Temporo mandibular joint

Temporo mandibular joint- public health aspects

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2. TEMPORO-MANDIBULAR JOINT 2 Presented by Dr.Akhil C A First Year PG Dept.Of Public Health Dentistry SCB Dental College,Cuttack

3. CONTENTS Introduction Anatomy of Temporomandibular joint DEVELOPMENT of temporomandibular joint Vascular supply and innervations MOVEMENTs of temporomandibular joint TMJ-CLINICAL EXAMINATION TEMPOROMANDIBULAR JOINT DISORDERS OCCLUSION AND TMJ DISORDER TMD MANAGEMENT STRATEGIES Conclusion REFERENCES 3

4. INTRODUCTION The stomatognathic system includes various anatomical structures, which allow the mouth to open, swallow, breathe, phonate , suck and perform different facial expressions. These structures are the T emporomandibular joint (TMJ), upper jaw and mandible, muscle tissues and tendons, dental arches, salivary glands, as well as the hyoid bone and the muscles that connect the latter to the scapula and the sternum, the muscles of the neck . The temporomandibular joint (TMJ), also known as the craniomandibular joint is peculiar to mammals . Pai SA, Poojari SR, Ramachandra K, Patel R, Jyothi M. Temporomandibular joint - An anatomical view. Journal of Advanced Clinical and Research Insights. 2019;6(1):1–5. 4 Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

5. A joint is defined as a  connection  between two bones in the skeletal system. Joints can be  classified  by the type of the tissue present Fibrous – bones connected by fibrous tissue. Cartilaginous – bones connected by cartilage. Synovial – articulating surfaces enclosed within fluid-filled joint capsule. Synovial joints can be  sub-classified  into several different types, depending on the shape of their articular surfaces and the movements permitted : Classification of Joints [Internet]. TeachMeAnatomy . [cited 2021Jan24]. Available from: https://teachmeanatomy.info/the-basics/joints-basic/classification-of-joints/ 5

6. Hinge  – permits movement in one plane – usually flexion and extension. E.g. elbow joint, ankle joint, knee joint. Saddle  – named due to its resemblance to a saddle on a horse’s back. It is characterised by opposing articular surfaces with a reciprocal concave-convex shape. E.g. carpometacarpal joints. Plane  – the articular surfaces are relatively flat, allowing the bones to glide over one another. E.g. acromioclavicular joint, subtalar joint. Pivot  – allows for rotation only. It is formed by a central bony pivot, which is surrounded by a bony-ligamentous ring E.g. proximal and distal radioulnar joints, atlantoaxial joint . Classification of Joints [Internet]. TeachMeAnatomy . [cited 2021Jan24]. Available from: https://teachmeanatomy.info/the-basics/joints-basic/classification-of-joints/ 6

7. Condyloid  – contains a convex surface which articulates with a concave elliptical cavity. They are also known as ellipsoid joints. E.g. wrist joint, metacarpophalangeal joint, metatarsophalangeal joint. Ball and Socket  – where the ball-shaped surface of one rounded bone fits into the cup-like depression of another bone. It permits free movement in numerous axes. E.g. hip joint, shoulder joint. Classification of Joints [Internet]. TeachMeAnatomy . [cited 2021Jan24]. Available from: https://teachmeanatomy.info/the-basics/joints-basic/classification-of-joints/ 7

8. Classification of Joints [Internet]. TeachMeAnatomy . [cited 2021Jan24]. Available from: https://teachmeanatomy.info/the-basics/joints-basic/classification-of-joints/ 8 TYPES OF SYNOVIAL JOINTS

9. The  temporomandibular joint  is a modified-hinge  type of synovial joint formed by the articulation between the squamous part of the temporal bone and the head of the mandibular condyle . 9 Pai SA, Poojari SR, Ramachandra K, Patel R, Jyothi M. Temporomandibular joint - An anatomical view. Journal of Advanced Clinical and Research Insights. 2019;6(1):1–5. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

10. The TMJ articulation consists of a mandibular or glenoid fossa, an articular eminence or tubercle, a condyle, a separating disc, a joint fibrous capsule and an extracapsular check ligament . 10 Pai SA, Poojari SR, Ramachandra K, Patel R, Jyothi M. Temporomandibular joint - An anatomical view. Journal of Advanced Clinical and Research Insights. 2019;6(1):1–5. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

11. The mandibular articulation is labelled as G inglymoarthrodial joint( ginglymus , meaning a hinge joint, allowing motion only backward and forward in one plane, and arthrodia , meaning a joint of which permits a gliding motion of the surfaces. ) Complex joint , (because it involves two separate synovial joints (right and left)) E llipsoid variety of the synovial joints similar to knee articulation. 11 Pai SA, Poojari SR, Ramachandra K, Patel R, Jyothi M. Temporomandibular joint - An anatomical view. Journal of Advanced Clinical and Research Insights. 2019;6(1):1–5. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

12. The complex movements of TMJ allow multiple functions: Chewing Sucking Swallowing Phonation Facial expressions Breathing Protrusion, retrusion , lateralization of the jaw Opening the mouth Maintain the correct pressure of the middle ear 12 Pai SA, Poojari SR, Ramachandra K, Patel R, Jyothi M. Temporomandibular joint - An anatomical view. Journal of Advanced Clinical and Research Insights. 2019;6(1):1–5.

13. Pecularities of TMJ Bilateral diarthrosis . Only joint in the human body that has a rigid end point due to closure of the teeth making occlusal contact . The surface that articulates is covered by fibrous cartilage instead of hyaline cartilage . Compared to other diarthrodial joints, TMJ develops the last (7th week [IUL]). TMJ is formed from distinct blastema . 13 Pai SA, Poojari SR, Ramachandra K, Patel R, Jyothi M. Temporomandibular joint - An anatomical view. Journal of Advanced Clinical and Research Insights. 2019;6(1):1–5.

14. ANATOMY OF TMJ Components 1. Bony components • Glenoid fossa. • Mandibular condyle • Articular eminence 2. Ligaments A . Primary • Fibrous capsule • Lateral ligament • Collateral ligament B . Accessory • Sphenomandibular ligament • Stylomandibular ligament 3. Articular disc 4. Muscles. 14 Pai SA, Poojari SR, Ramachandra K, Patel R, Jyothi M. Temporomandibular joint - An anatomical view. Journal of Advanced Clinical and Research Insights. 2019;6(1):1–5.

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16. Skeletal Components Glenoid /mandibular/articular fossae It is an elliptical concave depression, made up of squamous portion of temporal bone. They are bordered, in front, by the articular tubercles; behind they are separated from the external acoustic meatus by tympanic part of the bone. 16 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi : CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

17. Mandibular condyle This component has a tapered mandibular neck with an ovoid condylar process on it. It is 16–20 mm side to side and 9–10 mm from back to front . The head is covered with fibrocartilage and articulates with temporal bone. From the front view, there are lateral and medial projections known as poles. The lateral pole is less prominent compared to medial pole . 17 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

18. Articular eminence A convex bony prominence is present immediately anterior to the fossa known as articular eminence. It is strongly convex anteroposteriorly and somewhat concave mediolaterally . 18 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

19. Articular disc/ Meniscus The articular disc is an oval predominantly fibrous plate that divides the joint into an upper and a lower compartments . The upper compartment permits gliding movements , and the lower, rotatory as well as gliding movements. Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi : CBS Publishers & Distributors Pvt Ltd; 2017. 19 Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

20. It rotates on the condyle like a handle of a bucket which is attached to lateral and medial poles of the condyle. The disc has a concavoconvex superior surface, and a concave inferior surface. The disc divides into an anterior band of 2 mm thick, a posterior band of 3 mm in thickness, and an intermediate band of 1 mm thickness which is thin in the center and bilaminar region containing venous plexus. 20 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

21. A ttachments The disc blends medially and laterally with the capsule , which is attached to the medial and lateral poles of the condyle. Antero-superiorly , the disc is attached to the articular eminence above and to the articular margin of the condyle below. Posteriorly, the disc is attached to the posterior wall of the glenoid fossa above and to the distal aspect of the neck of the condyle below.( This area is called as the posterior bilaminar zone or retrodiscal tissue which has a rich neurovascular supply. Sensory branches of auriculotemporal nerve are abundant here.) 21 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi : CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

22. 22 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi : CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005. Attachments Superiorly the anterior margin of the articular eminence. Inferiorly the anterior margin of the articular surface of the condyle Anteriorly the tendinous fibers of the superior lateral pterygoid muscle. Posteriorly region of loose connective tissue (highly vascularized and innervated), “retro discal tissue” ( bilaminar zone or posterior attachment

23. The disc represents the degenerated primitive insertion of lateral pterygoid . F unctions The disc prevents friction between the articulating surfaces . It acts as a cushion and helps in shock absorption . It stabilises the condyle by filling up the space between articulating surfaces. The proprioceptive fibres present in the disc help to regulate movements of the joint. 23 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

24. Okeson JP. Bell's oral and facial pain. Chicago, IL: Quintessence Publishing Co. Inc.; 2014. 24

25. Ligaments Ligaments have a significant role in protecting the structures. They do not take part actively into function of the joint but act as passive restrictive devices to hamper border movements. Primary ligaments (functional ligaments) Collateral ( discal ) ligaments The fibrous capsular ligament Temporomandibular /lateral ligament 25 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

26. Collateral ( discal ) ligament The collateral ligaments join the medial and the lateral margins of the articular disk to the condylar poles. They are also known as discal ligaments , and there are two types: The medial edge of the disk to the medial pole of the condyle is attached by the medial discal ligament and the lateral edge of the disk to the lateral pole of the condyle is attached by the lateral discal ligament . They cause the hinging movement of the TMJ . Pressure on these ligaments causes pain . 26 Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

27. The fibrous capsular ligament The whole TMJ is enclosed by the capsular ligament. It is a funnel-shaped capsule,which blends with the periosteum of the mandibular neck and it envelops the meniscus. It is attached above anteriorly to the anterior border of the articular eminence and posteriorly to the lip of the squamotympanic fissure and to the circumference of the cranial articulating surface and below to the neck of the condyle, on the lateral as well as on the medial aspect . 27 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

28. Lateral or Temporomandibular Ligament TMJ capsule is reinforced by this main stabilizing ligament. It extends downward and backward from the articular eminence to the external and posterior side of the condylar neck. Its posterior fibers are united with the capsular fibers. This ligament is composed of collagenous fibers that have specific length and poor ability to stretch, hence it maintains the integrity and limits the movement of TMJ. It mainly limits the anterior excursion of the jaw as well as prevents posterior Dislocation hence it is called as ‘check ligament ’ of TMJ. 28 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

29. Accessory Ligaments/ Minor ligaments Accessory ligaments make no contribution to joint activity. • The sphenomandibular ligament • The stylomandibular ligament. The sphenomandibular ligament is an accessory ligament,that lies on a deep plane away from the fibrous capsule. It is attached superiorly to the spine of the sphenoid, and inferiorly to the lingula of the mandibular foramen. It is a remnant of the dorsal part of Meckel’s cartilage 29 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

30. The stylomandibular ligament is another accessory ligament of the joint. It represents a thickened part of the deep cervical fascia which separates the parotid and submandibular salivary glands. It is attached above to the lateral surface of the styloid process, and below to the angle and adjacent part of posterior border of the ramus of the mandible. 30 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017. Malik NA. Textbook of oral maxillofacial surgery. New Delhi: Jaypee Brothers; 2005.

31. Muscles The muscles that make direct contact with TMJ are four: masseter, temporal, and two pterygoids all of which have bilateral attachment . All muscles attached to the mandible influence its movement to some degree. Muscle pairs may function together for symmetrical movement or unilaterally for asymmetrical movement . 1) Masseter It originates from the zygomatic arch with several muscular layers and inserts on the body of the mandible (lateral surface) and the coronoid process (lateral surface). Its primary task is to elevate the jaw. The innervation of the muscle is through the masseteric branch of 5 th (trigeminal) cranial nerve. 31 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

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33. 2) Temporalis It originates from the temporal fossa of the skull and the medial face of the zygomatic process; it inserts on the coronoid mandibular process. It elevates the mandible. It receives innervation by the branches of the trigeminal, third branch (deep temporal nerves). 3) Medial pterygoid The internal or medial pterygoid muscle originates from the medial pterygoid plate and from the maxillary tuberosity, to terminate on the medial face of the angle of mandible. It is innervated by the mandibular branch of the trigeminal nerve. It muscle elevates and protrudes the mandible. 33 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

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35. 4) Lateral pterygoid muscle From anatomic point of view lateral pterygoid is described as one muscle arising from two distinct heads. From functional point of view, it consists of two separate muscles; the inferior lateral pterygoid and the superior lateral pterygoid . The larger inferior lateral pterygoid muscle originates from the outer surface of the lateral pterygoid plate of the sphenoid bone & insert on the anterior surface of neck of condyle . 35 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

36. The smaller superior lateral pterygoid muscle arises from the greater wing of sphenoid and fuses with the inferior belly near its point of insertion. Fibers from the both bellies insert into the neck of the condyle 36 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

37. Relations of TMJ 37

38. Relations of Temporomandibular Joint Lateral 1 Skin and fasciae 2 Parotid gland 3 Temporal branches of the facial nerve 38 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

39. Anterior 1 Lateral pterygoid 2 Masseteric nerve and artery. Posterior 1 The parotid gland separates the joint from the external auditory meatus . 2 Superficial temporal vessels 3 Auriculotemporal nerve. 39 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

40. Medial 1 The tympanic plate separates the joint from the internal carotid artery. 2 Spine of the sphenoid, with upper end of the sphenomandibular ligament attached to it . 3 Auriculotemporal and chorda tympani nerves. 4 Middle meningeal artery. 40 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

41. Superior 1 Middle cranial fossa 2 Middle meningeal vessels Inferior 1 Maxillary artery and vein 41 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

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43. DEVELOPMENT OF TMJ TMJ derives from the first pharyngeal arch, where we can recognize a mesodermal part (muscles and vessels) and mesenchyme (from neural crests) for bones and cartilages. The development of TMJ divides into three stages: the blastemic stage; the cavitation stage and lastly, the maturation stage . Blastemic stage . It begins in the seventh/eighth week of gestation, where the formation of the glenoid fossa and condylar blastema occurs (a group of cells that remain long undifferentiated and, proliferating, give rise to sketches of organs ) Anatomy, Head and Neck, Temporomandibular Joint [Internet]. [cited 2021Jan14]. Available from: https://www.researchgate.net/publication/332230629_Anatomy_Head_and_Neck_Temporomandibular_Joint 43

44. Cavitation stage . The formation of the lower joint space begins. The blastema start to differentiate into multiple layers, to form the lower synovial layer and what will become the joint disk; this happens between the ninth and tenth weeks of gestation. Maturation stage . The upper joint space begins to form towards the eleventh week of gestation. TMJ will continue to form until the baby is born. Around 17 weeks the joint capsule is formed, while at 19 to 20 weeks the development of the cartilage inside the capsule can be recognized .  At birth, TMJ, compared to other types of synovial joints, is not fully developed. 44 Anatomy, Head and Neck, Temporomandibular Joint [Internet]. [cited 2021Jan14]. Available from: https://www.researchgate.net/publication/332230629_Anatomy_Head_and_Neck_Temporomandibular_Joint

45. 45 Anatomy, Head and Neck, Temporomandibular Joint [Internet]. [cited 2021Jan14]. Available from: https://www.researchgate.net/publication/332230629_Anatomy_Head_and_Neck_Temporomandibular_Joint

46. The child has a more obtuse mandibular arch, compared to the adult, which has a more angular shape; in the baby, the glenoid fossa is looser and, the cartilage is not yet present, but there will be a fibrous connective tissue. Between 5 and 10 years of age, the condyles grow in a posterior, lateral and upward direction; the joint shape will be further managed by the mechanical forces of the teeth and the chewing muscles. 46 Anatomy, Head and Neck, Temporomandibular Joint [Internet]. [cited 2021Jan14]. Available from: https://www.researchgate.net/publication/332230629_Anatomy_Head_and_Neck_Temporomandibular_Joint

47. Vascular supply and innervations Blood Supply Lateral aspect - Superficial temporal artery Deep and posterior aspect of retrodiscal capsule - Deep auricular, posterior auricular, and masseteric artery. Vascular supply to the lateral pterygoid muscle also supplies the condylar head by numerous nutrient foramina vessels Veins - Maxillary vein , Pterygoid venous plexus . Generally, the lymphatic system that affects TMJ comes from the area of the submandibular triangle . Nerve Supply Auriculotemporal nerve and masseteric nerve. 47 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

48. Schünke Michael, Schulte E, Schumacher U, Ross LM, Lamperti ED. Thieme atlas of anatomy. 3rd ed. Stuttgart: Thieme ; 2020. 48

49. MOVEMENTS OF TMJ 1 Depression (open mouth ) 2 Elevation (closed mouth) 3 Protrusion (protraction of chin) 4 Retrusion (retraction of chin) 5 Lateral or side-to-side movements during chewing or grinding. The movements at the joint can be divided into those between the upper articular surface and the articular disc, i.e. meniscotemporal (upper) compartment and those between the disc and the head of the mandible , i.e. meniscomandibular (lower) compartment. 49 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

50. In forward movement or protraction of the mandible,the articular disc with the head of the mandible glides forwards over the upper articular surface. Movement occurs in meniscotemporal compartment. In slight opening of the mouth or depression of the mandible , the head of the mandible moves on the undersurface of the disc like a hinge in lower compartment. In wide opening of the mouth, this hinge-like movement is followed by gliding of the disc and the head of the mandible in upper compartment, as in protraction. 50 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

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52. Chewing movements involve side-to-side movements of the mandible. In these movements, the head of (say) right side glides forwards along with the disc as in protraction, but the head of the left side merely rotates on a vertical axis. As a result of this, the chin moves forwards and to left side (the side on which no gliding has occurred ). Alternate movements of this kind on the two sides result in side-to-side movements of the jaw. 52 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

53. Muscles Producing Movements D epression is brought about mainly by the lateral pterygoid . The digastric, geniohyoid and mylohyoid muscles help when the mouth is opened wide or against resistance. E levation is brought about by the masseter, the anterior vertical, middle oblique fibres of temporalis, and the medial pterygoid muscles of both sides. These are antigravity muscles . 53 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

54. P rotrusion is done by the lateral and medial pterygoids and superficial oblique fibres of masseter. R etraction is produced by the posterior horizontal fibres of the temporalis and deep vertical fibres of masseter . Lateral or side-to-side movements, e.g. chewing from left side produced by right lateral pterygoid , right medial pterygoid which push the chin to left side . Then left temporalis (anterior fibres ), left masseter chew the food. 54 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

55. Movements of temporomandibular joint (arrows) by muscles of mastication 55 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

56. . Muscles involved in movement. Depression Lateral pterygoid , Digastric, Geniohyoid , Mylohyoid . Elevation Temporalis, Masseter, Medial pterygoid . Protrusion Medial pterygoid , lateral pterygoid . Retraction Posterior fibres of temporalis 56 Chaurasia BD, Garg K, Mittal PS, Chandrupatla M. BD Chaurasia's human anatomy: regional and applied, dissection and clinical. 8th ed. Vol. 3. New Delhi: CBS Publishers & Distributors Pvt Ltd; 2017.

57. Synovium and Synovial fluid Lining the capsular ligament is the synovial membrane, thin, smooth, richly innervated vascular tissue without epithelium. Synovial cells, which are of undifferentiated in appearance, serve both as a phagocyte and also as a secretor. Produce hyaluronic acid, which is present in the synovial fluid. Capable of rapid and complete regeneration following injury & have the capacity to differentiate into chondrocytes. Miloro M, Peterson LJ. Peterson's principles of oral and maxillofacial surgery. Shelton, CT: People's Medical Pub. House-USA; 2012. 57

58. Synovial fluid, lubricates the joint (less than 2ml). It comes from two sources from the plasma by dialysis and by secretion from the synovial cells. The latter component is hyalurinoprotein , a polysaccharide-protein complex ( depolymerization of the which may initiate the disease process & damage the joint). Initially it was thought that it is hyaluronic acid content gave the fluids the viscous properties, but recent work suggests that the main lubricant is protein moiety . 58 Miloro M, Peterson LJ. Peterson's principles of oral and maxillofacial surgery. Shelton, CT: People's Medical Pub. House-USA; 2012.

59. 59 The proteins in synovial fluid are similar to plasma proteins (↑albumin and ↓globulin). Leukocytes - less than 200 cells/mm3 Functions of synovial fluid include: Lubrication of the joint Phagocytosis of the particulate debris Nourishment of the articular cartilage. Protects the articular cartilage Assist in stabilization of the joint. Helps in progressive remodeling of the joint. Miloro M, Peterson LJ. Peterson's principles of oral and maxillofacial surgery. Shelton, CT: People's Medical Pub. House-USA; 2012.

60. Synovial fluid lubricates the articular surfaces by way of two mechanisms . The first is called boundary lubrication , which occurs when the joint is moved and the synovial fluid is forced from one area of the cavity into another . Boundary lubrication prevents friction in the moving joint and is the primary mechanism of joint lubrication. A second lubricating mechanism is called weeping lubrication. This refers to the ability of the articular surfaces to absorb a small amount of synovial fluid. During function of a joint, forces are created between the articular surfaces. These forces drive a small amount of synovial fluid in and out of the articular tissues. This is the mechanism by which metabolic exchange occurs. 60

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63. TMJ-CLINICAL EXAMINATION The clinical examination form the crucial step in the diagnosis of the temporomandibular disorders. It may be discussed under the following headings; INSPECTION On inspection, attention must be paid to local swelling, deformation, deviation of the chin and teeth wear . Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf 63 Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

64. Functional examination Active movements ; The influence of all five active movements on pain, range of movement, deviation , abnormal sounds and crepitus are noted. 1)Active opening of the mouth Because it is difficult to measure the range of motion of the TMJ in degrees, the interincisal distance at maximum opening is used. A restricted mouth opening is considered to be any distance less than 40 mm. A practical and quick way of checking range of motion is to ask the patient to insert the knuckles in between the front teeth. 64 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

65. 65 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf

66. In the absence of pain, the maximum comfortable opening and maximum opening are the same. 66 Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

67. If mouth opening is restricted, it is helpful to test the “ end feel ” The end feel describes the characteristics of the restriction that limits the full range of joint movement . The end feel can be evaluated by placing the fingers between the patient’s upper and lower teeth and applying gentle but steady force in an attempt to passively increase the interincisal distance. S oft end feel = muscle-induced restriction Hard end feel = intracapsular sources ( e.g., a disc displacement without reduction). 67 Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

68. 68 The path taken by the midline of the mandible during maximum opening is observed next . Two types of alteration can occur : Deviations and Deflections . A D eviation is any shift of the jaw midline during opening that disappears with continued opening (a return to midline ) It is usually due to a disc displacement with reduction in one or both joints and is a result of the condylar movement necessary to get past the disc during translation . Once the condyle has overcome this interference, the straight midline path is resumed. Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

69. D eflection is any shift of the midline to one side that becomes greater with opening and does not disappear at maximum opening (does not return to midline) It is due to restricted movement in one joint . Restricted movements of the mandible are caused by either Extracapsular sources ; muscle disorder Intracapsular sources ; disc derangement disorder 69 Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

70. 70 Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

71. 2)Active closing of the mouth The patient is asked to close the mouth. 3) Active deviation of the mandible to the left and right When the mandible deviates to the side it rotates around a vertical axis through the ipsilateral mandibular ramus. The contralateral mandibular head moves anteriorly at the same time. Any lateral movement less than 8 mm is recorded as a restricted movement . 71 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf

72. 72 Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

73. 73 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf

74. 4)Active forward protrusion of the chin This is performed by the lateral and medial pterygoid , masseter, geniohyoid and digastric muscle. When it is disturbed, this is usually the consequence of an existing problem. 74 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf

75. PALPATION Resisted movements 1)Resisted opening of the mouth The examiner places one hand underneath the patient’s chin, the other on the vertex. With the mouth open about 1 cm , the patient is now asked to open further while the examiner provides strong resistance , so preventing any movement . The strength of the lateral pterygoid is tested by this manœuvre . 75 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf

76. 2)Resisted closing of the mouth A rubber pad about 1 cm thick is put between the teeth. The patient is asked to bite as hard as possible. This is a test for all the muscles that close the mouth: masseter, temporal and medial pterygoid . 76 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf

77. 3)Resisted deviation of the mandible to the left and right The examiner puts one hand on the left side of the patient’s chin and holds the head stable by placing the other hand against the right temporal area. The patient is now asked to deviate the chin to the left against the resistance offered by the examiner’s hand . The test is repeated to the opposite side. This movement tests the contralateral lateral pterygoid . 77 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf

78. Resisted deviation of the mandible (a) to the left; (b) to the right. 78 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf

79. The joint is palpated during active opening and closing and during active deviation to the left and right. On opening, the TMJ is palpated with the finger below the zygomatic bone just anterior to the condyle or, as for closing, with the tip of the finger placed either just anterior to the tragus behind the condyle or in the external auditory meatus exerting some anterior directed pressure against the posterior aspect of the joint . The examiner normally feels a depression on opening. 79 Clinical examination of the temporomandibular joint [Internet]. [cited 2021Jan14]. Available from: https://www.orthopaedicmedicineonline.com/downloads/pdf/B978070203145800079X_web.pdf Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

80. Pain or tenderness of the TMJs is determined by digital palpation of the joints when the mandible is both stationary and during dynamic movement . The fingertips are placed over the lateral aspects of both joint areas simultaneously . The fingertips should feel the lateral poles of the condyles passing downward and forward across the articular eminences . Once the position of the fingers over the joints has been verified, the patient relaxes and medial force is applied to the joint areas. The patient is asked to report any symptoms, and they are recorded with the same numerical code that is used for the muscles. 80 Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

81. Once the symptoms are recorded in a static position , the patient opens and closes and any symptoms associated with this movement are recorded. As the patient opens maximally, the fingers should be rotated slightly posteriorly to apply force to the posterior aspect of the condyle. 81 A. Lateral aspect of the joint with the mouth closed. B. Lateral aspect of the joint during opening and closing. C . With the mouth fully open, the finger is moved behind the condyle to palpate the posterior aspect of the joint. Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

82. In order to graduate the patient’s response to palpation, score ranging from 0 to 3 can be used : - absence of pain on palpation 1 - mild pain 2 - moderate pain 3 - severe pain, palpebral reflex or “jump sign” It is not wise to examine the joint for sounds by placing the fingers in the patient’s ears. It has been demonstrated that this technique can actually produce joint sounds that are not present during normal function of the joint . It is thought that this technique forces the ear canal cartilage against the posterior aspect of the joint and either this tissue produces sounds or this force displaces the disc, which produces the additional sounds. 82 Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020.

83. Imaging Modalities 1. Two-dimensional -Conventional tomography. - Transcranial , transmaxillary , transpharyngeal projections. - Submentovertex projection. - Posteroanterior and lateral cephalometric projections. -Panoramic radiography: open and closed views. 2. Three-dimensional - Multislice computed tomography (MSCT) -Cone beam computed tomography (CBCT) -Magnetic resonance imaging (MRI) Karjodkar FR, Nagesh KS. Textbook of dental and maxillofacial radiology.2 nd ed. St. Louis: Jaypee Brothers Medical Publishers; 2009. 83

84. 84 Normal TMJ-CT Image Glenoid fossa Articular Eminence Condylar Head Articular Disc

85. 85 MRI-image of TMJ

86. Transcranial Karjodkar FR, Nagesh KS. Textbook of dental and maxillofacial radiology.2 nd ed. St. Louis: Jaypee Brothers Medical Publishers; 2009. 86 Transpharyngeal ( Infracranial or McQueen Dell Technique)

87. Karjodkar FR, Nagesh KS. Textbook of dental and maxillofacial radiology.2 nd ed. St. Louis: Jaypee Brothers Medical Publishers; 2009. 87 Lateral cephalogram Submento -vertex view

88. Karjodkar FR, Nagesh KS. Textbook of dental and maxillofacial radiology.2 nd ed. St. Louis: Jaypee Brothers Medical Publishers; 2009. 88 Oral pantomogram

89. Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020. 89 A three-dimensional image that has been reconstructed from a cone beam image

90. TMD-INDICES Helkimo Index Cranio -Mandibular Index Fonesca -Anamnestic Index RDC/TMD Index 90

91. Helkimo Index Helkimo developed the index ,In an epidemiological study of Lapps in Sweden. Helkimo Index is a questionnaire‑based survey comprised two parts: Anamnestic component ( which includes answers to questions in “yes” or “no ”) Clinical dysfunction part ( comprised clinical examination such as extraoral examination, palpation, and observation of palpebral reflex in all the subjects) Helkimo M. Studies on function and dysfunction of the masticatory system. Acta Odontologica Scandinavica . 1974;32(4):255–67. 91

92. A namnestic scale is as follows: • 0: No symptoms • I: Mild symptoms included sensation of the jaw fatigue, jaw stiffness, and TMJ sounds (clicking or crepitus) • II: Severe symptoms included one or more of the following: ( a) Difficulty in the mouth opening, (b) jaw locking,(c) mandible dislocation and its painful movement, and (d) painful TMJ region and/or masticatory muscles. Helkimo M. Studies on function and dysfunction of the masticatory system. Acta Odontologica Scandinavica . 1974;32(4):255–67. 92

93. Signs of TMJ Dysfunction   1. Impaired Range of Movement - Maximal opening less than 40 mm and 35 mm for men and women respectively. 2. Impaired TMJ Function - Deviation of mandible was recorded if the mandibular midline deviated at least 2mm during opening or closing. Stethoscope was used to record joint sounds of right and left sides after listening to each joint at least two times. During mandibular movements, locking and luxation were recorded. 3. Muscle Tenderness - Muscle tenderness was recorded by palpation of the temporalis, masseter, medial and lateral pterygoid muscles. Helkimo M. Studies on function and dysfunction of the masticatory system. Acta Odontologica Scandinavica . 1974;32(4):255–67. 93

94. 4. TMJ Tenderness - The joints were palpated from the lateral sides and via auditory meatus for tenderness. If found positive, there were recorded as palpable. 5. Pain on Movement of the Mandible - This was recorded when pain was present on wide mouth opening and during right and left lateral movements of the lower jaw. Scores assigned for the five symptoms was summed up. Each individual had a total dysfunction score ranging from 0 to 25 points. Helkimo M. Studies on function and dysfunction of the masticatory system. Acta Odontologica Scandinavica . 1974;32(4):255–67. 94

95. Helkimo M. Studies on function and dysfunction of the masticatory system. Acta Odontologica Scandinavica . 1974;32(4):255–67. 95

96. Helkimo M. Studies on function and dysfunction of the masticatory system. Acta Odontologica Scandinavica . 1974;32(4):255–67. 96

97. Higher the score, the more acute/serious the disorder. Depending on the values obtained, the patients were classified as follows: Di0 – no dysfunction DiI – mild dysfunction (1–4 points) DiII – moderate dysfunction (5–9 points ) DiIII – severe dysfunction (9–25 points). Helkimo M. Studies on function and dysfunction of the masticatory system. Acta Odontologica Scandinavica . 1974;32(4):255–67. 97

98. Craniomandibular Index J. R. FRICTON and E. L. SCHIFFMAN(1986) D ivided into those items that reflect temporomandibular joint tenderness and functioning problems, termed the Dysfunction Index (DI ) A nd those items that reflect muscle tenderness problems, termed the Palpation Index (PI). Fricton JR, Schiffman EL. Reliability of a Craniomandibular Index. Journal of Dental Research. 1986;65(11):1359–64. 98

99. 99 Fricton JR, Schiffman EL. Reliability of a Craniomandibular Index. Journal of Dental Research. 1986;65(11):1359–64.

100. 100 Fricton JR, Schiffman EL. Reliability of a Craniomandibular Index. Journal of Dental Research. 1986;65(11):1359–64.

101. The scoring of the CMI was designed to give equal weight and 0 to 1 scores to the DI and PI. To do this, the DI was calculated by using the sum of the positive responses related to mandibular movement and TMJ noise divided by the total number of items (20). The PI was calculated by using the sum of positive responses related to palpation of jaw and neck muscles and TMJ capsule divided by the total number of items(42). The CMI is the sum of the DI and PI divided by 2. 101 Fricton JR, Schiffman EL. Reliability of a Craniomandibular Index. Journal of Dental Research. 1986;65(11):1359–64.

102. The Fonseca Anamnestic Index( 1994 ) The Fonseca Anamnestic Index is a questionnaire used to classify individuals with temporomandibular disorders . The FAI is a patient-reported outcome in which a volunteer answered questions on the questionnaire. This index is a simple, easy, and low cost tool that displayed the signs and symptoms of TMD and classified the condition according to its severity. Pires PF, de Castro EM, Pelai EB, de Arruda AB, Rodrigues- Bigaton D. Analysis of the accuracy and reliability of the Short-Form Fonseca Anamnestic Index in the diagnosis of myogenous temporomandibular disorder in women. Brazilian Journal of Physical Therapy. 2018;22(4):276–82. 102

103. This index was created with 10 items with three answeroptions : ‘‘yes’’, ‘‘sometimes’’, or ‘‘no’’.10It consists of thefollowing items: 1 --- Do you have difficulty opening your mouth wide?; 2 --- Do you have difficulty moving your jaw from side to side?; 3 --- Do you feel fatigue or muscle pain when chewing?; 4 --- Do you have frequent headaches?; 5- -- Do you have neck pain or wryneck?; 6 --- Do you have ear aches or pain in your TMJs?; 7 --- Have you noticed any clicking in your TMJs while chewing or opening your mouth?; 8 --- Have you noticed if you have a habit of clenching or grinding your teeth?; 9 --- Do you feel that your teeth do not articulate well?; 10 --- Do you consider yourself a tense(nervous) person?   Pires PF, de Castro EM, Pelai EB, de Arruda AB, Rodrigues- Bigaton D. Analysis of the accuracy and reliability of the Short-Form Fonseca Anamnestic Index in the diagnosis of myogenous temporomandibular disorder in women. Brazilian Journal of Physical Therapy. 2018;22(4):276–82. 103

104. The volunteers are instructed to reply to ten questions by choosing one of the following answers indicating different degrees of TMD: yes (10 points) no (0 points) sometimes (5 points ). The sum of the points was used to classify the participants into four categories : TMD-free (0 to 15 points) mild TMD (20 to 40 ) moderate TMD (45 to 60) severe TMD (70 to 100) Pires PF, de Castro EM, Pelai EB, de Arruda AB, Rodrigues- Bigaton D. Analysis of the accuracy and reliability of the Short-Form Fonseca Anamnestic Index in the diagnosis of myogenous temporomandibular disorder in women. Brazilian Journal of Physical Therapy. 2018;22(4):276–82. 104

105. RDC/TMD ( Dworkin SF, LeResche L-1992) The Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) have been the most widely employed diagnostic protocol for TMD research since its publication in 1992 . This classification system was based on the biopsychosocial model of pain that included an Axis I physical assessment , using reliable and well-operationalized diagnostic criteria, and an Axis II assessment of psychosocial status and pain-related disability. Schiffman E, Ohrbach R, Truelove E, Look J, Anderson G, Goulet J-P, et al. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: Recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group†. Journal of Oral & Facial Pain and Headache. 2014;28(1):6–27. 105

106. The RDC/TMD (1992) was intended to be only a first step toward improved TMD classification, and the authors stated the need for future investigation. In March 2009, the International RDC/TMD Consortium Network- (IADR) and the Orofacial Pain Special Interest Group (of the International Association for the Study of Pain [IASP]) organized the “International Consensus Workshop: Convergence on an Orofacial Pain Taxonomy” at the IADR Conference in Miami to address the recommendations from both the Validation Project investigators and the 2008 Toronto meeting regarding development of the new DC/TMD. Schiffman E, Ohrbach R, Truelove E, Look J, Anderson G, Goulet J-P, et al. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: Recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group†. Journal of Oral & Facial Pain and Headache. 2014;28(1):6–27. 106

107. The recommended evidence-based new DC/TMD protocol is appropriate for use in both clinical and research settings. More comprehensive instruments augment short and simple screening instruments for Axis I and Axis II. In 2012, the new DC/TMD manuscript was then reviewed and finalized by the Miami 2009 workshop participants for publication. The newly recommended Diagnostic Criteria for TMD (DC/TMD) Axis I protocol includes both a valid screener for detecting any pain-related TMD as well as valid diagnostic criteria for differentiating the most common pain-related TMD Schiffman E, Ohrbach R, Truelove E, Look J, Anderson G, Goulet J-P, et al. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: Recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group†. Journal of Oral & Facial Pain and Headache. 2014;28(1):6–27. 107

108. 108

109. 109

110. The new DC/TMD protocol, like the original RDC/ TMD, needs to be further tested and periodically reassessed to make appropriate modifications to maximize its full value as new research findings are reported. Schiffman E, Ohrbach R, Truelove E, Look J, Anderson G, Goulet J-P, et al. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: Recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group†. Journal of Oral & Facial Pain and Headache. 2014;28(1):6–27. 110

111. Motghare V. Association Between Harmful Oral Habits And Sign And Symptoms Of Temporomandibular Joint Disorders Among Adolescents. Journal Of Clinical And Diagnostic Research. 2015;9(8)45-48. 111 Questionnaire recommended by American Academy of Orofacial Pain   According to guidelines of AAOP, three or more ‘Yes’ responses indicate TMD. Sarit S, Rajesh G, Mithun Pai BH, Shenoy R. Factors influencing the impact of temporomandibular disorders on oral health-related quality of life among school children aged 12–15 years in Mangalore: An observational study. Journal of Indian Association of Public Health Dentistry. 2019;17(1): 58-65

112. 112

113. WHO-Oral Health Assessment Form Oral health surveys : basic methods [Internet ]. World Health Organization; 1997 [cited 2021Feb17]. Available from: https://apps.who.int/iris/handle/10665/41905 113

114. Oral health surveys : basic methods [Internet]. World Health Organization; 1997 [cited 2021Feb17]. Available from: https://apps.who.int/iris/handle/10665/41905 114

115. TEMPOROMANDIBULAR JOINT DISORDERS(TMD) Classification i . Intra-articular origin or intrinsic disorders . ii . Extra-articular origin or extrinsic disorders . Extrinsic factors are those not directly associated with the TMJ, whereas intrinsic factors relate to those conditions existing within the confines of the capsule of the joint. Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005. 115

116. Disorders due to Extrinsic Factors Masticatory muscle disorders a . Protective muscle splinting. b . Masticatory muscle spasm (MPD syndrome). c . Masticatory muscle inflammation (myositis ). Problems that result from extrinsic trauma a . Traumatic arthritis b . Fracture c . Internal disc derangement d . Myositis, myospasm e . Tendonitis f . Contracture of elevator muscle— myofibrotic contractures . 116 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

117. Disorders due to Intrinsic Factors 1. Trauma a . Dislocation, subluxation b . Haemarthrosis c . Intracapsular fracture, extracapsular fracture 2. Internal disc displacement a . Anterior disc displacement with reduction b . Anterior disc displacement without reduction 3. Arthritis a . Osteoarthrosis (degenerative arthritis, osteoarthritis) b . Rheumatoid arthritis c . Juvenile rheumatoid arthritis d . Infectious arthritis 117 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

118. 4. Developmental defects a . Condylar agenesis or aplasia—unilateral/bilateral b . Bifid condyle c. Condylar hypoplasia d . Condylar hyperplasia 5. Ankylosis 6. Neoplasms a . Benign tumours: osteoma , osteochondroma,chondroma b . Malignant tumours: Chondrosarcoma , fibrosarcoma,synovial sarcoma. 118 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

119. Dislocation, Subluxation, Hypermobility of TM Joint During normal or unstrained opening of the mouth, the condylar heads translate forward to a position under the apices of the articular eminences . Excursion of the condylar heads beyond these limits may be viewed as abnormal and termed as dislocation . The dislocation can be unilateral or bilateral Acute or Chronic recurrent ( habitual ) subluxation 119 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

120. 120 Unilateral acute dislocation of (R) TM joint. (1) Extraoral picture showing inability to close the mouth and deviation of the mandible on the unaffected side. (2) Intraoral picture showing the deviation of the mandible Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

121. 121 Acute bilateral dislocation of TMJ (1) Clinical frontal face of a patient having acute bilateral TMJ dislocation. Elongated face (2) Depression in preauricular area. Prominence of dislocated head seen. (3) Anterior open bite with posterior molar gagging seen. (4) Original occlusion of patient, after reduction (5) Normal face after reduction. D = Depression, P = Prominence Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

122. Manipulation procedure Few drops of local anaesthetic solution may be injected in the glenoid fossa which will eliminate the pain factor and spontaneous reduction may occur. The thumbs are placed on the occlusal surfaces of the lower molars and fingertips are placed below the chin. Operator has to exert full body pressure and give downward pressure on the posterior teeth to depress the jaw and at the same time the fingertips are placed below the chin to elevate it by giving upward pressure. Immobilization can be carried out, by giving barrel bandage to the patient for the period of 10 to 14 days,NSAIDS 3-5 days,and patient is kept on semisolid diet. 122 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

123. 123 Injecting local anasthetic to glenoid fossa Manual reduction procedure

124. Chronic Recurrent or Habitual Dislocation or Subluxation The term should be reserved for repeated episodes of dislocation , where there is abnormal anterior excursion of the condyles beyond the articular eminence, but the patient is able to manipulate it back into normal position . So here the condylar head moves, unassisted,forward and backward over the articular eminence. The triad of ligamentous and capsular flaccidity, eminential erosion and flattening and trauma is well-recognized in the genesis of chronic recurrent subluxation . 124 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

125. management procedures is as follows : Intermaxillary fixation or limiting the oral opening by giving elastics Total immobilization of the jaw for the period of 3 to 4 weeks. Use of sclerosing solution injections into the joint space Sodium psylliate provided consistently best results. In the absence of effective sclerosing agent, chronic subluxation associated with severe pain and not responding to conservative line of treatment becomes a surgical problem. 125 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

126. In 1976, Miller and Murphy divided surgical procedures to correct recurrent condylar dislocation into five categories : 1 . Capsule tightening procedure. 2 . Creation of a mechanical obstacle or block. 3 . Direct restraint of the condyle. 4 . Creation of a new muscle balance. 5 . Removal of mechanical obstacle. 126 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

127. TMJ ankylosis Ankylosis is a Greek terminology meaning ‘stiff joint ’.That is abnormal stiffening and immobility of a joint due to fusion of the bones. Hypomobility to immobility of the joint can lead to inability to open the mouth from partial to complete. Classification of Ankylosis 1. False ankylosis or true ankylosis . 2. Extra-articular or intra-articular. 3. Fibrous or bony. 4. Unilateral or bilateral. 5. Partial or complete. 127 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

128. 128 The definite cause of ankylosis of TMJ is unknown . Two main factors predisposing to the ankylosis are trauma and infection in or around the joint region. In 1968,Topazian reported that 26 to 75 per cent of cases of TMJ- ankylosis are seen following trauma, while 44 to 68 percent are seen due to infection. Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

129. Unilateral Ankylosis Seen in a child or in a person where the onset was usually in the childhood. Obvious facial asymmetry. Deviation of the mandible and chin on the affected side. The chin is receded with hypoplastic mandible on the affected side. Roundness and fullness of the face on the affected side . The appearance of the flatness and elongation on the unaffected side. The lower border of the mandible on the affected side has a concavity that ends in a well-defined antegonial notch. In unilateral ankylosis some amount of oral opening may be possible. Interincisal opening will vary depending on whether it is fibrous or bony ankylosis . 129 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

130. Cross bite may be seen. Class II angles malocclusion on the affected side plus unilateral posterior cross bite on the ipsilateral side seen. Condylar movements are absent on the affected side. 130 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

131. Bilateral Ankylosis (Fig. 22.4) Inability to open the mouth progresses by gradual decrease in interincisal opening. The mandible is symmetrical but micrognathic . The patient develops typical ‘bird face’ deformity with receding chin. The neck chin angle may be reduced or almost completely absent. Antegonial notch is well-defined bilaterally. Class II malocclusion can be noticed. Upper incisors are often protrusive with anterior open bite. Maxilla may be narrow. 131 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

132. 132 Oral opening will be less than 5 mm or many times there is nil oral opening. Multiple carious teeth with bad periodontal health can be seen. Severe malocclusion, crowding can be seen and many impacted teeth may be found on the X-rays Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

133. Management of TMJ Ankylosis The treatment of TMJ ankylosis is always surgical . Number of techniques have been advocated by different surgeons. Critical analysis of all, filters only to three basic methods. I : Condylectomy II : Gap arthroplasty III : Interpositional arthroplasty Artificial Replacement of the Joint Prefabricated condylar prosthesis made of steel,vitallium or titanium have been also used extensively. Fossa liners along with specially constructed TMJ prosthesis reconstruct the entire joint. These are commercially available or custom fabricated. 133 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

134. Internal Derangement of the TM Joint Definition Internal derangement (ID) is a disruption of the internal aspects of the TMJ, in which an abnormal relationship exists between the disc and the condyle, fossa and articular eminence. Aetiology of Internal Derangement (ID) Multifactorial Microtrauma —overloading from bruxism and other parafunctional habits, hypermobility of the joint. Macrotrauma — obvious history of trauma and osseous morphologic changes. 134 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

135. Symptoms • Pain during function • Limited oral opening • Masticatory and cervical tenderness . Internal Derangements A . a. Disc displacement b . Disc displacement with reduction c . Disc displacement without reduction B. Structural incompatibility of the articular surfaces a . Adhesions b . Alterations in the form c . Due to systemic joint disorders like rheumatoid arthritis , etc . 135 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

136. Anterior Disc Displacement with Reduction Here the disc is dislocated anterior to the condylar head,resulting in pain during translation. There is reciprocal clicking in anterior dislocation with reduction, the patient demonstrates a click on opening and a click,usually less noticeable, on closing . During opening - Due to disc reduction, a clicking or popping sound ensues as the posterior part of the disc interferes with the condylar translation . During closing - Reciprocal click occurs again, as the condyle returns to the original position, gliding over the posterior part of the disc. 136 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

137. Anterior Disc Displacement without Reduction Here there is a closed lock form, where the disc interferes with condylar translation . Patient will not be able to open the mouth fully. Here, if patient attempts to open the mouth further, pain in the affected joint will be exhibited and deviation of the mandible towards the painful side will be noticed . This is because of the painful side remaining locked and it brings about translatory opening of the opposite side . If this chronic condition continues, then it will progress towards perforation of the disc. 137 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

138. Systemic Joint Diseases Causing Internal Derangement Degenerative type — pathology in the articular surface—osteoarthritis Inflammatory —rheumatoid arthritis, juvenile rheumatoid arthritis , ankylosing spondylitis, Reiter’s syndrome , lupus erythematosus . Disorders of immune system, hereditary factors. Infective arthritis —bacterial, viral. Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005. 138

139. Myofascial Pain Dysfunction Syndrome Myofascial pain dysfunction syndrome or Temporomandibular joint syndrome is the most common cause of facial pain after tooth ache. It is a pain disorder , in which unilateral pain is referred from the trigger points of the myofacial structures to the muscles of the head and neck. The pain is constant , dull aching type which is in contrast to the sudden sharp , shooting, intermittent pain of neuralgias (chronic pain). 139 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005. Anitha , Babu NA, Sankari SL, Malathi L. Myofacial Pain Dysfunction Syndrome - A Review [Internet]. Biomedical and Pharmacology Journal. 2016 [cited 2021Jan14]. Available from: https://biomedpharmajournal.org/vol9no2/myofacial-pain-dysfunction-syndrome-a-review/

140. But the pain may range from mild to intolerable. Clinically it has typical features such as a zone of reference, trigger points in muscles, occasional associated symptoms and presence of contributing factors. It is most common in females. The MPD type of temporomandibular disorder is not associated with destructive changes in the temporomandibular joint. Usually anxious and stressed persons and those with bruxism are commonly affected . 140

141. Etiology Multifactorial causes are said for MPDS. Malocclusion, jaw clenching, bruxism, increased pain sensitivity and stress and anxiety. The muscular hyperactivity and dysfunction due to malocclusion are the factors responsible for the clinical manifestations. Rather than mechanical factors emotional factors are primary etiologic factors in stimulating chronic oral habits that produce muscle fatigue. 141 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005. Anitha , Babu NA, Sankari SL, Malathi L. Myofacial Pain Dysfunction Syndrome - A Review [Internet]. Biomedical and Pharmacology Journal. 2016 [cited 2021Jan14]. Available from: https://biomedpharmajournal.org/vol9no2/myofacial-pain-dysfunction-syndrome-a-review/

142. Clinical Features Laskin's Four Cardinal Signs: Unilateral pain— it is generally a dull ache felt in the ear or the pre-auricular area or at the angle of the mandible. The pain is more often moderate on rising in the morning or relatively mild , but gradually becomes worse as the day progresses . Muscles tenderness— the most frequent areas are the neck of the mandible and the region distal and superior to the maxillary tuberosity. Clicking or popping noise in the TMJ. Limitation of jaw function or deviation of the mandible on opening. 142 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005. Anitha , Babu NA, Sankari SL, Malathi L. Myofacial Pain Dysfunction Syndrome - A Review [Internet]. Biomedical and Pharmacology Journal. 2016 [cited 2021Jan14]. Available from: https://biomedpharmajournal.org/vol9no2/myofacial-pain-dysfunction-syndrome-a-review/

143. Laskin emphasized that the patient must also have these negative characteristics: Absence of clinical, radiographic or biochemical evidence in the TMJ. Lack of tenderness in TMJ area, on palpation via the external auditory meatus. Treatment Most of the TMDs are selflimiting.Conservative treatments such as selfcare practices, rehabilitations to relieve muscle spasms . NSAIDS should be used for short term basis. Various modalities include patient education, medication, Physio -therapy , splints, psychological councelling , relaxation techniques, hypnotherapy , A cupuncture and arthrocentesis . 143 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005. Anitha , Babu NA, Sankari SL, Malathi L. Myofacial Pain Dysfunction Syndrome - A Review [Internet]. Biomedical and Pharmacology Journal. 2016 [cited 2021Jan14]. Available from: https://biomedpharmajournal.org/vol9no2/myofacial-pain-dysfunction-syndrome-a-review/

144. OCCLUSION AND TMJ DISORDER In dentistry, occlusion refers to the relationship of the maxillary and mandibular teeth when they are in functional contact during activity of the mandible. The term centric relation (CR) has been used in dentistry for many years . Although over the years it has had a variety of definitions, it is generally considered to designate the position of the mandible when the condyles are in an orthopedically stable position. The mode by which the teeth fit in together may influence the TMJ . Highest support to the joint and the muscle is provided by a steady occlusion with excellent tooth contact, whereas poor occlusion can cause the muscles to break down and eventually cause impairment to the joint. Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020. 144 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

145. Unsteadiness of the occlusion can amplify the force on the joint, causing destruction and deterioration . Development of functional disturbances in masticatory system could be be due to local and systemic events. Local events – Any change in sensory or proprioception such as crown, filling, traumatic injection or traumatic occlusion. Systemic events – Any change at the CNS level. Reaction to an event is different between individuals & influenced by local and systemic factors . Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020. 145 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

146. Local factor – orthopaedic stability Contact with all the teeth should be of even magnitude and simultaneous thus forces on individual teeth are minimized and condyle should be in their most anterosuperior position, therefore ideally ICP must coincides with CR. This is called as orthopaedic stability . Systemic factor – patient character, genetic, diet, disease and physical condition Okeson JP. Management of temporomandibular disorders and occlusion. 8th ed. St. Louis: Elsevier; 2020. 146 Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005.

147. TMD GENERAL MANAGEMENT STRATEGIES Explanation and reassurance TMD is not life‐threatening, chronic condition, managed . Education and self care Soft diet Jaw rest (especially during long dental appointments) Avoid extreme jaw movements ( eg ; yawning) Topical heat (e.g. heat packs) Protect face and jaws from cold weather. Avoid stress and anxiety. Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005. 147

148. Medications Anti-inflammatories Anxiolytics Muscle relaxants Antidepressants Jaw physiotherapy Massage and stretching Occlusal appliance therapy Psychotherapy Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005. 148

149. Behavioural therapy Lifestyle counselling Relaxation therapy Other Acupuncture Botox injections TMJ surgery Closed procedures TMJ arthrocentesis & arthroscopy Open procedures TMJ arthrotomy / arthroplasty TMJ joint replacements Malik NA. Textbook of oral maxillofacial surgery. 2 nd ed.New Delhi: Jaypee Brothers; 2005. 149

150. CONCLUSION The Temporomandibular joint is one of the most important yet most poorly understood of the many joints in the body, because of its unique anatomic position and association with other structures. Knowing the anatomy and biomechanics involving the temporomandibular joint helps in better diagnosis and understanding the diseases of temporomandibular joint to a large extent. Even though with high prevalence of Temporo -Mandibular Joint Disorders,the effective treatment options are still to be emerged. 150

151. PUBLIC HEALTH SIGNIFICANCE Temporomandibular disorders (TMD) are a significant public health problem affecting approximately 5% to 12% of the population. TMD is the second most common musculoskeletal condition (after chronic low back pain) resulting in pain and disability. Pain-related TMD can impact the individual's daily activities, psychosocial functioning, and quality of life. Schiffman E, Ohrbach R, Truelove E, Look J, Anderson G, Goulet J-P, et al. Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) for Clinical and Research Applications: Recommendations of the International RDC/TMD Consortium Network and Orofacial Pain Special Interest Group†. Journal of Oral & Facial Pain and Headache. 2014;28(1):6–27. 151

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