Construction of 3-D Shape of Orthodontic Dental Casts Measured from Two Directions

To obtain full 3-D shape data of a orthodontic dental cast, high-speed measuring equipment with a line laser and a precise goniometer were used, and a program to connect the measured data was developed. Initially, the accuracy of the equipment and the goniometer was examined and confirmed to be suitable for clinical use.Two upper dental casts with and without crowding in the anterior segment were measured from two directions, i.e. the occlusal and labial sides, and the occlusal data were connected by an original program to the labial data at a boundary point with the largest Z-diff, which showed the largest difference in the height (Z) direction between the two neighboring data.The proposed algorithm to find the largest Z-diff was confirmed to work effectively in both casts, and the entire 3-D data of the casts was acquired satisfactorily except for the labial surfaces of the lateral incisors which were not measured from either direction on the cast with severe crowding.