Temporomandibular Joint Disorder
The temporomandibular joint (TMJ) is complex articulation between condylar head of the mandible and glenoid fossa of the temporal bone.
Patients frequently consult a dentist because of pain of dysfunction in TMJ region the most common causes of this disorder are muscular which are commonly referred as a myofascial pain and dysfunction other cause include internal derangement of TMJ structures.
so management of these patients requires a coordinated plan between the general dentist, oral and maxillofacial surgeon and other health care services.
Evaluation:
this evaluation include a thorough history, physical examination of the masticatory system and some types of routine TMJ radiography
Radiographical evaluation:
the use of radiographs ,should be based on the patient's signs and symptoms instead of routinely ordering standard set of radiographs.panoramic radiograph :this is one of the best overall radiographs for screening evaluation of TMJ this allow to see both joints on the same films which provide a good assessment of the bony anatomy of the condyle and glenoid fossa and other areas such as the coronoid process
• Tomograms:
• this technique allows radiographical sectioning of the joint at deferent levels of the condyle and fossa complex which provides individual views visualizing the joint in slices from the medial to the lateral pole. these views eliminate bony super impostion, and overlap and provides a relatively clear picture of the bony anatomy of the joint.
TMJ arthrography :
this involves the injection of contrast material into the inferior or superior spaces of the joint after which the joint is radiographed and this well allows evaluation of the position and morphology of the articular disk and to demonstrates the presence of perforations and adhesions of the disk or its attachments.
• Computed tomography:
provides evaluation of a variety of hard and soft tissue pathology in the joint which can be done from a single radiation exposure. + CT images provide the most accurate radiographic assessment of the bony components of the joint
• magnetic resonance imaging:
• which is most effective diagnostic imaging technique to evaluate TMJ soft tissue (intra-articular soft tissue) and for disk morphology and position with the fact that this technique does not use ionizing radiation is a significant advantages
Diseases of TMJ :A. traumatic arthritis:
an injury which is insufficient to produce a fracture of the condylar neck or dislocation may yet be sufficient to produce arthritis following the injury the patients complains of pain and limitation of movement of the joint. There is slight puffiness is markedly tender and prominent. in the radiograph will demonstrate widening of the joint space,treatment is immobilization of the jaw with a pair of eyelet wires on each side for few days with reassurances and analgsics
The clinical features of the traumatic arthritis are:1. Positive history of trauma.2. Pain, tenderness and swelling over the TMJ.3. Trismus and restricted excursions.4. There is open bite on the involved side due to effusion of exudates or blood (hem arthrosis) in the joint space.6. X-ray shows widening of the joint space.
B. acute subluxation:
in this condition phenomena observed including the• slight deviation of the chin towards the opposite side
• when patient at rest there is sudden onset of limitation of opening
• pain with movement of the affected joint,
exactly what happens within the joint is not known it is usually postulated that the condyle head manages to slip backwards over theposterior thickening of the disk.
• muscle spasms.
C. Dislocation:
dislocation of the condyle head upwards and forwards into the temporal fossa occurs when the masticatory muscles contract at a time when the mouth is open to its greatest extent or when blow is delivered to the point of the chin. reduction is accomplished by downward pressure with the padded thumbs on the lower molars together with an upwards and backwards force applied to the underside of the chin with fingers in some times will be necessary to vestor to anasthesia to produce the muscular relaxation necessary for success. chronic dislocation is seen almost always in edentulous patients• D.Tearing of the disk:
• in this case movement of the condylar head is restricted and the damaged meniscus used to be blamed as the cause of the painful and locking joint. if the disk lies behind the condyle so it cannot return to its proper position in the glenoid fossa.
E. Ankyloses of the TMJ:
ankyloses can be a sequel to an intra-capsular fracture of the condyle Intra capsular ankyloses results from a fusion of the condyle, disk, and fossa complex as a result of the formation of fibrous tissue, bone fusion, or a combination of the two .The most common cause of ankyloses involves macro trauma, most frequently associated with condylar fractures.
Operations is the treatment to free an ankyloses. the bony or fibrous attachment is divided and the abnormal tissue removed. three manoeuvers are employed to try to prevent reattachment:1. The part of the mandible adjacent to the joint may be widely excised2. soft tissue such as muscle or dermis may be interposed between the bone ends3. allograft material can be inserted in the gap or over one of the bone ends.
F. infective arthritis of TMJ:
this is a common complaint which is suppurative arthritis from staphylococcal infection may arise as a result of a penetrating injury of the joint or by spread of infection from adjacent structures involvement of the condylar head following an osteomyelitis of the ramus is one mechanism and extension of infection from otitis media is another .H. Suppuritive arthritis:
should be treated by aspiration of the joint, the instillation of an antibiotic solution and the administration of a systemic antibiotic a smear should be made from the aspirate and a sample sent for culture and sensitivity testG. Rheumatoid disease :
Rheumatoid arthritis is an autoimmune Inflammatory condition in which the inflamed and hypertrophic synovial membrane grows on to the articulating surfaces.
R. arthritis can affect the TMJ which is one of many joints elsewhere affected so in general the patient management will be in the hands of a rheumatologist. the symptoms include pain, particularly on movement, some swelling of the overlying tissues and limitation of opening. radiographically the condylar head and articular fossa will be less radio-opaque than usual and erosion of the articular surface of the condyle may be seen.
Treatment is directed towards:
elimination of al local causes of joint strain pain relief and algetic,reduction or suppression of inflammation-NSAID or corticosteroids and physiotherapy.
High condylotomy or joint replacement in the patients with severe joint destruction may be required.
Osteoarthritis:
irregular, perforated, or severely damaged disks in surface association with articular surface abnormalities such as articular flattening, erosions
The mechanisms of TMU degenerative diseases are not clearly understood but are thought to be multifactorial. Current concepts of DJD incorporate three possible mechanisms of injury:
(1) direct mechanical trauma,
(2) hypoxia reperfusion injury, and
(3) neurogenic inflammation
this is detected mostly in the older age groups but can be found affecting joints which have previously suffered a fracture
the joint is painful often has a palpable and audible grate when the mouth is opened and is tender to palpation
radiographs can demonstrate localized resorption .cavities in the condylar head, sclerosis of the underlying bone and occasionally small cystic cavities
treatment consist of a full range of conservative measures such as
1. analgesics,
attention to the occlusion
the use of short wave diathermy
altering the mechanics of the joint with bite raising appliance or the provision of new dentures which restore the proper vertical dimension
