Abstract: PURPOSE: The goal of this study was to get some sections of a dental cast in the mouth and combine them through computer to get the whole image of the dental cast, then test the accuracy and feasibility of the new method. METHODS: The bite tray impressions of the sections of 10 dental casts were obtained and the impressions were scanned by computer. All the digital image data from three-dimensional optical scanning of a dental cast were combined to get the whole image of the dental cast. The image was used to compare with the dental cast to determine the accuracy. The data were analyzed using SPSS 21.0 software package. RESULTS: The new method to get the whole image of the dental cast by combining the 3D-scanned digital image data through computer was successfully established. By comparing the combined model with initial model, the smallest error observed was (0.046±0.055) mm and the biggest error observed was (0.032±0.115) mm. No significant difference between 3 methods was observed (P>0.05). CONCLUSIONS: The accuracy of dental cast can be obtained by combination of the images of sections of the dental cast through computer. This method can solve the problem in patients who have restriction of mouth opening and difficulty to get the whole dental cast.

Key words: Limitation of mouth opening, Sectional model, Computer aided design, Dental cast