Abstract: PURPOSE: To analyze the accuracy of three-dimensional model teeth of three different materials by using oral digital impression instrument combined with Mimics 19.0 software, and compare their physical and chemical properties, economic characteristics and clinical application characteristics. METHODS: A questionnaire survey was conducted among doctors who carried out autotransplantation of tooth to determine their understanding of different donor model materials, and then the material performance, technological performance, economy and environmental coordination of each model tooth were compared and analyzed. A total of 20 fully extracted third molars were collected, and three-dimensional teeth models of polylactic acid, photosensitive resin and cobalt-chromium alloy were made according to preoperative CBCT data. The isolated teeth and model teeth of various materials were scanned by oral digital impression instrument, and the data were best fitted and analyzed by Mimics 19.0 software. The root mean square(RMS) error was statistically analyzed to make clear the difference in accuracy. SPSS 22.0 software package was used to analyze the data. RESULTS: The results of questionnaire showed that 95.2% of the dentists thought that the donor tooth model was very useful and often used in autotransplantation of tooth, and 90.5% of the dentists thought that the cost of materials and non-toxic and pollution-free were the most important. There was no significant difference between the RMS values of the model teeth and the third molars of the three commonly used materials, the three kinds of materials had mature processing technology, good technological properties and good use performance, among which polylactic acid had low price, biodegradability and low operation risk, while photosensitive resin had medium price, but its manufacturing process might produce toxic substances with high operation risk. Cobalt-chromium alloy was resistant to high temperature and high pressure, but the printing cycle was relatively long and the cost was high. CONCLUSIONS: There is no significant difference in three-dimensional accuracy of polylactic acid, photosensitive resin and cobalt-chromium alloy, but combining the various characteristics of the three kinds of materials, polylactic acid has high performance-to-price ratio and is worthy of clinical application.

Key words: Donor tooth model, 3D printing material, 3D printing technology, 3D accuracy