The effect of anteroposterior inclination of the occlusal plane on biting force.

1 he orientation of the occlusal plane is an important clinical procedure in prosthodontic treatment for edentulous patients. Many dentists position the anterior end of the occlusal plane 1 to 3 mm below the resting upper lip and make the posterior end parallel to the ala-tragus line, According to surveys made by Levin and Sauer,’ Kawabe and associates,’ and Ukai and associates,” the concepts concerning the occlusal plane orientation differ considerably among dental schools in Japan. the United States, and Canada (Table I). Two important questions are whether the alatragus line is best and whether the inclination of the occlusal plane affects masticatory function. Sharry’ stated that the plane of orientation established on the ala-tragus line is not rigid, but can be altered for special reasons. Boucher and associates” pointed out that the ala-tragus plane is adequate for many patients and usually results in satisfactory dentures, but it certainly cannot be regarded as applicable to all patients. Kapur and Soman’ and Carey’ have shown that masticatory performance is influenced by the inclination of the occlusal plane. There have been no published reports regarding masticatory muscle activity and biting force with the occlusal plane placed at various inclinations. The purpose of the present study was to investigate the effect of anteroposterior inclination of the