Patient-Specific Mandibular Contact Surface Quad Mesh Generation using B-Splines

Abstract

With the development and maturation of computer graphics in the medical field, the combination of CAD/CAE technology and CT reconstruction technology has gradually infiltrated into various medical research areas in recent years. Human's jaw bones have complex shapes and irregularities. It is thus challenging to do orthodontics treatment through only theoretical analysis. Moreover, dental diagnosis and treatment require accurate simulation of the jaw movement. In this work, we apply the CAD/CAE technology to CT human medical data so as to accurately perform 3D simulation and analyse human's mandibular movement.

In computer graphics, polygonal meshes are popular representation for geometry modeling. While triangle meshes have been used in many geometric modeling applications, quad meshes have better performance in collision detection with its regular structure. Furthermore, they have been successfully used in many applications such as surface analysis, simplification, adaptive refinement, feature alignment, parameterization, and re-meshing. In this thesis, we propose a quad mesh generation method for patient-specific mandibular movement contact surface and assist the simulation of mandibular movement.

First of all, from patient's medical skull CT data, triangle mesh models are generated. For this purpose, we use image processing technology to improve the quality of CT data, and extract the triangular mesh model of the contact part in mandibular movement(Temporomandibular Joint (TMJ) head, Tubercle, and Fossa). Using these triangle mesh models, we construct B-spline quad mesh approximate the generated models. Here we choose a sweep surface method, and slice each model into several pieces, and then calculate the intersection points between mesh data and the slicing plane. Finally, we approximate the intersection points with B-spline curves and merge them to generate a B-spline surface. The final quad mesh is then applied to the analysis of mandibular movement. Overall, the B-spline quad meshes not only compress the original triangular meshes, but also the regular structure makes collision detection more efficient.