1. No category

Journal of Medicine, Radiology, Pathology & Surgery (2015), 1, 5–8
ORIGINAL ARTICLE
Radiographic study of mental foramen type and position
in Bangalore population
Navya N. Swamy, Tejavathi Nagaraj, Noori Ghouse, C. D. Jagadish, N. Sreelakshmi, Rahul Dev Goswami
Department of Oral Medicine and Radiology, Sri Rajiv Gandhi Dental College & Hospital, Bengaluru, Karnataka, India
Keywords
Mandibular canal, mental foramen,
panoramic radiograph
Correspondence Dr. Navya N. Swamy, Department of
Oral Medicine and Radiology, Sri Rajiv
Gandhi Dental College and Hospital,
Cholanagar, Bengaluru - 560 032,
Karnataka, India. Phone: +91-9686633552,
Email: [email protected]
Received 03 November 2014;
Accepted 29 December 2014
doi: 10.15713/ins.jmrps.2
Abstract
Background: The mental foramen is defined as the entire funnel-like opening in the
lateral surface of the mandible at the terminus of the mental canal. The mental foramen
marks the termination of mandibular canal in the mandible, through which the inferior
alveolar nerve and vessels pass. Position of the mental foramen is important when
administering regional anesthesia. The aim of this study was to determine the most
common type and position of mental foramen in Bangalore population using digital
panoramic radiographs.
Materials and Methods: A total of 100 (50 M and 50 F) digital panoramic radiographs
were collected from Department of Oral Medicine and Radiology within age of
15‑50 years, type and position of mental foramen was analyzed.
Results: The most common occurrence is Type I and position 4 (symmetrical) of mental
foramen. Comparison of type in males and females appears significant. Comparison of
the position in males and females appears not significant.
Conclusion: The following study suggests that clinicians should carefully identify
mental foramen thus minimizing complications during implant, orthognathic surgery
and treatment of maxillofacial injuries.
Introduction
Knowing the location of the mental foramen is very important
when considering placing implants or any other surgical
procedure in the foraminal region.[1] Mental foramen is a small
foramen situated in the anterolateral aspect of the body of the
mandible.[2]
The mental foramen is defined as the entire funnel-like
opening in the lateral surface of the mandible at the terminus
of the mental canal [Figure 1].[3] This foramen is contained
entirely within the buccal cortical plate of bone. The average
size of the foramen is 4.6 mm horizontally and 3.4 mm vertically
on the lateral surface of the mandible.[4] The foramen is usually
larger on the left side of the mandible.[5] Schaeffer stated that
mental foramen was located between the spaces of mandibular
premolars.[6]
Mental foramen`s anatomical position is of significant
importance in giving local anesthesia, treatments of fractures
related to parasymphysis area, osteotomies required for
orthognathic and implant placement, giving complete denture in
mandible etc.[7] Inferior alveolar nerve gives mental and incisive
branch inside the canal. Mental nerve emerges from mental
Figure 1: Orthopantomogram showing type and position of mental
foramen
foramen and supply sensory innervations to the soft tissues
of the chin, lower lip and gingival on the ipsilateral side of the
mandible.[8]
Yosue and Brooks classified into four types[9]
Type I: Mental canal is continuous with the mandibular canal.
Type II: The foramen is distinctly separated from the mandibular
canal.
Journal of Medicine, Radiology, Pathology & Surgery ● Vol. 1:1 ● Jan-Feb 20155
Swamy, et al.
Radiographic study of mental foramen
Type III: Diffuse with a distinct border of the foramen.
Type IV: “Unidentified group.”
Position 1: Situated anterior to the first premolar.
Position 2: In line with the first premolar.
Position 3: Between the first and second premolar.
Position 4: In line with second premolar.
Position 5: Between the second premolar and first molar.
Position 6: In line with the first molar.
The accurate identification of the mental foramen is important
for both diagnostic and clinical procedures. The radiographic
appearance of the mental foramen may result in a misdiagnosis
of a radiolucent lesion in the apical area of mandibular premolar
teeth.[10] Hence, the aim of this study was to determine the most
common type and position of mental foramen in Bangalore
population using digital panoramic radiographs.
Chi-square test. The most common Type I is mental canal
is continuous with the mandibular canal of mental foramen
(53.5%), followed by Type III diffuse with a distinct border of
the foramen (31.5%), Type II the foramen is distinctly separated
from the mandibular canal (14.0%) Type IV unidentified group
(1%) [Table 1].
The most frequent position 4 is in line with second premolar
of mental foramen (63.5%). The second common position
was position 3 between first and second premolar (23.0%)
followed by position 5 between the second premolar and first
molar (9.0%), position 2, in line with the first premolar (3.5%),
position 1 situated anterior to the first premolar, position 6 in
line with the first molar (0%) [Table 2].
Comparison of type in males and females appears significant.
Comparison of the position in males and females appears not
significant. Sex analysis showed a higher female percentage of
60% in Type I [Graph 1]. Sex analysis showed a higher female
percentage of 84% in position 4 [Graph 2].
Materials and Methods
Discussion
The position of the image of the mental foramen was
recorded as follows[9]
The radiographs were chosen according to the following
criteria
Mental foramen is a key factor in many of the surgical as well
as clinical procedures in routine clinical practice.[11] Mental
foramen represents the termination of the mental canal.[12] The
mental nerve passes through the mental foramen, supplying
sensory innervation to the lower lip, buccal vestibule, and gingiva
mesial to the first mandibular molar.[13] The mental foramen has
been reported to vary in position in different ethnic groups.[14]
Knowing the site of the mental foramen allows for accurate
delivery of local anesthesia of terminal incisive branches
of the inferior alveolar nerve. The mental bundle can be
traumatized during surgical procedures, such as periapical
Inclusion criteria
Table 1: Distribution of type in males and females
Total of 100 (50 M and 50 F) digital panoramic radiographs were
collected from Department of Oral Medicine and Radiology
within age of 15-50 years who were advised for radiographs
for various purposes, ethical clearance was obtained. Type
and position of mental foramen was analyzed. All panoramic
radiographs were taken by Sirona panoramic machine. The
magnification factors reported by the manufacturers were 1.2
and 1.25, respectively.
• All mandibular teeth from the right first molar to the left first
molar were present
• Erupted teeth
• The films must be free from any radiolucent or radiopaque
lesion in the lower arch and showed no radiographic exposure
or processing artifacts.
Type
Exclusion criteria
Total
• Radiographs in which the lower teeth (between 36 and 46)
were missing, had deep caries, root canal treatment or various
restorations were eliminated because of a possible associated
periapical radiolucency
• Radiographs that showed the lower canine was missing were
excluded because of the possibility of mesial premolar drift
• Panoramic radiographs in which the mental foramen could
not be identified were excluded.
Results
In 100 panoramic radiographs of mental foramen, most common
type and position was studied and recorded by performing
6
Total
n (%)
χ2
P value
1
Gender (n (%))
Male
Female
46 (46.0)
61 (61.0)
107 (53.5)
9.976
0.019**
2
13 (13.0)
15 (15.0)
28 (14.0)
3
41 (41.0)
22 (22.0)
63 (31.5)
4
0 (0.0)
2 (2.0)
2 (1.0)
100 (100.0)
100 (100.0)
200 (100.0)
**Significant
Table 2: Distribution of position in males and females
Gender (n (%))
Male
Female
2 (2.0)
0 (0.0)
2 (2.0)
Total
n (%)
χ2
P value
2 (1.0)
4.296
0.371*
5 (5.0)
7 (3.5)
22 (22.0)
24 (24.0)
46 (23.0)
63 (63.0)
64 (64.0)
127 (63.5)
11 (11.0)
7 (7)
18 (9)
100 (100)
100 (100)
200 (100)
*Not significant
Journal of Medicine, Radiology, Pathology & Surgery ● Vol. 1:1 ● Jan-Feb 2015
Swamy, et al.
Radiographic study of mental foramen
0«
)«
7\SHV
Graph 1: Distribution of types in male and female
0«
)«
3RVLWLRQ
Graph 2: Distribution of position in male and female
surgery, extraction of impacted teeth, enucleation of cyst or
tumor, and so on, resulting in paresthesia or anesthesia in the
area innervated by the nerve.[15] It also aids in interpreting
anatomical landmarks in oral pathology and forensics.[16]
Although it is often possible to identify the mental foramen
radiographically, knowing the normal range of possible
locations is essential. The location of the mental foramen has
been studied in different populations.[9]
In our study, out of 100 panoramic radiographs, the
most common Type I is mental canal is continuous with the
mandibular canal of mental foramen (53.5%) followed by
Type III diffuse with a distinct border of the foramen (31.5%).
The most common position for the mental foramen was in line
with the second premolar in 63.5%, followed by between the
first and second premolars in 23.0%; thus these two positions
accounted for 86.5% of the cases.
Our results were in accordance with previous studies in other
populations showing that the most common type for the mental
foramen is continuous with the mandibular canal followed by
diffuse with distinct border of foramen[4] and in a position aligned
with the second premolar, followed by a position between the
first and second mandibular premolars.[17-20]
This position is consistent with findings of Yosue and
Brooks[4] in relation to types of mental foramen and in relation to
position Agarwal and Gupta,[21] Prabodha and Nanayakkara[22]
Neo[23] and Gupta and Soni.[2] The same position was observed
in Tanzanian adult black male,[24] Malay population[9]
Brazilian,[25] Sankar et al.,[26] Malawian mandible,[27] Ukoha[28]
in south eastern Nigerian Singh et al.[29] and Kanta et al. Jasser
and Nwoku observed most common position as in line with
the longitudinal axis of second premolar closely followed by
location between first and second premolar in radiographic
study of Saudi Arabians.[30]
Panoramic radiographs were used in this study because the
mental foramen was seen more consistently on the wide field
of view in panoramic radiographs of the mandible than on
periapical radiographs. A weakness of our study is the use of
panoramic radiographs for localization of the mental foramen
instead of the use of an anatomic study on skulls. panoramic
radiographs showed a greater displacement of the foramen
compared with anatomical measurements; however, the
difference in the horizontal position found by the two methods
was not statistically significant. Further anatomical studies using
skulls should be conducted in a Bangalore population. The
limitations of this study are small sample size. A larger sample
size would also enable a more detailed assessment of the position
and type of mental foramen.
Conclusion
The present study reveals valuable insights on the information
concerning the type and position of mental foramen in
Bangalore population. The following study suggests that
clinicians should carefully identify mental foramen thus
minimizing complications during implant, orthognathic surgery
and treatment of maxillofacial injuries. Hence, our study may
provide the necessary data of mental foramen among population
and may be useful for the surgeons, anesthetists, neurosurgeons
and dentists to carry out procedures without complications.
Clinical significance
Position of the mental foramen is important when administering
regional anesthesia. Mental foramen identification and
preservation of mental nerve during.
• Periapical surgery
• Implant surgery
• Maxillofacial trauma
• Orthognathic procedures.
References
1. Al-Juboori MJ, Hua CM, Yuen KY. The importance of the mental
foramen location detection by using different radiographic
technique: Mini review. Int J Med Imaging 2014;2:63-8.
2. Gupta S, Soni JS. Study of anatomical variations and incidence
of mental foramen and accessory mental foramen in dry human
mandibles. Natl J Med Res 2012;2:28-30.
Journal of Medicine, Radiology, Pathology & Surgery ● Vol. 1:1 ● Jan-Feb 20157
Radiographic study of mental foramen
3.Muhammad DA. Anteroposterior position of the mental
foramen on panoramic radiographs in Sulaimani population.
Kurdistan Acad J 2009;8:9-16.
4. Yosue T, Brooks SL. The appearance of mental foramina on
panoramic and periapical radiographs. II. Experimental
evaluation. Oral Surg Oral Med Oral Pathol 1989;68:488-92.
5. Yosue T, Brooks SL. The appearance of mental foramina on
panoramic radiographs. Experimental evaluation. Oral Surg
Oral Med Oral Pathol 1989;68:488-92.
6. Rai R, Shrestha S, Jha S. Mental foramen: A morphological and
morphometrical study. Int J Healthc Biomed Res 2014;2:144-50.
7. Aher V, Pillai P, Ali FM, Mustafa M, Ahire M, Mudhol A, et al.
Anatomical position of mental foramen: A review. Glob J Med
Public Health 2012;1:61-4.
8. Roy PP, Ambali MP, Doshi MA, Jadhav SD. Variation in the
position shape and direction of mental foramen in dry mandible.
Int J Anat Res 2014;2:418-20.
9. Ngeow WC, Yuzawati Y. The location of the mental foramen in a
selected Malay population. J Oral Sci 2003;45:171-5.
10.Phillips JL, Weller RN, Kulild JC. The mental foramen: 1. Size,
orientation, and positional relationship to the mandibular
second premolar. J Endod 1990;16:221-3.
11.Seema S, Bhavana D, Kamlesh T, Penci CA. Morphometric
analysis of mental foramen in human mandibles of Gujarat
region. Int J Sci Res 2014;3:36-7.
12.Green RM. The position of the mental foramen: A comparison
between the southern (Hong Kong) Chinese and other
ethnic and racial groups. Oral Surg Oral Med Oral Pathol
1987;63:287‑90.
13.Moiseiwitsch JR. Position of the mental foramen in a North
American, white population. Oral Surg Oral Med Oral Pathol
Oral Radiol Endod 1998;85:457-60.
14.Koppe T. Summary of: A comparative anthropometric study
of the position of the mental foramen in three populations. Br
Dent J 2012;212:188-9.
15.Haghanifar S, Rokouei M. Radiographic evaluation of the
mental foramen in a selected Iranian population. Indian J Dent
Res 2009;20:150-2.
16.Shankland WE 2nd. The position of the mental foramen in Asian
Indians. J Oral Implantol 1994;20:118-23.
17.Miller JA Jr. Studies on the location of the lingula, mandibular
foramen and mental foramen. Anat Rec 1953;115:349.
18.Matsuda Y. Location of the dental foramina in human skulls
8
Swamy, et al.
from statistical observations. Int J Orthod Oral Surg Radiogr
1927;13:299-305.
19.Tebo HG, Telford IR. An analysis of the variations in position of
the mental foramen. Anat Rec 1950;107:61-6.
20.Mwaniki DL, Hassanali J. The position of mandibular and
mental foramina in Kenyan African mandibles. East Afr Med J
1992;69:210-3.
21.Agarwal DR, Gupta SB. Morphometric analysis of mental
foramen in human mandibles of South Gujarat. People’s J Sci
Res 2011;4:15-8.
22.Prabodha LB, Nanayakkara BG. The position, dimensions and
morphological variations of mental foramen in mandible. Galle
Med J 2006;11:13-5.
23.Neo J. Position of the mental foramen in Singaporean Malays
and Indians. Anesth Prog 1989;36:276-8.
24.Fabian FM. Position, shape and direction of opening of the
mental foramen in dry mandibles of Tanzanian adult black
males. Ital J Anat Embryol 2007;112:169-77.
25.Maise MA, Felippe BP. The mental foramen position in
dentate and edentulous Brazilian’s mandible. Int J Morphol
2008;26:981 7.
26.
Sankar DK, Bhanu SP, Susan PJ. Morphometrical and
morphological study of mental foramen in dry dentulous
mandibles of South Andhra population of India. Indian J Dent
Res 2011;22:542-6.
27.Igbigbi PS, Lebona S. The position and dimensions of the
mental foramen in adult Malawian mandibles. West Afr J Med
2005;24:184-9.
28.Ukoha UU. Position, shape and direction of the mental
foramen in mandibles South-Eastern Nigeria. Int J Biomed Res
2013;4:499-503.
29.Singh SK, Gopinathan K. Variation in position and number of
mental foramen in mandibles of north Indian population J Anat
Soc India 1992;41:47-51.
30.al Jasser NM, Nwoku AL. Radiographic study of the mental
foramen in a selected Saudi population. Dentomaxillofac Radiol
1998;27:341-3.
How to cite this article: Swamy NN, Nagaraj T, Ghouse N,
Jagadish CD, Sreelakshmi N, Goswami RD. Radiographic study
of mental foramen type and position in Bangalore population.
J Med Radiol Pathol Surg 2015;1:5-8.
Journal of Medicine, Radiology, Pathology & Surgery ● Vol. 1:1 ● Jan-Feb 2015