부산대학교 도서관

A precision 3-dimensional (3D) head model can be fabricated by integrating laser-scanned dental image into a maxillofacial cone-beam computed tomography (CBCT) image. The purpose of the present study was to examine whether the registration accuracy increases or not in case some visible occlusal surface and incisal edge area were included as registration area in addition to buccal surface in the integration of laser scanned dental image into the maxillofacial CBCT image. The CBCT scans were obtained from 30 adults, and the maxillofacial 3D images were reconstructed. Maxillary dental casts were taken from the same subjects and scanned with a 3D laser scanner. For the integration of laser scanned dental images into maxillofacial CBCT images, all anterior teeth and the second molars were used as the registration area. In order to evaluate the effect of inclusion of some visible occlusal surface and incisal edge as the registration area, three types of implementation were performed according to the area: only the buccal/labial surfaces (R1), the incisal edge of anterior teeth, and buccal and distal marginal ridge of second molars (R2), and labial surfaces including incisal edge of anterior teeth and buccal surfaces including buccal and distal marginal ridge of second molars (R3). Surface-based registration was performed by using an iterative closest point algorithm, and the differences between the two images were evaluated with color-mapping methods and shell/shell deviation by measuring the 3D Euclidean distances between the surface points on the 2 images.1. In the evaluation with color-mapping methods, the R1 method which used facial surfaces only as the registration area showed more discrepancies between the laser scanned and CBCT images than the other two methods.2. The discrepancy occurred on incisal edge and lingual surface of incisors and occlusal surface of posterior teeth indicating that deviation of the two images occurred mostly in occluso-gingival direction.3. Also in the comparison of registration errors by using shell/shell deviation, the R1 method which used facial surfaces only as the registration area showed highest errors than the other two methods.4. The R2 method which used incisal edge and marginal ridge as the registration area did not show a significant difference in registration accuracy with the R3 method which used facial surfaces together with incisal edge and marginal ridge as the registration area.The results of this study indicate that the accuracy in the integration of laser-scanned dental images into the maxillofacial CBCT images can be increased by including some visible occlusal surface and incisal edge area as registration area.