Tooth shape restoration with template feature line matching

Tooth shape restoration is an essential problem of dental restoration CAD system, in which structural feature lines like cervical margin lines and boundaries of restoration regions are the key elements for guaranteeing the accuracy of dental restorations. In order to solve the problems of existing methods that the morphology of the occlusal surfaces near the structural feature lines are not constrained and only partially missing cases are dealt with, we propose a reconstruction algorithm combining template feature line matching and moving least square (MLS) deformation. Firstly, the structural feature lines lying on the tooth preparation are specified using an intelligent scissor algorithm and projected onto the template tooth model using surface fitting technique to establish curve constraints. Then the template tooth model is aligned to the tooth preparation using as-rigid-as-possible MLS deformation. Finally, we parallelize the implementation of the MLS deformation to support feature line guided real-time interactive design of the occlusal surface. Experimental results show that, thanks to the curve constraints, high quality occlusal surfaces near structural feature lines are obtained.