Digital Dental Model Prototype System

In orthodontics, teeth model can help dentists to diagnose, design and measure patients'difference before and after treatments. Three-dimensional digital teeth models overcome shortcomings of traditional plaster model, such as mass storage, frangibility, difficulty of communicating at a long distance and so on. So, there will be a growing demand for digital dental model techniques in orthodontics.In this paper, we design and develop a digital dental model prototype system. We improve some mesh segmentation algorithms, implement intelligent segmentation of teeth mesh models, and make the system applicable in orthodontics. By means of semiautomatic user interaction, dentists are able to separate gingiva and crown quickly and accurately. Our system can help dentists to get insight of teeth structures and to make further orthodontics remedial plans and treatments.The system supports import and export of mesh models in various formats, and organizes teeth model hierarchically. Because of some kind of chaos caused by separated parts of segmentation, hierarchical structure helps establish the hierarchy relationships between models, separated gum and dental crown parts. This makes a solid foundation for system extension, such as computer-aided teeth lifting and feasibility analysis tools.The most important technical basis of orthodontics is three dimensional tooth reconstructions. The system provides a fast and accurate semiautomatic segmentation pipeline. It implements Easy Mesh Cutting algorithm which is based on region growing method. Mesh simplification is introduced to speed up mesh segmentation. This paper adopts snake algorithm to smooth the rough boundaries after segmentation. In addition, users can modify segmentation results by adding or removing the defined meshes manually.Comply with the object oriented design principles, the system adopts MVC framework in which each module works independently and meets "high cohesion and low coupling" criteria. The system provides functionalities including three-dimensional teeth model reconstruction, semiautomatic user interface and digital teeth model management. The system has a good extensibility mechanics that provides a feasible framework for developing further modules and tools.Finally, this paper presents the results of mesh segmentation on teeth and some other general meshes, indicating the accuracy and quickness of the algorithms used in our system. The processing procedure of teeth models in actual cases verifies the validation of the system.