[Study for searching equilibrium point in dentulous hemimandibulectomy patients]

Occlusal registration for prosthodontic rehabilitation in dentulous hemimandibulectomy patient has various difficulties due to mandibular instability. The purpose of this study was to find the occlusal contact position for remaining dentition to stabilize the hemiresected mandible during clenching. Three hemimandibulectomized subjects without surgical bony construction were selected and custom-made Gothic-arch typed apparatus was fabricated. Mandibular movements during clenching were recorded with jaw movement tracking device with six degrees of freedom. The results were as follows: 1. The direction of the mandibular rotation around each coordinate axis in 3-dimensional space during clenching was constant in each subject, regardless of stylus position. 2. The most stable points on the hemimandibules during clenching did not necessarily correspond to the mid-portion of the remaining dentition of the mandible. 3. When referred to the maxillary arch, the point was lined up within the distal half of the second premolar and the mesial third of the first molar in mid-sagittal plane along the long axis of the remaining dentition. 4. Rotational axis during clenching existed on the horizontal plane. 5. It was assumed that the most stable point of the mandible in a hemimandibulectomy patient may be useful in interocclusal registration in clinical dental practice.