Visualizing Occlusal Contact Points Using Laser Surface Dental Scans

Abstract

In dentistry, teeth occlusion is the best possible fit between the maxilla (upper teeth) and the mandible (lower teeth). Understanding occlusion is important for diagnosis, prognosis and treatment of occlusal dysfunction and for planning of reconstructive surgery. Teeth occlusion can be determined by a set of occlusal contact points. Due to the complex surface morphology of the maxilla and mandible, identification and localizing this set of contacts, even to the dentist, is not a trivial task. The visualization of occlusal contact points has important significance in providing the dentist a clear picture of the exact locations of these points, which are important in clinical practice when the dentist wishes to recover or maintain a perfect occlusal balance between the maxilla and mandible. This paper presents a method of determining the set of contact points and visualizing them in 3D. We assume that optimal teeth occlusion has been previously obtained. The contacts points are determined by analyzing the difference image between the maxilla and mandible height fields. With a suitable threshold, one can obtain multiple connected contact regions on the difference image. We can further prune the contact points by searching for local minima using an 8-connectivity neighborhood kernel. We then back-project using ray-casting techniques to obtain a pair of contact correspondence for each point. Visualization results are further enhanced by properly positioning the maxilla and mandible models in 3D and joining the contact points by a set of lines.