Construction of three-dimensional human tooth models - Abnormal tooth models -

Objectives:To construct three-dimensional human tooth databases available to everyone, the authors produced three-dimensional models of 35 human teeth and 52 carious teeth extracted during treatment. These models facilitated the three-dimensional understanding of the tooth morphology, progression of dental caries, and conditions of actual dental pulp, being useful for student practice and as a new study method. In this study, we produced three-dimensional models of 120 abnormal teeth from Japanese which have been collected and preserved in Matsumoto Dental University.

Methods:X-ray images of 120 abnormal teeth were taken using a three-dimensional micro-CT (R-mCT, Rigaku). Data obtained were reconstructed, and tomograms (500 x 500 pixels) were produced at intervals of 50 ƒÝm using i-View (Morita). After removing artifacts from approximately 60,000 tomograms using Photoshop (Adobe), visualization was performed using a Micro-AVS (KGT).

Results:Although stripes frequently appeared in the three-dimensional models, evaluation using aluminum cubes revealed that these were due to numerical errors occurring at the time of the correction of inclination using i-View. These numerical errors are inevitable because of its principle; therefore, attention should be paid to the understanding of clinical images. As a result of reconstructing all images without inclination correction, the stripes were removed.

Conclusion:It took 35 years to collect these 120 abnormal teeth; therefore, they are very precious. However, since each sample comprises only one actual human tooth, students do not have enough opportunities to observe them. However, by the use of the models developed in this study, it becomes possible for thousands of students to simultaneously observe them at any time. Furthermore, it is also possible to observe the internal structure of cross-sectioned surfaces, without having to destroy precious specimens. Therefore, the models are useful for education, and may become a method to study the genetic processes leading to abnormal teeth.