Three-dimensional occlusal and interproximal contact detection and display using virtual tooth models

A method of monitoring toot wear, comprising the steps of:

• 1) obtaining a first three-dimensional virtual model of a portion of the patient's dentition at a first point in time, wherein said first virtual model comprises a virtual model of the upper and lower arches;
• 2) obtainig a second three-dimensional virtual model of said portion of the patient's dentition at a second, later point in time;
• wherein said second virtual model comprises a virtual model of the upper and lower arches;
• 3) determining occlusal contact areas of said upper and lower arches for said first three-dimensional model;
• 4) determining occlusal contact areas of said upper and lower arches for said second three-dimensional model;
• wherein in steps 3) and 4) determining said occlusal contact areas comprises:
• a) calculating, with said three-dimensional virtual model of a portion of the patient's dentition, distances characterizing the occlusal relationship between surfaces of teeth in one of said upper and lower arches and surfaces of teeth in the other of said upper and lower arches when said arches are in an occluded condition;
• wherein said step of calculating includes, for a plurality of points on a surface of a tooth, the step of calculating a sphere around each of said points, and enlarging the size of the sphere until the sphere intersects with a surface of a tooth on the opposing arch in said model;
• and
• whereby a comparison of said occlusal contact areas from step 4) with said occlusal contact areas of step 3) provides an indication of tooth wear with an increase in occlusal contact area indicating tooth wear.