抄録
Introduction:
Nowadays, three-dimensionally reconstructed virtual dental model is widely used for various purposes. It can express tooth as a cloud of points which have unique coordinate values. Complex and sophisticated measurements and mathematical calculations, which are impossible with conventional models, can be made on these virtual models. The aim of this study is making average tooth form of Korean which must be different with other races.
Materials and Methods:
Dental cast sets were prepared from 100 students. Casts were scanned and reconstructed three-dimensionally using Rapidform software. First molar of both arches were isolated from virtual dental arch for making average teeth forms. After curvature and volume based alignment, the 200 slice curves were generated according to customized planes of samples. All curves of all samples were uniformly tessellated. Average points were calculated through tessellated points of all samples and reconstructed as polygonal three-dimensional models.
Because there are no standards for the average teeth forms, we compared the distances between specific landmarks of both average forms and average of each tooth form before alignment.
Results:
Using developed algorithm, average forms of maxillary and mandibular first molar were made (Fig. 1). They showed smooth line angles because of limitations of the number of points and a large number of samples. Distance discrepancy of landmarks between average tooth form and each tooth form before alignment was very small ranged from 0.03 mm to 0.35 mm.
Discussion:
Until now, gold casting is the most popular material and technique for the restoration of molars. However, new materials for milling technique are coming out rapidly and used in laboratory. This study would support milling technique through providing tooth template which can be expressed as 3-dimensional coordinates system. We expect that another virtual average tooth form for other races could be also constructed using this algorithm.
Conclusions:
Average teeth form could be used as a mold of resin tooth for denture. It will be also applied as a basic form for missing tooth reconstruction with the combining of CAD system. Another sophisticated algorithm will be developed in the near future for these purposes.
