Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

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Dr Mohan Z Mani

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On Sep 2018




Prof. Somashekhar Nimbalkar

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Prof. Somashekhar Nimbalkar
Head, Department of Pediatrics, Pramukhswami Medical College, Karamsad
Chairman, Research Group, Charutar Arogya Mandal, Karamsad
National Joint Coordinator - Advanced IAP NNF NRP Program
Ex-Member, Governing Body, National Neonatology Forum, New Delhi
Ex-President - National Neonatology Forum Gujarat State Chapter
Department of Pediatrics, Pramukhswami Medical College, Karamsad, Anand, Gujarat.
On Sep 2018




Dr. Kalyani R

"Journal of Clinical and Diagnostic Research is at present a well-known Indian originated scientific journal which started with a humble beginning. I have been associated with this journal since many years. I appreciate the Editor, Dr. Hemant Jain, for his constant effort in bringing up this journal to the present status right from the scratch. The journal is multidisciplinary. It encourages in publishing the scientific articles from postgraduates and also the beginners who start their career. At the same time the journal also caters for the high quality articles from specialty and super-specialty researchers. Hence it provides a platform for the scientist and researchers to publish. The other aspect of it is, the readers get the information regarding the most recent developments in science which can be used for teaching, research, treating patients and to some extent take preventive measures against certain diseases. The journal is contributing immensely to the society at national and international level."



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Sri Devaraj Urs Medical College
Sri Devaraj Urs Academy of Higher Education and Research , Kolar, Karnataka
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Dr. Saumya Navit

"As a peer-reviewed journal, the Journal of Clinical and Diagnostic Research provides an opportunity to researchers, scientists and budding professionals to explore the developments in the field of medicine and dentistry and their varied specialities, thus extending our view on biological diversities of living species in relation to medicine.
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Dr Saumya Navit
Professor and Head
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Saraswati Dental College
Lucknow
On Sep 2018




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Dr. Arunava Biswas
MD, DM (Clinical Pharmacology)
Assistant Professor
Department of Pharmacology
Calcutta National Medical College & Hospital , Kolkata




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Best regards,
C.S. Ramesh Babu,
Associate Professor of Anatomy,
Muzaffarnagar Medical College,
Muzaffarnagar.
On Aug 2018




Dr. Arundhathi. S
"Journal of Clinical and Diagnostic Research (JCDR) is a reputed peer reviewed journal and is constantly involved in publishing high quality research articles related to medicine. Its been a great pleasure to be associated with this esteemed journal as a reviewer and as an author for a couple of years. The editorial board consists of many dedicated and reputed experts as its members and they are doing an appreciable work in guiding budding researchers. JCDR is doing a commendable job in scientific research by promoting excellent quality research & review articles and case reports & series. The reviewers provide appropriate suggestions that improve the quality of articles. I strongly recommend my fraternity to encourage JCDR by contributing their valuable research work in this widely accepted, user friendly journal. I hope my collaboration with JCDR will continue for a long time".



Dr. Arundhathi. S
MBBS, MD (Pathology),
Sanjay Gandhi institute of trauma and orthopedics,
Bengaluru.
On Aug 2018




Dr. Mamta Gupta,
"It gives me great pleasure to be associated with JCDR, since last 2-3 years. Since then I have authored, co-authored and reviewed about 25 articles in JCDR. I thank JCDR for giving me an opportunity to improve my own skills as an author and a reviewer.
It 's a multispecialty journal, publishing high quality articles. It gives a platform to the authors to publish their research work which can be available for everyone across the globe to read. The best thing about JCDR is that the full articles of all medical specialties are available as pdf/html for reading free of cost or without institutional subscription, which is not there for other journals. For those who have problem in writing manuscript or do statistical work, JCDR comes for their rescue.
The journal has a monthly publication and the articles are published quite fast. In time compared to other journals. The on-line first publication is also a great advantage and facility to review one's own articles before going to print. The response to any query and permission if required, is quite fast; this is quite commendable. I have a very good experience about seeking quick permission for quoting a photograph (Fig.) from a JCDR article for my chapter authored in an E book. I never thought it would be so easy. No hassles.
Reviewing articles is no less a pain staking process and requires in depth perception, knowledge about the topic for review. It requires time and concentration, yet I enjoy doing it. The JCDR website especially for the reviewers is quite user friendly. My suggestions for improving the journal is, more strict review process, so that only high quality articles are published. I find a a good number of articles in Obst. Gynae, hence, a new journal for this specialty titled JCDR-OG can be started. May be a bimonthly or quarterly publication to begin with. Only selected articles should find a place in it.
An yearly reward for the best article authored can also incentivize the authors. Though the process of finding the best article will be not be very easy. I do not know how reviewing process can be improved. If an article is being reviewed by two reviewers, then opinion of one can be communicated to the other or the final opinion of the editor can be communicated to the reviewer if requested for. This will help one’s reviewing skills.
My best wishes to Dr. Hemant Jain and all the editorial staff of JCDR for their untiring efforts to bring out this journal. I strongly recommend medical fraternity to publish their valuable research work in this esteemed journal, JCDR".



Dr. Mamta Gupta
Consultant
(Ex HOD Obs &Gynae, Hindu Rao Hospital and associated NDMC Medical College, Delhi)
Aug 2018




Dr. Rajendra Kumar Ghritlaharey

"I wish to thank Dr. Hemant Jain, Editor-in-Chief Journal of Clinical and Diagnostic Research (JCDR), for asking me to write up few words.
Writing is the representation of language in a textual medium i e; into the words and sentences on paper. Quality medical manuscript writing in particular, demands not only a high-quality research, but also requires accurate and concise communication of findings and conclusions, with adherence to particular journal guidelines. In medical field whether working in teaching, private, or in corporate institution, everyone wants to excel in his / her own field and get recognised by making manuscripts publication.


Authors are the souls of any journal, and deserve much respect. To publish a journal manuscripts are needed from authors. Authors have a great responsibility for producing facts of their work in terms of number and results truthfully and an individual honesty is expected from authors in this regards. Both ways its true "No authors-No manuscripts-No journals" and "No journals–No manuscripts–No authors". Reviewing a manuscript is also a very responsible and important task of any peer-reviewed journal and to be taken seriously. It needs knowledge on the subject, sincerity, honesty and determination. Although the process of reviewing a manuscript is a time consuming task butit is expected to give one's best remarks within the time frame of the journal.
Salient features of the JCDR: It is a biomedical, multidisciplinary (including all medical and dental specialities), e-journal, with wide scope and extensive author support. At the same time, a free text of manuscript is available in HTML and PDF format. There is fast growing authorship and readership with JCDR as this can be judged by the number of articles published in it i e; in Feb 2007 of its first issue, it contained 5 articles only, and now in its recent volume published in April 2011, it contained 67 manuscripts. This e-journal is fulfilling the commitments and objectives sincerely, (as stated by Editor-in-chief in his preface to first edition) i e; to encourage physicians through the internet, especially from the developing countries who witness a spectrum of disease and acquire a wealth of knowledge to publish their experiences to benefit the medical community in patients care. I also feel that many of us have work of substance, newer ideas, adequate clinical materials but poor in medical writing and hesitation to submit the work and need help. JCDR provides authors help in this regards.
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Indexation and online availability: Indexation transforms the journal in some sense from its local ownership to the worldwide professional community and to the public.JCDR is indexed with Embase & EMbiology, Google Scholar, Index Copernicus, Chemical Abstracts Service, Journal seek Database, Indian Science Abstracts, to name few of them. Manuscriptspublished in JCDR are available on major search engines ie; google, yahoo, msn.
In the era of fast growing newer technologies, and in computer and internet friendly environment the manuscripts preparation, submission, review, revision, etc and all can be done and checked with a click from all corer of the world, at any time. Of course there is always a scope for improvement in every field and none is perfect. To progress, one needs to identify the areas of one's weakness and to strengthen them.
It is well said that "happy beginning is half done" and it fits perfectly with JCDR. It has grown considerably and I feel it has already grown up from its infancy to adolescence, achieving the status of standard online e-journal form Indian continent since its inception in Feb 2007. This had been made possible due to the efforts and the hard work put in it. The way the JCDR is improving with every new volume, with good quality original manuscripts, makes it a quality journal for readers. I must thank and congratulate Dr Hemant Jain, Editor-in-Chief JCDR and his team for their sincere efforts, dedication, and determination for making JCDR a fast growing journal.
Every one of us: authors, reviewers, editors, and publisher are responsible for enhancing the stature of the journal. I wish for a great success for JCDR."



Thanking you
With sincere regards
Dr. Rajendra Kumar Ghritlaharey, M.S., M. Ch., FAIS
Associate Professor,
Department of Paediatric Surgery, Gandhi Medical College & Associated
Kamla Nehru & Hamidia Hospitals Bhopal, Madhya Pradesh 462 001 (India)
E-mail: drrajendrak1@rediffmail.com
On May 11,2011




Dr. Shankar P.R.

"On looking back through my Gmail archives after being requested by the journal to write a short editorial about my experiences of publishing with the Journal of Clinical and Diagnostic Research (JCDR), I came across an e-mail from Dr. Hemant Jain, Editor, in March 2007, which introduced the new electronic journal. The main features of the journal which were outlined in the e-mail were extensive author support, cash rewards, the peer review process, and other salient features of the journal.
Over a span of over four years, we (I and my colleagues) have published around 25 articles in the journal. In this editorial, I plan to briefly discuss my experiences of publishing with JCDR and the strengths of the journal and to finally address the areas for improvement.
My experiences of publishing with JCDR: Overall, my experiences of publishing withJCDR have been positive. The best point about the journal is that it responds to queries from the author. This may seem to be simple and not too much to ask for, but unfortunately, many journals in the subcontinent and from many developing countries do not respond or they respond with a long delay to the queries from the authors 1. The reasons could be many, including lack of optimal secretarial and other support. Another problem with many journals is the slowness of the review process. Editorial processing and peer review can take anywhere between a year to two years with some journals. Also, some journals do not keep the contributors informed about the progress of the review process. Due to the long review process, the articles can lose their relevance and topicality. A major benefit with JCDR is the timeliness and promptness of its response. In Dr Jain's e-mail which was sent to me in 2007, before the introduction of the Pre-publishing system, he had stated that he had received my submission and that he would get back to me within seven days and he did!
Most of the manuscripts are published within 3 to 4 months of their submission if they are found to be suitable after the review process. JCDR is published bimonthly and the accepted articles were usually published in the next issue. Recently, due to the increased volume of the submissions, the review process has become slower and it ?? Section can take from 4 to 6 months for the articles to be reviewed. The journal has an extensive author support system and it has recently introduced a paid expedited review process. The journal also mentions the average time for processing the manuscript under different submission systems - regular submission and expedited review.
Strengths of the journal: The journal has an online first facility in which the accepted manuscripts may be published on the website before being included in a regular issue of the journal. This cuts down the time between their acceptance and the publication. The journal is indexed in many databases, though not in PubMed. The editorial board should now take steps to index the journal in PubMed. The journal has a system of notifying readers through e-mail when a new issue is released. Also, the articles are available in both the HTML and the PDF formats. I especially like the new and colorful page format of the journal. Also, the access statistics of the articles are available. The prepublication and the manuscript tracking system are also helpful for the authors.
Areas for improvement: In certain cases, I felt that the peer review process of the manuscripts was not up to international standards and that it should be strengthened. Also, the number of manuscripts in an issue is high and it may be difficult for readers to go through all of them. The journal can consider tightening of the peer review process and increasing the quality standards for the acceptance of the manuscripts. I faced occasional problems with the online manuscript submission (Pre-publishing) system, which have to be addressed.
Overall, the publishing process with JCDR has been smooth, quick and relatively hassle free and I can recommend other authors to consider the journal as an outlet for their work."



Dr. P. Ravi Shankar
KIST Medical College, P.O. Box 14142, Kathmandu, Nepal.
E-mail: ravi.dr.shankar@gmail.com
On April 2011
Anuradha

Dear team JCDR, I would like to thank you for the very professional and polite service provided by everyone at JCDR. While i have been in the field of writing and editing for sometime, this has been my first attempt in publishing a scientific paper.Thank you for hand-holding me through the process.


Dr. Anuradha
E-mail: anuradha2nittur@gmail.com
On Jan 2020

Important Notice

Original article / research
Year : 2021 | Month : August | Volume : 15 | Issue : 8 | Page : ZC17 - ZC22 Full Version

A Morphometric Analysis of Intra-articular Disc of Temporomandibular Joints in Cadavers


Published: August 1, 2021 | DOI: https://doi.org/10.7860/JCDR/2021/45438.15224
Pratik Ashokkumar Agrawal, Navin S Shah, Ramnarayan A Gandotra, Karan Vasantray Panchal, Rishabh Navin Shah

1. Postgraduate Student, Department of Oral and Maxillofacial Surgery, K. M. Shah Dental College and Hospital, Vadodara, Gujarat, India. 2. Head, Department of Oral and Maxillofacial Surgery, K.M. Shah Dental College and Hospital, Vadodara, Gujarat, India. 3. Head, Department of Anatomy, S.B.K.S Medical Institute and Research Centre, Vadodara, Gujarat, India. 4. Postgraduate Student, Department of Oral and Maxillofacial Surgery, K. M. Shah Dental College and Hospital, Vadodara, Gujarat, India. 5. Senior Lecturer, Department of Oral and Maxillofacial Surgery, K.M. Shah Dental College and Hospital, Vadodara, Gujarat, India.

Correspondence Address :
Dr. Navin S Shah,
B-101, Prakruti Annexe, Jain Nagar, Paldi, Ahmedabad-380007, Gujarat, India.
E-mail: drnavin33@yahoo.com

Abstract

Introduction: Temporomandibular Joint (TMJ) has been a controversial topic in Oral and Maxillofacial Surgery speciality especially regarding temporomandibular joint disorders and internal derangement of articular disc. The aetiology behind it has been related to the anatomic variations of the disc and its impact on the functioning of the articular disc. To understand such anatomic variation, the study has been conducted that will help future maxillofacial surgeon’s in designing accurate prosthetic articular disc that will improve the overall mechanics of the functioning of the prosthetic disc.

Aim: To analyse the morphometric variations of the intra-articular disc in terms of circumference of the disc, perforations and their thickness within the disc in cadavers.

Materials and Methods: The present observational study was carried out on cadavers in the Department of Anatomy. SBKS Medical College and Research Centre, Sumandeep Vidyapeeth University, Gujarat, India. The study was done from January 2017 to October 2018. Temporomandibular joints were dissected bilaterally from 10 human cadavers, i.e., 20 articular discs. The disc was removed and was measured with the help of thread, vernier callipers and standardised metallic scale and the circumference and thickness in the disc were evaluated. Descriptive statistical test was used and Chi-square test was applied.

Results: Mean thickness of disc, both in males as well as females ranged from 1.4-2.0 mm in the Posterio-Medial (PM) and Posterio-Lateral (PL) region, while in Anterio-Medial (AM) and Anterio-Lateral (AL) region it ranged from 1.6-1.8 mm. Maximum length of disc ranged from 12-13 mm in anterio-posterio dimension while in Medio-Lateral (ML) it was 22-23 mm.

Conclusion: The study gives an indepth knowledge about the various morphometric variations of articular disc and also shows its impact on the functioning of the disc. The study also directs maxillofacial surgeons to design prosthetic articular disc with greater accuracy and anatomical knowledge so that the procedures like surgical replacement of the disc can be carried out with greater potency and efficacy for the betterment of the patient.

Keywords

Articular surface variations, Bilateral diarthroidial joint, Perforations, Thinning of disc

Temporomandibular Joint (TMJ) is a multiplex, bilateral diarthroidial, ginglymoarthroidal, synovial or a compound joint acquiring the anatomical position between the squamous part of temporal bone and the head of the mandibular condyle. TMJ is quite superficial and it lies below the posterior end of the zygomatic arch just anterior of the external acoustic meatus. It is unique because it’s both articular surfaces are non congruent and non co-extensive; hence there is the presence of intra-articular disc (1),(2),(3).

The articular disc appears to be the posterior extension of the lateral pterygoid muscle. As viewed from the sagittal direction the articular disc can be observed in 3 distinct zones according to the thickness. Rees JC in 1954 suggested that the central most regions is the thinnest zone and is known as the intermediate zone of about 1 mm in thickness, the anterior part which is considerably thick of about 2 mm and the posterior band of the disc which is the thickest of all of about 3mm in thickness (4),(5),(6).

The synovial joint is enclosed in a thin sleeve of fibrous tissue which blends the periosteum of the mandible and envelops the articular disc and is known as the temporomandibular joint capsule or the capsular ligament. The capsule defines the anatomical and functional boundaries of the TMJ (7),(8),(9),(10),(11). Usually the disk is displaced anteriorly, and frequently there is an associated perforation of the posterior attachment of the disk (12). There are no proved aetiologic factors for internal derangements of the temporomandibular joint. Proposed aetiologic factors include jaw trauma, muscle hyperactivity, hyperextension of the mandible, missing posterior teeth, and occlusal discrepancies (13),(14),(15),(18).

There has also been limited data about the anterior and posterior attachments of the disc about how the attachments vary between lateral, central and medial regions of the joint (19). The relationship between disc surface irregularities and disc displacement may not be as simple as previously thought and further studies are needed to fully understand the relationship between remodelling, disc displacement, and degenerative changes (20),(21),(22),(23),(24). Therefore the need of this study is to establish a baseline data regarding the exact morphometric anatomy of the intra-articular disc of temporomandibular joint which is unavailable in the present literatures regarding the anatomy of articular disc so that with the help of this data more treatment options will be available to the surgeons such as surgical replacement of the disc can be made possible by knowing the accurate anatomy of the disc giving the patients more accurate functioning of the prosthetic disc (25),(26),(27).

The aim of the study was to analyse the morphometric variations of the disc, in terms of thickness, circumference, dimensions and perforation in the disc in human cadavers. The objectives of the study were:

1) To establish the baseline data regarding the thickness in anterior, posterior, medio-lateral and central part of the disc.
2) To evaluate the stress bearing areas of the disc.
3) To evaluate the dimensions of the disc in anterio-posterior and medio-lateral diameters.
4) To evaluate the perforations of the disc in anterior, posterior and central part of the disc.
5) To evaluate the anatomical variations in left and right articular disc of the same individual cadaver.
6) To evaluate the anatomical variations of the articular disc amongst male and female cadavers.
7) To evaluate the circumference of the disc.

Material and Methods

This observational study was carried out in the Department of Anatomy, SBKS Medical College and Research Centre, Sumandeep Vidyapeeth University, Gujarat, India, from January 2017 to October 2018.

Sample size calculation: A sample size of 10 was achieved by the following formula

n=z2×σ2/MOE2
n: sample size
z: found by using a z-score table
σ: population standard deviation
MOE: Margin of Error

‘n’ without correction equals the quantity 0.66 squared times 23 squared all over 5 squared, and rounded upto the nearest whole number. =9.217, which rounds upto 10. With a margin of error of ±5% and a population standard deviation of 23, the sample size would need to be 10.

Temporomandibular joints were dissected bilaterally in 10 human cadavers available in the Department of Anatomy. The details of the cadaveric subjects are given under (Table/Fig 1).

Statement of human and animal rights: The Human Cadaveric dissection was carried out after the approvals granted by the Institutional Ethics Committee bearing referenced number as SVIEC/DENT/ON/BNPG16/D17009 and also from the Head of the Department of Anatomy. The dissections were carried out according to the ethical standards of the committee.

Dissection Steps (27)

Preauricular incision and approach

Step 1: Preauricular incision was made through the skin and subcutaneous tissue upto the superficial temporal fascia. Dissection was carried out above the zygomatic arch to the level of the superficial layer of the temporalis fascia. After that the dissection proceeds abruptly below the zygomatic arch, along the external auditory meatus (Table/Fig 2).

Step 2: An Oblique incision was made through the superficial layer of the temporalis fascia.

Step 3: With the help of a periosteal elevator periosteum of the arch was stripped off and dissection was done superficial to capular ligament of TMJ.

Step 4: An upright incision was made through the prevailing tissues in front of the external auditory meatus upto the periosteal elevator.

Step 5: The tissues were stretched apart and the temporomandibular joint capsule was encountered.

Step 6: The capsule was cut laterally, exposing the superior compartment of the disc. After that the cut was made medially and posteriorly till the glenoid (mandibular) fossa was been exposed (28),(29).

Step 7: The disc and the condylar neck were separated from the muscles by making an additional incision through the two head of the lateral pterygoid muscles. The actual incision was continued posterio-medially through the attachments of the capsular ligament of TMJ meeting the anterior incision, freeing the condyle and the discs shown in (Table/Fig 3) (30),(31).

Step 8: The condyle and adjoining neck, including the Pterygoid fossa (fovea) was separated as a unit from the remainder of the mandible with an oscillating saw.

Boundaries of articular disc

Superiorly: The corresponding joint space and limitation by the glenoid fossa of the temporal bone.

Inferiorly: The mandibular condyle.

Anteriorly: The disc was continuous with the anterior capsular ligaments, superior and inferior lateral pterygoid muscle fibres.

Posteriorly: The disc was continuous with loose connective tissue.

Laterally and medially: Established upto the lateral and medial condylar poles.

Separation of disc from condyle (31)

Step 1: An incision was made horizontally through the bilaminar area just behind the posterior part of disc, thus opening the inferior compartment.

Step 2: It was continued to the lateral and medial poles, where the disc is most tightly adhered. The disc was then separated from the condylar poles and the incision was continued anteriorly.

Step 3: Here with sharp scalpel dissection, the anterior extension of the disc was separated from the condyle and the fibres of the lateral Pterygoid.

After that, certain morphometric parameters were decided as given in (Table/Fig 4) and also explained through diagrammatic representation as in (Table/Fig 5).

Definitions of the morphometric parameters (32)

1. Anterior-Posterior (AP) Length: Defined as the maximum length drawn from the point A to point P of the articular disc.
2. Medio-lateral (ML) length: Defined as the maximum length drawn from point M to point L of the articular disc.
3. After that we get a Point C of the disc or the Central point (C) region of the disc which is defined as the point obtained on dividing the disc into anterio-posterior and medio-lateral dimensions of the disc.
4. After that the disc was divided into four regions as Posterio-Medial (PM): defined as the part obtained by joining of the posterior, medial and central points of the disc.
5. Posterio-Lateral (PL): Defined as the part obtained by joining the posterior, lateral and central points of the disc.
6. Anterio-Lateral (AL): defined as the part obtained by joining the anterior, lateral and central points of the disc
7. Anterio-Medial (AM): Defined as the part obtained by joining the anterior, medial and central points of the disc.

After the appropriate division of the disc, the measuring of the disc was carried out by the primary investigator with the help of Aerospace Stainless Steel 8 inch/200 mm digital vernier calipers (manufacturer: Kovea Co., Ltd.,) for the thickness of the disc in all the five divisions namely PM, PL, AM, AL and central part of the disc. The examiner was calibrated based on the inter-examiner reliability method. The inter-examiner reliability score was 7 (interpreted as very good according to Regier et al.,). The dimensions (i.e., maximum length) in anterio-posterior and medio-lateral aspects and the circumference of the disc were measured with the help of a thread and standardised metallic scale. The perforations in the disc were evaluated on the basis of location, shape, size and number (33).

Statistical Analysis

Descriptive Statistically Method Applied: Two sample t-test Method. The software used for calculating is IBM Statistical Package for the Social Sciences (SPSS) Statistics.

Formula

Pooled Standard Deviation (r)=v{(n1-1) σ12+(n2-1) σ22/(n1+n2-2)}
Standard Error (S)=R×v(1/n1)+(1/n2)
T-Statistic=μ1-μ2/S
Where,
μ1=Mean1
σ1=Standard Deviation1
n1=Sample Size1
μ2=Mean2
σ2=Standard deviation2
n2=Sample size2

Results

In present study, authors have collected data of total 10 cadavers bilaterally or 20 temporomandibular joints and articular disc and out of them 80.00% were male whereas 20.00% were female, in the age range of 55-65 years.

Circumference of the disc: The observed range of circumference of the disc in males was in the range of 67-75 mm while that in females was 68-70 mm. The mean average in males was in the range was 71-72 mm while that in females was 69 mm (Table/Fig 6).

Thickness of the disc: The mean average thickness of the disc in the PM region in males was 1.4 mm on left side while on right side it was 1.5 mm. In females, it was 2.0 mm on both the sides. Similarly the mean average thickness of the disc in the PL region in males on left side was 1.5 mm and 1.6 mm on right side. While in females, it was 1.5 mm on both the sides.

The mean average thickness of the disc in the AL region of the disc in males on left side was 1.7 mm and 1.6 mm on right side while in females was 1.0 on left side and 1.5 mm on the right side. In the AM region it was 1.8 mm on the left side and 1.7 mm on the right side in males while that in females was 1.0 mm on both the sides. At the Central portion of the disc the thickness was in the range of 3.3-3.5 mm in both males and females on left and right side (Table/Fig 7).

Dimensions of the disc: The mean average dimension of the disc in the Anterio-posterior direction in males was 12.875-13.75 mm while in females was 13.0-13.5 mm.The chi-square statistic is 0.0182. The p-value is 0.892757. The result is not significant at p-value <0.05. Similarly the Medio-lateral dimension in males was 22.0-23.62 mm while in females was 22-23 mm (Table/Fig 8).

Perforations in the disc: In 1(10%) of the male, partially dentulous cadaver, aged about 57 years, perforation of disc was evident. On the left side the perforation is evident on the PL aspect and on the right side; perforation is evident on the PM aspect. The dimension of the perforation was 2.0×3.0 mm on the left side and 2.0×2.0 mm on the right side of the disc respectively. The shape of the perforation of the left is oval in shape while that on the right side is round in shape (Table/Fig 9).

Irregular surfaces in the disc were observed in almost 16 temporomandibular joint discs and that too mostly in PM aspects. Flattening of the condylar surfaces was observed on the right and left side of another temporomandibular joint of same cadaver (Table/Fig 10).

Posteriorly on the medial and lateral aspects, thinning of the disc was observed in the majority (90%) of non perforated discs, more often in partially dentulous males cadavers indicating a possible continuous activity leading to eventual thinning of the disc and which may lead to perforations in the near future (Table/Fig 11).

Discussion

The temporomandibular joint in particular the Intra-articular disc has always been a focal point of clinical controversy, theory, research and surgery (34). In the present study, it was observed that in males, there was reduction in the mean thickness of the articular disc in the posterior segment whether PM, PL right or left side which ranged from 1.5 mm-1.6 mm. Also, it was observed that in males the mean thickness of articular disc in the anterior segment whether AM; AL right or left side there was an increase in the thickness which ranged from 1.6-1.8 mm. This shows that the load transfer much have been much greater on the posterior aspect than that on the anterior aspect of the disc. Thus, the contact between the mandible and the cranium must have been concentrated, resulting in the damage on the posterior segment of the disc. This could have increased stress and strain on the posterior segment and could have led to thinning of the disc and eventually in perforation of the disc.

It was also observed that the mean of maximum length of articular disc in both males and females ranges from 12-13 mm in Anterio-posterior dimension and 22-23 mm in medio-lateral dimension. According to the present data, perforation of the disc most frequently occurred in the PM and PL part of the articular disc, and as per the available literature if the morphology of the disc is altered the discal ligaments get elongated and the disc slides or translates along the articular surface of the condyle. This type of movement is not present in the healthy joint. The degree of elongation is determined by the anatomy of the disc. Alteration in the morphology of the disc can change the normal functioning relationship.

In the resting closed joint position, the inter-articular pressure is low. The disc moves freely if the ligaments are elongated. In the closed joint position the disc will move into a more forward location, which will be resisited by the discal ligaments and posterior part of the disc (35). Due to more pulling of the muscle, the posterior border of disc becomes more thinned and so the disc is displaced in more anterio-medial direction (36).

The superior retrodiscal lamina provides little resistance in the closed joint position; the medial and anterior positions of the disc are maintained. As the posterior border of the disc becomes thinned, it can be displaced further into the discal space so that the condyle becomes positioned on the posterior border of the disc. This condition is known as ‘functional disc displacement’ (37),(38).

Irregular surfaces were also observed. Remodelling of the disc has usually been associated with thinning, whereas perforation has been considered a sign of degenerative change (39).

Another important fact that was observed in the present study was the shape of the condyle. Flat type of condylar surface was seen in the right and left side of the same individual having perforations in the disc. Flat type of condylar surfaces usually indicates the abnormal anatomic variation in the morphology of the condyle which can lead to erosion of the condylar surfaces eventually resulting into temporomandibular joint osteoarthritis.

In this present study, predisposing symptoms that could lead to temporomandibular joint disorders and internal derangement like thinning of the disc, perforation of the disc, irregular surfaces on the posterior aspect of the disc have been reported and this anatomical variation have been observed in the elderly people. Due to lack of dentition stress and strain gets increased on a particular segment of the disc resulting in thinning of the disc over a gradual period of time eventually resulting in perforation of the disc, if not been given timely treatment. As per the available literature (39) the signs and symptoms of arthrosis which include degenerative changes in the articular surfaces and perforations of the disc are usually seen in the elderly age group people than the younger group. Perforations are in a more advanced stage in the older group. Not only the frequency of degenerative changes but also their severity increases with age.

From the above discussed observations, its clinical implications and along with the literature that is being available (39), it can be suggested that the data which authors observed from the present study was more in relevance to the signs and symptoms of temporomandibular joint dysfunction and internal derangement that could have been already established or would probably be seen in the near future.

To prevent such type of temporomandibular joint dysfunction and internal derangement clinician should always look for the early signs and symptoms of it and should educate, motivate and explain the severity and consequences of such disorders to the patient so that their treatment could be initiated at an early stage for the betterment of the patient. Much literature has outlined the anatomy of the disc in relation to its thickness and maximum length of the disc in anterio-posterior and medio-lateral dimension (40). This is the first kind of study that has also focused on the circumference of the disc. By knowing the circumference of the disc, the anatomy of the disc becomes more accurate and one can fabricate a prosthetic articular disc in a more precise way for the betterment of the patient.

Limitation(s)

The cadavers available in the Department of Anatomy were in the range of 55 to 65 years; hence all the age group populations cannot be covered. Due to unavailability of the female cadavers, equal amount of male and female cadavers could not be analysed. The study does not include completely edentulous cadavers which could have shown more anatomical variations in the disc due to prolonged forces deviated towards the articular disc and condylar surfaces. Cone-Beam Computed Tomography Systems (CBCT), 3D CT scan or an MRI could have been used to compare the results with the physical measurements of the disc which could have gained more precise morphometric anatomic measurements of the disc.

Conclusion

From the present study, it can be concluded that excessive stress on a particular portion of the disc leads to thinning of the disc and ultimately leading to perforation in that area. A newer morphometric dimension that is the circumference of the articular disc was measured. By knowing the circumference of the articular disc replica of the articular disc can be accurately developed which is biocompatible to the human beings and surgeries like total articular disc replacement can be carried out with much ease which would be similar to knee arthroplasty procedures.

In conclusion, the study gives a greater knowledge about the complete morphometric anatomy of the articular disc that will guide maxillofacial surgeons and other research workers in accurately knowing the morphometric dimensions of the articular disc of temporomandibular joints so that they can replicate exact prosthetic articular disc. By addressing to the problems of temporomandibular joint at an early stage and diagnosing the abnormality of the temporomandibular joint the clinician can educate, motivate and cure the patient who requires surgical intervention in relation to the replacement of the articular disc by knowing the appropriate morphometric anatomy of the articular disc.

Acknowledgement

Authors wish to acknowledge the immense support and help received from the clerical staff of the Department of Anatomy, SBKS Medical Institute and Research Centre, Vadodara, Gujarat, India in the preservation and preparation of the cadavers as and when required namely Mr. Pankaj. Parikh (Clerk), Mr. Muljibhai Solanki (Modeller), Mr. Jagdish Harijan (Dissection Assistant), Mr. Fakir Gandhi (Dissection Assistant), and Mr. Devjibhai Rohit (Sweeper).

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DOI and Others

10.7860/JCDR/2021/45438.15224

Date of Submission: Jun 11, 2020
Date of Peer Review: Jul 21, 2020
Date of Acceptance: May 29, 2021
Date of Publishing: Aug 01, 2021

AUTHOR DECLARATION:
• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? No
• For any images presented appropriate consent has been obtained from the subjects. NA

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