Abe Haruomi, Miura Hiroyuki, Okada Daizo, Kato Hitoshi, Shin Chiharu
Fixed Prosthodontics, Department of Restorative Sciences, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University.
J Med Dent Sci. 2011 Jul 4;58(2):41-8.
It has become clear that food crushing is performed in the circumscribed region between functional cusps, that is, at "the main occluding area". However, the position of the main occluding area in patients with fixed partial dentures (FPDs) has not been investigated quantitatively yet. There is a possibility that the load onto the abutment teeth of FPDs is loaded excessively depending on the position of the main occluding area at the early stage of mastication. Therefore the position of the main occluding areas of the FPDs was investigated. The purpose of this study was to evaluate the position of the main occluding area in patients with FPDs quantitatively. We compared the position of the main occluding area between the control subjects who had complete dentition and the patients who wore FPDs for replacing missing first lower molars. Pieces of temporary filling material were used as test material to decide the position of the main occluding area. The centroid coordinate of the test material was calculated and projected onto the reference axis in order to evaluate the position of the main occluding area. Moreover, we recorded the occlusal contact areas at the intercuspal position in order to evaluate the relationship between the position of main occluding area and occlusal contacts.As a result, the position of the main occluding areas in the FPD group were significantly posterior to those in the control group and tended to be less stable. Besides occlusal contact area, existence of periodontal ligaments in the pontic region may cause the difference of the positions of the main occluding area between the FPD group and the control group.
已经明确的是，食物咀嚼是在功能尖之间的限定区域内进行的，即“主要咬合区域”。然而，固定局部义齿（FPD）患者的主要咬合区域位置尚未进行定量研究。在咀嚼早期，根据主要咬合区域的位置，FPD基牙上的负荷有可能过度加载。因此，对FPD的主要咬合区域位置进行了研究。本研究的目的是定量评估FPD患者的主要咬合区域位置。我们比较了全口牙列的对照受试者和佩戴FPD替代缺失的下颌第一磨牙的患者之间主要咬合区域的位置。使用临时填充材料片作为测试材料来确定主要咬合区域的位置。计算测试材料的质心坐标并投影到参考轴上，以评估主要咬合区域的位置。此外，我们记录了牙尖交错位的咬合接触面积，以评估主要咬合区域位置与咬合接触之间的关系。结果，FPD组的主要咬合区域位置明显比对照组靠后，并且趋于不太稳定。除了咬合接触面积外，桥体区域牙周膜的存在可能导致FPD组和对照组之间主要咬合区域位置的差异。
