CAD技术在牙齿上下颌模型虚拟对位中的应用

Virtual Orientation of Lower and Upper Jaw Models Using CAD Technology

采用上下颌模型牙尖交错牙合的虚拟对位技术,解决了在口外获取缺牙对颌牙牙合面三维数据的问题。首先通过构造圆柱面上点的高斯图和任意采样的方法,计算出简单牙合架转动轴线方程。然后鉴于牙合面结构的复杂性和非凸性,引入了一种基于图像的快速碰撞检测方法,用于检查上下颌牙齿的对位情况。该方法通过在上颌左右第一磨牙近中舌尖处建立透视视景体,利用O penGL的选择模式,可以实时地检测下颌模型绕牙合架转动轴线旋转过程中与上颌模型碰撞对位情况,效率很高。最终建立了上下颌全牙列牙尖交错位的牙合面间关系,为缺牙牙合面虚拟咬合调整初步奠定了基础。

How to acquire the 3D data of the edentulous opposite occlusal surface outside the mouth is solved by using the virtual orientation of lower and upper jaw models on the position of the intercupided occlusion. Firstly, the Gauss map of points on the cylinder and a random sampling method are used to compute the rotation axis equation of the simple articulator. Considering the complexity and non-convexity of the occlusal surface, a fast collision detection algorithm based on the image space is introduced. By setting two perspective cameras at the first molars of the upper jaw and using the OpenGL selection mode, the real-time collision detection with high efficiency between lower and upper jaws can be realized as the lower jaw rotates around the axis of the articulator. Finally, the occlusal relation between lower and upper jaws on the position of the intercupided occlusion is built. And it provides a primary basis for the virtual adjustment of the edentulous occlusal surface.