Use of an ultrahigh-speed laser scanner for constructing three-dimensionalshapes of dentition and occlusion

Statement of problem. Acquisition of the 3-dimensional shape of dental cast s is useful for quantitative evaluation of the diagnosis and treatment of o cclusion. Purpose. This study demonstrated the acquisition of data through the use of an ultrahigh-speed laser scanner and an originally developed goniometer, t he use of these tools to measure the entire 3-dimensional shape of the dent al cast from multiple directions, and the connection of the data measuremen ts to reconstruct the cast's occlusion with the use of a computer. Material and methods. A commercially available apparatus that emits a line laser and completes 1 scan in only 0.6 seconds was used. To compensate for the unmeasured region, the cast was measured from 4 directions on the origi nal goniometer, and the connection of data to obtain the entire image was c arried out. Further, the reconstruction of the occlusion between the upper and lower casts was attempted by transferring the upper cast data to the lo wer cast. Results. By the data connection, the entire shape of the upper and lower ca sts was constructed, and the characteristic structure was reproduced. The d ata connections were satisfactory for the flat surfaces but less accurate f or the inclined surfaces. Reconstruction of the occlusion between the upper and lower casts was accomplished. It was then possible to visualize the oc clusion from arbitrary directions and sections with computer graphics. Conclusion. The construction of the entire 3-dimensional shape of a dental cast and the reconstruction of the occlusion were accomplished using an ult rahigh-speed measurement system and original goniometer. These results will be useful for clinical applications such as computerized diagnoses and tre atment of occlusion, and for the replacement of the stent casts in the dent al office by computerized data.