全口义齿平面前点确定方法的光弹性研究

Photoelastic study of the method of determining the occlusal plane front point of complete denture

目的探讨全口义齿平面前点的确定方法与光弹性效果。方法选择2015年2月—2017年7月到我院诊治的10例牙列缺失患者作为研究对象,同时制作了由哥特式弓轨迹顶点(义齿A组)、自然咬合法(义齿B组)确定平面前点的全口义齿,测定义齿的咬合指标、光弹性效果与应力情况。结果调前,义齿A组的咬合接触时间多于义齿B组,左右侧力百分比差值与力中心距离到中线的距离少于义齿B组,对比均有统计学意义(P<0.05);调后两组上述指标对比均无统计学意义(P>0.05)。义齿A组与义齿B组测定都显示牙尖工作斜面与平面的夹角呈越向远中越大的趋势,相邻角度差值也有向远中增大的趋势,组间对比无差异(P>0.05)。义齿A组与义齿B组模型的光弹性材料符合模型实验的基本要求,两组的舌向集中的正中与前伸最大应力值均小于解剖(P<0.05),两组对比无统计学差异(P>0.05)。结论采用哥特式弓轨迹顶点与自然咬合法确定全口义齿平面前点能维持义齿平衡,其中哥特式弓轨迹顶点确定平面前点的全口义齿的咬合能达到更好的咬合关系。

Objective To investigate the method of determining the occlusal plane front point of complete denture and the photoelastic effect. Methods The study time was from February 2015 to July 2017. 10 patients with dentition defect diagnosed and treated in our hospital were selected as the research objects. The occlusal plane anterior point of the complete denture was determined by the Gothic arch apex（ A group） and natural trajectory bite（ B group）. The denture occlusal index,photoelastic effect and stress were recorded and detected. Results Before the occlusal adjustment,the occlusal contact time in A group was more than B group,while the percentage difference of occlusal force between left and right sides,the distance from the center of the occlusal force to the center line were less than B denture group,and there was statistical significance（ P〈0. 05）. After occlusal adjustment,the above indexes were compared between the two groups,while there was no statistical significance（ P〉0.05）. The angle between the working angle of the cusp and the occlusal plane in the two group showed tendency of going farther. The adjacent angle difference also had the tendency to increase in the far distance,and there was no significant difference between the two groups（ P〉0.05）. The light elastic materials of A group and B group were all to meet the basic requirements of model experiment. Lingual concentrated jaw centric occlusion and anterior occlusion of two groups were less than the maximum stress value of anatomic occlusal（ P〈0.05）,and there was no difference between the two groups（ P〉0.05）. Conclusion The Gothic arch vertex and natural trajectory bite which determine the occlusal plane anterior point of complete denture can maintain the denture occlusal balance,and the Gothic arch vertex which determines the occlusal plane anterior point can achieve better occlusal relationship.