Abstract
We examined occlusal status in 18 patients with mandibular prognathism (mandibular prognathism group) as compared with that of 14 adults with normal occlusion (control group). We also studied changes in occlusal status after orthognathic surgery (1, 3, 6, and 12 months) in the patients with mandibular prognathism. The occlusal contact area, maximum voluntary isometric bite force, and occlusal pressure were recorded using a pressure-sensitive sheet (Dental Prescale ® 30HW type, Fuji Photo Film Co.) and the data were analyzed with an analysis system (FPD-703, Fuji Photo Film Co.).
The results were as follows:
1) Preoperatively, the mandibular prognathism group had a significantly smaller occlusal contact area and a lower bite force than the control group, but had a higher occlusal pressure.
2) Changes in occlusal contact area and bite force were evaluated in the patients with mandibular prognathism from before operation to 12 months after operation. Occlusal contact area and bite force decreased significantly 1 month after operation, increased significantly to preoperative levels 6 months after operation, and were about 40% of preoperative levels 12 months after operation. However, 12 months after operation occlusal contact area was smaller and bite force was lower than those in the control group.
3) Occlusal pressure was evaluated in the patients with mandibular prognathism from before operation to 12 months after operation. The value increased significantly 1 month after operation, but decreased subsequently. Twelve months after operation, occlusal pressure in the prognathism group was similar to that in the control group.
4) Few studies have used pressure-sensitive sheets. This method permits assessment of occlusal status of all teeth easily and promptly. Pressure-sensitive sheets are useful for understanding occlusal status clinically.
