temporo mandibular joint disorders and its histology

TMJ disorders

1. Disorders of TMJ

2. BONY STRUCTURE OF TMJ

3. NON-BONY STRUCTURE OF TMJ

4. ANATOMY OF THE TMJ LIGAMENTS OF TMJ Fibrous capsule Lateral ligament Sphenomandibular ligament Stylomandibular ligament

5. DEVELOPMENTAL DISTURBANCES OF THE TMJ - Aplasia of the mandibular condyle - Hypoplasia of mandibular condyle - Hyperplasia of mandibular condyle - Double condyle

6. TRAUMATIC DISTURBANCES OF THE TMJ - Subluxation and luxation ( incomplete and complete dislocation) - Ankylosis ( hypomobility ) - Injuries to the articular disc - Fractures of the condyle

7. ARTHRITIS OF THE TMJ - Osteoarthritis (degenerative joint disease) - Rheumatoid arthritis -Arthritis due to specific infection

8. Injuries of articular disc: Internal Derangement Myofascial Pain Dysfunction Syndrome Neoplastic Disturbances of the TMJ Cysts of the Temporomandibular Joint Secondary to Infections Metabolic Disturbances leading to TMJ Pathology

9. APLASIA OF THE MANDIBULAR CONDYLE Failure of development of the mandibular condyle . ETIOLOGY: - Hemifacial macrosomia - Treacher Collins syndrome - Pierre Robin syndrome CLINICAL FEATURES: Age: Since birth Gender: No gender predilection Symptoms- Free movement Asymmetry of face seen in unilateral cases Mastication difficult

10. Signs- Unilaterally or bilaterally Shift of mandible to affected side in unilateral case Anterior open bite Altered occlusion • Associated anomalies- Defective and absent external ear Underdeveloped mandibular ramus Macrostomia • Radiological Features- Absence of condyle MANAGEMENT: - Dental intervention by establishment of acceptable plane of occlusion - Osteoplasty , if derangement is severe and correction of the malocclusion by orthodontic appliance

11. APLASIA OF LEFT CONDYLAR PROCESS

12. HYPOPLASIA OF THE MANDIBULAR CONDYLE • Underdevelopment or defective formation of mandibular condyle . • Unilateral or bilateral ETIOLOGY: Congenital or acquired CAUSES : Due to any agent interfering with normal development of the condyle May occur due to trauma during forceps delivery, External trauma to condylar area, X-ray radiation over TMJ area for local treatment of skin lesions like hemangioma or “birth mark”, Infection spreading from dental area or by hematogenous route may involve joint.

13. HYPERPLASIA OF THE MANDIBULAR CONDYLE • Rare unilateral/bilateral enlargement of the condyle . ETIOLOGY: Developmental: hemifacial hypertrophy Neoplastic : chondroma , osteochondroma , or osteoma of condyle Bone disease: fibrous dysplasia, Paget’s disease Endocrine: gigantism, acromegaly

14. CLINICAL FEATURES: Age: Occurs most commonly in 15-19 years Gender: No gender predilection Symptoms/Signs: Unilateral: - Facial asymmetry and shifting of midline of chin to unaffected side, with resulting cross-bite, or open-bite on affected side - Asymmetric protrusion Bilateral: - Anterior cross bite - Disproportion between normal size of crown of teeth and larger size of jaw bones.

15. DOUBLE CONDYLE ETIOLOGY: Persistence of well vascularized fibrous tissue septa Possible rupture of some of blood vessels contained within septa might impair ossification of condyle so as to cause bifid development of condylar head Trauma or fracture of the condylar head

16. TRAUMATIC DISTURBANCES OF THE TMJ - Subluxation and luxation ( incomplete and complete dislocation) - Ankylosis ( hypomobility ) - Injuries to the articular disc - Fractures of the condyle

17. LUXATION AND SUBLUXATION LUXATION : Complete dislocation SUBLUXATION: Partial or incomplete dislocation, a form of hypermobility . May be unilateral or bilateral positioning of condyle anterior to articular eminence, with repositioning to normal accomplished physiologic activity. Is self regulating and generally follows stretching of capsule and ligament. ETIOLOGY: - Long continuous opening of the mouth -Oral surgical procedures- excessive movement causes stretching of joint ligament or rupture of external pterygoid attachment

18. UNILATERAL ACUTE DISLOCATION

19. ANKYLOSIS Greek word meaning stiff joint. Abnormal immobility CLASSIFICATION: TRUE- Intra-articular : Condition producing fibrous or bony adhesion between articular surfaces of TMJ. FALSE- Extra-articular : Resulting from pathologic conditions outside the joint resulting in limited mandibular mobility. BONY- Bone present between articulating surfaces and prevents movements. FIBROUS- Medium which prevents movements is fibrous. PARTIAL- Incomplete union between articulating surfaces. COMPLETE- C omplete union between articulating surfaces

20. ETIOLOGY: FALSE- Myogenic: Fibrosis at muscle origin resulting from chronic infection of elevator muscle of mastication. Myositis ossificans can produce limitation of opening. Neurogenic- Epilepsy, brain tumor, bulbar paralysis and cerebrovascular accidents. Psychogenic- Hysterical trismus, produced due to fright. Bone impingement- Coronoid impingement owing to exostosis or elongation leading to impingement of mandible on the posterior aspect of zygoma. Trauma- Formation of fibrous adhesions or cicatricial bands of scar tissues. Neoplastic disease like osteochondroma.

21. TRUE- Congenital- abnormal intrauterine development, birth injuries and congenital syphilis Trauma- Trauma to chin forcing the condyle against glenoid fossa . Malunion of condylar fractures Injuries associated with malar-zygomatic compound. Inflammatory- Primary inflammation of joint Inflammation secondary to local inflammatory process Inflammation of joint secondary to blood stream infection Inflammation secondary to radiation therapy Rheumatoid arthritis Others- loss of tissue with scarring and metastatic malignancy

22. Signs: Class II malocclusion, protrusive incisors and anterior open-bite.

23. HISTOPATHOLOGICAL FEATURES: - Atrophic or destructive changes in cartilaginous component of joint with loss of meniscus - Progressive destruction of joint tissue with narrowing of joint space. - Normal soft tissue are replaced by thick fibrous bands, which blend in with periarticular tissue. - Overall flattening of articulation, with glenoid fossa and articular eminence becoming less pronounced and condylar process become enlarged. - Enlarged condyle is composed of dense sclerotic bone - Union of injured part is by granulation tissue It is replaced by dense fibrous connective tissue formation of fibrous cartilage metaplasia of fibrous cartilage direct transformation into bone ankylosis .

24. INTERNAL DERANGEMENTS Defined as abnormality of the internal components of the joint, where the articular disc is displaced from its normal functional relationship with the condylar head and the articular fossa of the temporal bone Etiology Injury to the condylar region Variation of normal function Muscle hyperactivity or excessive opening of the mouth Multiple excessive forces over a period of time such as bruxism

25. PATHOGENESIS :- (I) Increased muscle tone of lateral pterygoid Pull disc anteromedially to condylar head Disc will move anterior to the condylar head Click or pop will then occur on early opening

26. FRACTURES OF THE CONDYLE Condylar fractures can be classified according to the anatomic locations Condylar head Condylar neck Subcondylar region Can also be classified as Non-displaced, deviated, displaced and dislocated Depending on the orientation of the fracture line Horizontal Vertical Compression type

27. ETIOLOGICAL FACTORS LEADING TO CONDYLAR FRACTURES:- 1.Intentional trauma- interpersonal violence 2.Unintentional trauma When a blow is given on the face resulting in fracture of mandibular condyle, the position of fractured condyle in relation to remainder of the ramal stump depends upon certain factors:- 1. The direction and degree of force 2. The precise point of application of force 3. Whether the teeth were in occlusion at the time of injury 4. Whether the patient is partially or fully edentulous

28. DIAGNOSTIC FINDINGS OF THE CONDYLAR FRACTURES:- 1. Evidence of facial trauma, especially in area of mandible and symphysis 2. Localized pain and swelling in the region of TMJ 3. Limitation in opening 4. Deviation, upon opening, toward the involved side 5. Posterior dental open bite on the contralateral side 6. Shift of dental occlusion toward the ipsilateral side with possible cross bite 7.Lack of condylar movement upon palpation 8. Difficulty in lateral excursions as well as protrusion

29. ARTHRITIS OF THE TMJ - Osteoarthritis (degenerative joint disease) - Rheumatoid arthritis - Arthritis due to specific infection

30. ARTHRITIS DUE TO SPECIFIC INFECTION Also called as septic arthritis. May be acute or chronic ETIOLOGY: Microorganisms: Cause by direct spread organisms like staphylococci, streptococci, pneumococci and gonococci, from an infected mastoid process, tympanic cavity or via blood. Trauma: Trauma directly to the joint or infection from a maxillary molar and parotid gland Osteomyelitis and middle ear infection

31. PATHOLOGY:- Inflammation of joint capsule Exudation into potential joint space Become converted to pus Digestion of articular cartilage as a result Of proteolytic action of the invading organisms

32. ACUTE INFECTIVE ARTHRITIS:- Clinical Features:- Age: Usually occurs in young children Gender: No gender predilection Symptoms: Severe pain on jaw movement Inability to place the teeth in occlusion Signs: Redness and swelling over the joint Joint space: Exudation into joint space which may soon be converted to pus Lymph nodes: Tenderness

33. RHEUMATOID ARTHRITIS Is a debilitating systemic disease of unknown origin. It is characterized by progressive involvement of periarticular structures of joint. Bony components of TMJ are affected secondary to granulomatous involvement of synovial membrane spreading to articular surface of the condyle. ETIOPATHOGENESIS:- - Manifestations are probably due to a two phase process. - Phase one result from some systemic infection, which evokes inflammatory response within joint. - Phase two as an autoimmune reaction to antigen generated by initial inflammation itself or may by derangement of immune response to exogenous antigen.

34. Symptoms: - Bilateral stiffness - Crepitus - Tenderness - Swelling over the joint - Fever - Malaise - Fatigue - Weight loss Polyarthritis : - Large and weight bearing joints are usually affected

35. HISTOPATHOLOGICAL FEATURES: - Ingrowth of granulation tissue to cover the articular surfaces -Invasion of cartilage and its replacement by granulation tissue -Ultimate destruction of the articular cartilage - Fibrous adhesions occur, articular disc may become eroded fibrous ankylosis occurs

36. OSTEOARTHRITIS Also called as osteoarthrosis or degenerative arthritis. Condition due to wear and tear and more common in patients more than 50 years of age ETIOPATHOGENESIS:- - Increase in functional demands of healthy tissue or by deterioration in functional capacity of tissue - Breakdown of joint may occur when tissues subjected to repetitive overload in excess of their functional capacity or with normal load when capacity is reduced as part of aging process. - Degenerative joint disease may develop when remodeling rate of bone exceeds that of cartilaginous repair.

37. Radiographic features Condyle has osteophytes Condyles or fossa / eminence has subcortical erosion Condyles or fossa / eminence has subcortical pseudocysts

38. Ely’s cyst

39. Histopathology Surface erosions of varying degrees of severity Presence of vertical cracks extending from the surface through the cartilaginous plate into the subchondral bone Cartilage cells often exhibit degeneration Complete destruction of cartilage in localized areas

40. MYOFASCIAL PAIN DYSFUNCTION SYNDROME HISTORY - Costen in 1934 indicated occlusal etiology in TMJ pain. - Schwartz in 1956 coined the term TMJ pain dysfunction syndrome and blamed spasm of masticatory muscle leading towards the symptoms. - Laskin in 1969 gave the name myofacial pain dysfunction syndrome and implicated psychophysiologic theory stating that psychological stress leads to myospasm .

41. Pathogenesis: T he vicious cycle Anxiety, Stress Para-functional habit Muscle fatigue & Pain Excessive strain on muscles Neuro-muscular imbalance, Chronicity Depression Malocclusion Jaw injury, surgery Occlusal trauma

42. Laskin’s four cardinal signs 1. Pain- Dull ache felt in ear or pre-auricular region or at angle of mandible. 2. Muscle tenderness- Neck of mandible and in region distal and superior to maxillary tuberosity 3. Clicking or popping noise in TMJ 4. Limitation of jaw function or deviation of mandible on opening

43. MANAGEMENT:- 1. Counselling - Education regarding present illness 2. Trigger point therapy- (a) Spray and stretch therapy: Use of fluoromethane and then stretching muscle (b) Intramuscular trigger point injection therapy 3. Muscle relaxation technique and muscle exercise-

44. 4. Pharmacotherapy Pain control: Achieved by analgesics - Aspirin: 2 tabs 0.3-0.6 gm/4hrly - Ibuprofen: 200-600 mg/3 times a day - Piroxicam : 10-20 mg/3-4 times a day - Pentazocine : 50mg/ 2-3 times a day Anxiolytic agents: Tab Diazepam 5mg at bedtime for 7 days Tab Chlordiazepoxide : 5-10mg/2-3 times a day

45. Tricyclic antidepressants: Tab Amitriptyline 10 mg at night for 7 days Muscle relaxants: Tab Cyclobenzapine 10 mg at bedtime for 5 days Tab Methocarbamol : 500 mg/2-3 times a day 5. Bruxism prosthesis:- - Soft mouth guard - Anterior occlusal prosthesis - Mandibular posterior coverage - Complete maxillary or mandibular coverage

46. 7. Psychotherapy:- Includes three step program which includes basic relaxation exercises, sleep preparation and containment strategies for worry, grief and guilt. 8. Physical medication:- - Hot packs - Massage - Diathermy and ultrasound 9. Anesthesia:- - LA followed by series of exercises (0.5 ml of 0.5% xylocaine ) 10. Acupuncture

47. 11. Surgery:- - Eminectomy , menisectomy followed by prosthesis - High condylectomy with material interposed between articulating surfaces 12. Orthopedic stabilization:- - Restoration - Prosthodontic treatment - Orthodontic treatment - Orthognathic therapy

48. Assessment of patient with TMJ disorder: Extra-oral Examination TMJ Disorders Inspection: Facial symmetry Facial swelling, injury Deviation on movement Amount of mouth opening and lateral excursive movements Audible click Palpation: Joint movement Joint tenderness Masticatory muscle tenderness Crepitus Auscultation Joint sounds

49. Assessment of patient with TMJ disorder: Intra-oral Examination TMJ Disorders Teeth, periodontium, occlusion, prosthesis Signs of para-functional habits Grinding: flattening of cusps Clenching : deepening of central fossae (‘ bruxo -facets’) Tapping: Selective abrasion of opposing teeth Over-closure or high points of restorations Tongue: indentation on lateral border

50. Assessment of patient with TMJ disorder: Imaging and other investigations TMJ Disorders Routine: Panoramic Transcranial, transpharyngeal, transorbital Reverse Townes Advanced: CT MRI 3 Other : Electromyography

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52. PATHOGENESIS:- Muscle contraction; energy released Formation and accumulation of lactic acid Changes in osmolality resulting in decrease in pH Muscle receptor prone to impulse excitation Decrease in pH, lactic acid itself causes infusion and effusion of histamine, bradykinin and serotonin Pathologic muscle derangement (TRIGGER ZONES) Impulse bombards the CNS and gives rise to referred pain