解剖型人工牙牙尖斜度的三维测量与分析

The three-dimensional measurements and analysis of anatomic artificial teeth cusp inclination

目的：研究解剖（牙合）型全口义齿人工牙牙尖斜度连续变化特征分析其对全口义齿平衡（牙合）建立的影响。方法：使用光学多自由度扫描仪扫描得到解剖（牙合）型全口义齿人工牙三维数据经逆向工程软件Surfacer 10.5三维建模,测量牙尖斜面牙尖底至牙尖顶连线与牙尖底平面的夹角,代表牙尖工作斜面斜度,并将此连线投影至人工牙（牙合）面得相应曲线,测量曲线斜率的连续变化值,分析牙尖斜面斜度连续变化特征。结果：测得人工牙后牙牙尖斜面斜率及其投影曲线斜率连续变化值。上后牙颊尖远中斜面斜率13.7°-25.6°,下后牙颊尖近中斜面斜率11.3°-37.7°,不同牙齿间差异较大,（牙合）面近中央窝附近表现为斜率迅速升高的突面。结论：解剖（牙合）型全口义齿人工牙牙尖工作斜面斜度不同牙齿间的较大差异及其凸面的形态不利于建立稳定的正中止与非正中（牙合）咀嚼运动的顺畅。

Objective：To survey the continuous change features of cusp angle in anatomic artificial teeth,and to investigate their effects on occlusal balance.Methods：28 artificial teeth of a complete denture were measured by optical three-dimensional（3D） scanner and the corresponding digital models were constructed using the reverse engineering software Surfacer 10.5.The working side cusp slopes of lateroprotrusive movement including the maxillary buccal cusp distal slopes and the mandibular buccal cusp mesial slopes were studied.The straight lines from bottom to top of cusp were constructed and the corresponding projected curves in occlusal surface were generated.The angulation values of straight line and the continuous change values of projected curve were calculated.Results：The angulation values of artificial teeth cusp inclination including straight line and corresponding projected curve were obtained.The maxillary working cusp inclination varied from 13.7° to 25.6°,and the mandibular working cusp inclination varied from 11.3° to 37.7°.Conclusion：The relatively large differences of the cusp inclination among traditional anatomic artificial teeth and the convex form of the cusp are disadvantage factors to set up stable centric stop and unhindered chew course.