A survey of temporomandibular joint dislocation: aetiology, demographics, risk factors and management in 96 Nigerian cases.

A retrospective study of 96 cases of temporomandibular joint dislocation was undertaken. Patients' ages ranged from 9 to 85 years (mean+/-SD, 35.3+/-17.4 years) and peak incidence was at 20-29 years. Mean duration was 7.9 weeks (range, 1h to 3 years). Acute, chronic and recurrent dislocations were seen in 46 (47.9%), 29 (30.2%) and 21 (21.9%) patients, respectively. Males dominated in all three categories but this was not statistically significant (P = 0.8). Excessive mouth opening while yawning (44 cases) was the commonest cause of dislocation, followed by road traffic accidents (13 cases). Ten patients (10.4%) had an underlying systemic disease, the commonest being epilepsy (four cases); those with acute dislocation recorded the highest incidence of underlying illness. Bilateral anterior (86 cases) dislocations were the most frequent. Of the 96 patients, 89 (92.7%) were available for treatment. Manual reduction with or without anaesthesia proved effective for 38/45 acute, 5/24 chronic and 14/20 recurrent cases. Chronic dislocations were treated mainly by surgical osteotomy (13/24). Vertical subsigmoid and oblique ramus osteotomies were the commonest surgical techniques recorded. Treatment was satisfactory for all patients surgically handled except for one case of anterior open bite postoperatively. This study has shown that excessive mouth opening while yawning is the commonest cause of temporomandibular joint dislocation in Nigerians, and conservative approaches to management remain quite effective irrespective of the duration and clinical subtype. The best choice of surgical technique should be determined by proper clinical evaluation and the need to avoid or minimize postoperative morbidity.