Introduction
Temporomandibular joint (TMJ) functioning involves a complex mechanism of the muscles
of mastication, ligaments, and the bones of the joint which when work in a synchrony
bring about fluidity in the movement of the jaw for its various activities. Owing
to this, a small flaw in these mechanisms can overstress a particular area and bring
about a compensatory change in the function to meet the demands. Depending on the
threshold of the patients and the severity, these compensatory changes may be perceived
as a discomfort, disability, and restriction in function.[1]
Temporomandibular disorders (TMDs) are considered to be the most commonly occurring
type of orofacial pain.[2] Patients who report presenting with TMD may not complain of tenderness or discomfort
specific to the area of the joint. Hence, appropriate understanding of the basic physiology
and pathology of the TMJ is needed to diagnose the pain or disorder to be related
to the joint and plan the treatment or send for an appropriate referral.
Undergraduate students who move on to be general dental practitioners require this
basic understanding to recognize and diagnose a case pertaining to the joint and also
understand the treatment plan or refer to a specialist in the field.
Hence, this present survey was undertaken to understand the awareness among undergraduate
students undergoing their residency program regarding the anatomy, physiology, pathology,
diagnosis, and treatment pertaining to the TMJ.
Results
The results were analyzed using IBM SPSS Statistics Version 22 (IBM Corp., Armonk,
New York, United States). Number of students giving correct answer was identified
and the percentage was calculated. These results are presented in bar diagrams ([Figs. 1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]). The results were further grouped under sections of anatomy (Q1-Q4), physiology
(Q5-Q9), pathology (Q10-Q12), diagnosis (Q13-15), treatment planning (Q16-Q19), and
attitude (Q20), and the calculated percentage of correct answers of each question
were presented in a cluster bar diagram ([Fig. 21]). Mean and standard deviation of the percentage value was computed according to
the sections of the questionnaire. Note that 71.75% ± 6.13% of students answered anatomy
questions correctly, 46.6% ± 28% answered physiology questions correctly, 34.67% ±
5.5% answered pathology questions correctly, 23.67% ± 2.5% answered diagnosis questions
correctly, and 27.25% ± 15.8% answered questions of treatment plan correctly. Note
that 100% of them understood the importance of TMJ in dentistry.
Fig. 1 How many bones is the Temporomandibular Joint made up of?
Fig. 2 What is the Articular disc made up of?
Fig. 3 Which is/are the Muscles of Mastication?
Fig. 4 Which is/are the accessory ligaments of temporomandibular joint?
Fig. 5 What is the function of Ligaments of temporomandibular joint?
Fig. 6 What does the condyle articulate with during normal function?
Fig. 7 Which movement is seen in the temporomandibular joint?
Fig. 8 Which muscle aids closing of mouth?
Fig. 9 Which muscle aids the opening of mouth?
Fig. 10 Disorders of the temporomandibular joint is seen only with temporal bone, condyle
and disc.
Fig. 11 Which symptoms can be presented as a temporomandibular joint disorder?
Fig. 12 What can cause restriction in mouth opening?
Fig. 13 What is a patient presenting with acute pain on right side of the angle of the mandible
after class II cavity restoration in 46 likely to have?
Fig. 14 What is a patient presenting with a click sound while opening mouth likely to have?
Fig. 15 Which scan provides the best radiologic view for examination of temporomandibular
joint?
Fig. 16 What is the treatment for disorders of temporomandibular joint?
Fig. 17 Which occlusal relation is ideal for restoration of single tooth in complete dentate
patient?
Fig. 18 Which occlusal relation is advocated for selective grinding of teeth as a treatment
to treat pain in temporomandibular joint?
Fig. 19 Who would you consult when a patient presents to you with a temporomandibular joint
abnormality?
Fig. 20 Do you feel that understanding the function and dysfunction of temporomandibular
joint is necessary to a dentist?
Fig. 21 Percentage of correct answers for each question
Discussion
Being the most common cause of orofacial pain,[2] importance of TMJ and its disorders must be stressed at the undergraduate level.
The present study was conducted to analyze the knowledge of students undergoing their
undergraduate residency program regarding their fundamental understanding of TMJ and
its disorders. Results of studies[3]
[4]
[5] conclude that the knowledge and attitude of dentists toward treating a TMD is undesirable.
The present study included a total of 110 students who completed the questionnaire
regarding different aspects of TMJ disorders.
In this study, knowledge-based awareness about different aspects of TMJ was analyzed
by distributing questionnaire with questions pertaining to different sections of anatomy,
physiology, pathology, diagnosis, treatment plan, and attitude.[1]
[6]
[7] Correct response of each question was calculated in percentage. The percentages
were further subgrouped under different sections of questions.
Out of 110 study participants, only 73 students (66.3%) answered correctly that TMJ
is made up of 3 bones comprising of the condylar head, glenoid fossa of the temporal
bone, and articular disc that is regarded as nonossified bone, while 37 answered that
it is made up of 2 bones.
Eighty-four (76.3%) of total students answered correctly that the articular disc is
an avascular tissue made up of fibrous connective tissue, while the remaining 26 answered
that it is made up of blood vessels, nerves, and fibrous connective tissue.
Medial and lateral pterygoid are two of the muscles of mastication, to this 66 (60%)
of the total students answered correctly, while 20 of them answered to be medial pterygoid,
17 of them answered to be lateral pterygoid, and 7 of them answered it to be buccinator.
Accessory ligaments of the TMJ are stylomandibular and sphenomandibular ligament,
to this 86 (78.1%) of the total students answered correctly, while 6 answered that
it is the temporomandibular ligament, 8 answered it to be the capsular ligament, and
10 answered that it is both stylomandibular and temporomandibular ligament.
Ligaments of the TMJ passively restrain the movement and only 56 (50.9%) of them answered
correctly. Fifty students answered that the ligaments function by actively restraining
the movement of the joint while 4 of them said that it allows for complete rotation
of the condyle.
Condyle articulates with the intermediate zone of the articular disc, to this 72 (65.4%)
of the students answered correctly, while 30 students answered that the condyle articulates
with the mandibular fossa and 8 with the posterior zone of the articular disc.
TMJ movement is seen as both rotatory and translatory motion, to this 88 (80%) students
answered correctly while 8 believed that the movement is only rotation around the
axis and 14 believed that the movement is only as translation along the articular
eminence.
Closing of the mouth is aided by the elevator muscles. Both the temporalis muscle
and medial pterygoid muscle are elevator muscles and 28 (25.4%) answered correctly.
Thirty-four believed that only the temporalis muscle functions to close the mouth,
while 40 answered it to be only medial pterygoid. Eight of the total students answered
it to be lateral pterygoid muscle.
Opening of the mouth is aided by the depressor muscles. Both the lateral pterygoid
muscle and suprahyoid muscles form the depressors and only 14 (12.7%) of the total
students answered correctly. Eighty of the total students believed that only lateral
pterygoid functions to open the mouth, while 16 of them answered it to be the medial
pterygoid muscle.
Disorders of the TMJ encompass the muscles, ligaments, temporal bone, condyle, and
articular disc. To this 38 (34.5%) answered correctly that the joint disorder does
not pertain only to the temporal bone, condyle, and the articular disc, while 36 believed
that it is true. Thirty students were not sure while 6 students did not know.
Thirty-two (29%) students correctly answered that TMJ disorder can be presented with
restricted mouth opening, pain at the region of teeth, and temple, while the remaining
78 believed that it only presented with restricted opening of the mouth.
Restricted mouth opening can be due to both reasons of spasm of the muscles and locking
of the articular disc. Forty-four (40%) answered correctly, 44 believed it to be muscle
spasm, and 16 believed locking of the articular disc restricts the opening of mouth.
Six answered that lengthening of the muscle can restrict opening of mouth.
Acute pain following a cavity restoration near the angle of the mandible is a muscular
disorder. To this 26 (23.6%) answered correctly with extracapsular disorder, while
64 believed it is due to both extracapsular disorder and intracapsular disorder and
20 believed it is due to intracapsular disorder.
A click sound is an indication of displacement of the articular disc which comes under
intracapsular disorders. Twenty-nine (26.3%) students answered correctly, while 67
students believed that it is both intracapsular and extracapsular disorder and 14
students believed that it is an extracapsular disorder.
Magnetic resonance imaging is the gold standard for the diagnosis of TMJ disorder,
to this 23 (20.9%) of the total students answered correctly. Note that 47, 28, and
12 students believed that radiologic examination of TMJ is best viewed in cone beam
computed tomography, computed tomography, and orthopantomogram, respectively.
Disorders of the TMJ can be treated with counseling, occlusal splint, and hot fomentation.
Only 10 (9%) of the total students answered correctly, while 54, 34, and 12 of the
total students believed that only hot fomentation, counseling, and occlusal splint,
respectively, treat TMJ disorder.
Restoration of a single tooth in a complete dentate patient must always be done in
maximum intercuspation. Only 25 (22.7%) of the total students answered correctly,
while 42 believed it should be done in centric relation and 43 did not know.
Selective grinding should be done in centric relation. Thirty-three (30%) of the total
students answered correctly, while 31 believed that it should be done in maximum intercuspa-tion
and 46 students did not know what is selective grinding.
Both prosthodontists and oral and maxillofacial surgeons play a vital role in the
treatment of TMJ. Fifty-two (47.2%) answered correctly, while 32 and 26 believed that
prosthodontists alone or oral and maxillofacial surgeons alone, respectively, treat
an abnormality of TMJ.
All students answered that the understanding of function and dysfunction of the TMJ
is necessary for a dentist.
The level of awareness decreased as we progressed from the first to last section.
The highest percentage of awareness was calculated in the section of anatomy followed
by physiology. The mean calculated percentage of sections of pathology, diagnosis,
and treatment planning were below 50% indicating that less than half of the study
participants were not aware of these aspects, thus proving the lack of knowledge in
these aspects.
This shows that there is an awareness about the basic understanding of the TMJ; however,
to be able to clinically apply the knowledge and diagnose a disorder of TMJ, more
than half of the participants were unacquainted of it. This indicates the lack of
practical knowledge and clinical translation of knowledge among the undergraduate
students. This is in accordance to a study conducted by Alhussini et al.[3]
In the present study, 100% of the students realized the importance of TMJ for a dentist.
Treatment planning of TMJ is an interdisciplinary approach between a prosthodontist
and an oral and maxillofacial surgeon. However, when confronted with a patient with
TMJ disorder, the general dental practitioner must be able to differentiate it from
the other causes of orofacial pain and be able to diagnose the type of disorder and
also be able to educate the patient and counsel them regarding the physical therapeutic
modalities and further refer them to a specialist.
However, from the present study, it can be inferred that the curriculum of the undergraduate
level does not stress on covering all the aspects related to TMJ and hence its importance
must be stressed.
