Inclination of the occlusal plane and occlusal guidance as contributing factors in mastication.
OBJECTIVE
The purpose of the present study was to compare the inclination of the occlusal plane with occlusal guidance as a contributing factor to masticatory movement.


METHODS
Masticatory movements of 41 young adults were measured using a 3-D mandibular movement analysing system. The inclination of the occlusal plane was measured in the sagittal plane using a 3-D digitizer. The contribution of the occlusal guidance and the inclination of the occlusal plane to the direction of the masticatory path of closure was evaluated at various closing levels.


RESULTS
The masticatory path of closure outside the intercuspal range was influenced mainly by the inclination of the occlusal plane, and the masticatory path of closure near the intercuspal range was only influenced by occlusal guidance. The so-called gliding type masticatory pattern was observed predominantly in subjects with a posteriorly inclined occlusal plane. In contrast, a chopping type masticatory pattern was observed predominantly in subjects with an anteriorly inclined occlusal plane.


CONCLUSIONS
The contribution of the inclination of the occlusal plane to masticatory movement was greater than that of occlusal guidance throughout the closing phase except near the intercuspal range.
Ogawa
T
T
Department of Removable Prosthodontics, Faculty of Dentistry, Kyushu University, Fukuoka, Japan. tack@dent.kyushu-u.ac.jp
Koyano
K
K
Umemoto
G
G
D000328:Adult; D001696:Biomechanical Phenomena; D002508:Cephalometry; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D007574:Jaw Relation Record / Q000295:instrumentation; D008297:Male; D008334:Mandible / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D009068:Movement