower Resting tongue
position & Existence of denture:
Completely
Edentulous
Exist
Not
Exist
Partially
Edentulous
Exist
normal
upper
normal
lower
abnormal
upper
abnormal
lower
Total
0
1
10
11
22
(0%)
(4.5%)
(45.5%)
(50%)
(100%)
1
(3.3%)
1
(3.3%)
15
(50%)
13
(43.3%)
30
(100%)
3
1
5
5
14
(21.4%)
(7.1%)
(35.7%)
(35.7%)
(100%)
8
(16.3%)
20
(40.8%)
10
(20.4%)
49
(100%)
Not
Exist
11
(22.4%)
*Chi square Test Preformed
P value
sig
0.811
Not
significant
0.6
Not
significant
Table 25:Association between upper and lower Resting tongue
position & Kennedy's classification among partially dentate
participants:
normal
upper
Class I
7
(20.6%)
Class II
3
(25%)
Class III
2
(20%)
Class IV
2
(28.6%)
Total
14
(22.2%)
*Chi square Test Preformed
normal
lower
5
(14.7%)
1
(8.3%)
3
(30%)
0
(0%)
9
(14.3%)
abnormal
upper
12
(35.3%)
6
(50%)
2
(20%)
5
(71.4%)
25
(39.7%)
abnormal
lower
10
(29.4%)
2
(16.7%)
3
(30%)
0
(0%)
15
(23.8%)
Total
34
(100%)
12
(100%)
10
(100%)
7
(100%)
63
(100%)
Table 26 :Association between upper and lower resting tongue
position & Angle's classification in Dentate participants:
normal upper
normal lower
Total
29
(40.8%)
4
(57.1%)
0
(0%)
42
(59.2%)
3
(42.9%)
3
(100%)
71
(100%)
7
(100%)
3
(100%)
33
(40.7%)
*Chi square Test Preformed
48
(59.3%)
81
(100%)
Class I
Class II
Class III
Total
Chapter Four
DISCUSSION,
CONCLUSION
&
RECOMMENDATIONS
4-1 DISCUSSION
The present study that the prevalence of abnormal positions of the
tongue was different among the three groups; edentulous lower jaw
patients, partially dentate patients, and dentate subjects. By producing a
set of distinct criteria and some clear indications about potentially critical
parameters, the previous studies provided the basis for the areas
investigated in the current study. The prevalence of abnormal tongue
positions has been reported by several authors as either 25%(1,7,70,74) or
35%(2,8,13,69,73).
No abnormality of tongue position in dentate group was detected,
while 94.2% of the edentulous subjects was appeared to have with
abnormal position of the tongue at rest, as where only three had normal
position of the tongue (Table 10).The sub-classification between upper
and lower positions did not seem to have any significance (Table21-27).
Both sexes in the three groups were represented sufficiently (Table 3),
and no significant relationship with the resting tongue position was found
(Table 6).
The results revealed significant differences among age distributions
of the three groups (Table 4). Within partially dentate individuals there
was a significant relationship between age distribution and tongue
position at rest (Table7) (P=0.001). In the edentulous lower jaw there
was no significant relationship between age and resting position of tongue
because the majority of them showed an abnormal tongue position, and so
did the dentate,i.e. none of them had abnormal position of tongue at rest.
The aging process as many authors state, induces anatomical changes in
the mouth, such as inferior movement of the hyoid bone, reduction of
pharyngeal airway space and increase of the tongue volume
79).
(76, 77, 78,
The mean age of completely edentulous subjects was 65.25, while the
partially edentulous subjects covered an extensive age span of 56-year
(range 20-76), this have lead to variable modifications of oral anatomy in
the partial group. The dentate group consisted of younger subjects so no
anatomical changes due to aging process were observed.
In a study by Kotsiomiti et al
(63)
.
, no a significant relationship
between age, and tongue position was found.They stated that, the
possibility of a relationship between tongue position and age cannot be
rejected.
.
The present study indicated that there was no association between
TMD and resting tongue position (Table 9). In previous studies it has
been emphasized that a patient with TMJ dysfunction should avoid lifting
the tongue against the palate due to pain in the masticatory muscle or
TMJ region, leading to an abnormal position (85,86) .
The results showed no significant association between tongue
position and vault of the palate in the three groups (Table 11). Many
studies have reported that the upper or lower normal position of the
tongue can be influenced by the palatal vault (71). The tongue pressure is
gradually distributed on the palatal surface during swallowing in adult
subjects with normal oral function and occlusion, i.e., weaker pressure is
exerted anteriorly, whereas stronger pressure is exerted posteriorly (92).
In edentulous subjects the results showed an association between
tongue position and duration of edentulism i.e. if teeth had been extracted
recently or a long time ago (Table14). The use of complete denture,
which restores normal tongue space, does not result in increased
percentages of normal position (Table15). These findings are in
agreement with several previous studies
(63, 62)
. The results showed that
there were no association neither between Kenndy's classification of
partially dentate patients and tongue position at rest, nor between Angle's
classification of dentate subjects and resting tongue position. In previous
studies as explained by Proffit, the resting pressure of the tongue is one of
the primary factors in the maintenance of dental equilibrium
(88)
. In
addition, it has been suggested that the resting tongue position in subjects
with skeletal open bites appears to be related to the position of the
incisors
(89)
.This statement cannot compared to this study , because the
majority of the dentate group had a normal Angle's class I.
In this study the number of existing lower teeth was the
predominant factor, that is the more teeth were missing in the lower jaw,
the more frequently the retracted tongue was noticed (Table 2). These
findings were in agreement with findings of Kotsiomiti et al
(63)
, who
commented that the anatomical changes which occurred following tooth
loss may be linked to establishment of an abnormal resting tongue
through their constant modified function of oral musculature and
alterations of the space available for the tongue .
Occurrence of the abnormal tongue position was clear in the
completely and partially edentulous in the lower jaw (Table2), but the
study did not prove any significant relationship when compared with
denture function, because edentulous patients with dentures did n't differ
from patients who were n't wearing dentures.
Many studies used the criteria given by Wright et al.
(69)
, which was
also used it in this study. Although it can be debated whether the
observed position actually represents the most relaxed state of the
complex tongue musculature, the above procedure was employed in other
studies, because it was the most practical, convenient and was able to
produce a highly reproducible outcome.
Many studies stated that a retracted tongue represents a considerable
drawback in constructing a functional denture
(2, 8, 13, 75, and 76)
. This is
because, the tongue tends to retract on opening, the anterior lingual sulcus
is distorted and the muscles of the floor of the mouth become tensed, so
the flanges and extensions are difficult to estimate, and the peripheral seal
cannot be obtained.
Other studies, have confirmed the high prevalence of abnormal
resting position in the edentulous subjects, but could not, give any
definite
conclusion
on
its
effect
on
denture
function
(63)
.
4-2 CONCLUSION
The abnormal position of the tongue at rest is increasingly observed
with decreasing number of natural teeth. The presence of a retracted
tongue affects the complete denture construction; however, its effect on
denture function remains questionable, and needs further investigations.
Although the duration of edentulism in the edentulous had a
significant relation with abnormal position of the tongue, it does not mean
that we can stop retracting normal tongue by constructing a denture as
soon as extraction occurred.
4-3 RECOMMENDATIONS
1. Increasing sample size in future study may lead to more accurate
results about the relation between tongue position and the state of
dentition.
2. Correlation between tongue position and other clinical variables
may
be
of
great
interest,
so
further
investigations
are
recommended.
3. For functional ability of denture wearer, training exercises are
recommended.
4.
Conservative treatment of natural teeth reduces the hazard of loss
of the teeth which can lead to modified oral environment.
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Appendix-1
University of Khartoum
Faculty of Dentistry
Department of Prosthodontics
Examination Sheet
Patient name:
Age:
Sex:
♂
♀
Examination methods:
Extraoral examination:
TMJ:
Joint sound.
Yes
No
Muscles, joint palpitation.
Tenderness.
Yes
No
Pain.
Yes
No
Limitation of jaw movement. Yes
No
Intraoral examination:
Number and position of existing teeth (Kenndy classification).
I
II
Duration of edentoulism.
Existing dentures.
III
IV
Long
short
Yes
No
Vault of palate;
normal,
high,
low.
Resting tongue position,(estimates at the beginning and end of interview)
Criteria with;( Table 2)
1.The extent by which the floor is visible.
2.Lateral borders,in relation to the lingual surface of teeth, or lingual
sides of the ridge.
3.Apex of tongue in relation to the lingual surfaces of teeth or lingual
sides of the ridge.
Table No 1;
Group
1.completely
edentulous
2.Partially
edentulous.
3.Dentate
No
Sex
Age
Table No 2;
Criteria
Resting
Floor of the
Lateral borders of the
Apex of the tongue
tongue
mouth
tongue
Not visible
Over occlusal surfaces or
Behind/on lingual
on the ridge.
surfaces or on the
Next to lingual surfaces or
ridge
inside the ridge.
Behind lingual
Over occlusal surfaces or
surfaces or behind
behind the end of ridge.
the ridge
Behind posterior teeth or
Withdrawn into the
next to the end of ridge.
body
position
1-Normal
upper
2-Normal
Not visible
lower
3-Abnormal
Visible
upper
4-Abnormal
lower
Visible
Pointing to the floor
of the mouth
‫‪Appendix-2‬‬
‫ﺠﺎﻤﻌﺔ ﺍﻟﺨﺭﻁﻭﻡ‬
‫ﻜﻠﻴﺔ ﻁﺏ ﺍﻻﺴﻨﺎﻥ‬
‫ﻗﺴﻡ ﺍﻻﺴﺘﻌﺎﻀﺔ ﺍﻟﺼﻨﺎﻋﻴﺔ‬
‫ﺍﺴﺘﻤﺎﺭﺓ ﻤﻭﺍﻓﻘﺔ ﻟﻠﻤﺸﺎﺭﻜﺔ ﻓﻰ ﺍﻟﺒﺤﺙ‬
‫ﻴﻘﻴﻡ ﻗﺴﻡ ﺍﻻﺴﺘﻌﺎﻀﺔ ﺍﻟﺼﻨﺎﻋﻴﺔ ﻜﻠﻴﺔ ﻁﺏ ﺍﻻﺴﻨﺎﻥ ﺠﺎﻤﻌﺔ ﺍﻟﺨﺭﻁﻭﻡ ﺒﺎﻟﺘﻌﺎﻭﻥ ﻤﻊ ﻤﺠﻠـﺱ‬
‫ﺍﻟﺩﺭﺍﺴﺎﺕ ﺍﻟﻁﺒﻴﺔ ﺍﻟﻌﻠﻴﺎ ﺒﺤﺜﺎ ﻟﻤﻌﺭﻓﺔ ﺍﻟﻭﻀﻊ ﺍﻟﻁﺒﻴﻌﻰ ﻟﻠﻠﺴﺎﻥ ﺍﻻﻨﺴﺎﻥ ﻭﻋﻼﻗﺘﻪ ﺒﻔﻘﺩﺍﻥ ﺍﻻﺴـﻨﺎﻥ‬
‫ﻤﻥ ﺨﻼل ﻓﺤﺹ ﺍﻜﻠﻴﻨﻴﻜﻰ ﺭﻭﺘﻴﻨﻰ ﻟﻠﻤﺭﻀﻰ ﺍﻟﻤﺘﺭﺩﺩﻴﻥ ﻋﻠﻰ ﻋﻴﺎﺩﺓ ﺍﻻﺴﻨﺎﻥ ﻜﻠﻴﺔ ﻁﺏ ﺍﻻﺴـﻨﺎﻥ‬
‫ﺠﺎﻤﻌﺔ ﺍﻟﺨﺭﻁﻭﻡ ﻭﻁﻼﺏ ﺍﻟﺼﻔﻴﻥ ﺍﻟﺭﺍﺒﻊ ﻭﺍﻟﺨﺎﻤﺱ ﺒﺎﻟﻜﻠﻴﺔ ﺒﻨﺎﺀﺍ ﻋﻠﻲ ﻤﺎﺘﻡ ﺫﻜﺭﻩ ﺍﻗـﺭ ﻤـﻭﺍﻓﻘﺘﻲ‬
‫ﺍﻟﺸﺨﺼﻴﺔ ﻜﻤﺘﻁﻭﻉ ﻓﻲ ﺍﻟﺒﺤﺙ ﺍﻟﻤﻌﻨﻲ ﻋﻠﻲ ﺍﻻﺘﺴﺘﺨﺩﻡ ﺍﻟﻨﺘﺎﺌﺞ ﻟﻐﻴﺭ ﺍﻫﺩﺍﻑ ﺍﻟﺩﺭﺍﺴﺔ‪.‬‬
‫اﻻﺳﻢ‪.........................................................:‬‬
‫اﻟﺘﻮﻗﻴﻊ‪........................................................:‬‬
Appendix-3
‫ﺑﺴﻢ اﷲ اﻟﺮﺣﻤﻦ اﻟﺮﺣﻴﻢ‬
Approval Letter
To: The Dean of Faculty of Dentistry, University of Khartoum
Dear Sir,
In our effort to evaluate the dental health of our society, an assuring
quality services to our patients. I request your permission on conducting
my research on:
Resting Tongue Position and its Relation
To the State of Dentition among Sample
of Sudanese Population
I submit my application hoping for your permission on support. This
research is a requirement to fulfill my Medical M.Sc.
Thanks
Sincerely,
Dr. Rasha Afifi Mhd Saeed.