Accuracy of digital models of full crowns constructed by three types of dental gypsum materials：a comparative study

Abstract:

Objective：To investigate the accuracy of digital models of full crowns which were constructed by three types of dental gypsum materials in Cerec Inlab MC XL system. Methods：A upper first right molar in the standard model was prepared，and eight scanned models made of superhard gypsum，Esthetic-base gypsum，and CAM-base were duplicated respectively. Eight digital models in each group were digitally imaged by scanning in InEos unit with Rotational method（superhard gypsum was scanned after spraying powder）. The distance parameters of each digital model were measured by inlab 3D software（version 3.65） and compared with mate－rial object. Finally，the experimental data were analyzed by SPSS 19.0 statistical software. Results：The quality of digital imaging was better in superhard gypsum group than in Esthetic-base and CAM-base group. The observed values of Esthetic-base group，CAM-base group and the real group had no statistical difference in terms of buccal-lingual（P=0.199），and mesial-distal directions（P=0.087），but the observed values of the superhard gypsum group and real group were statistically different（P=0.000，P=0.003）. In addition，the deviation values of superhard gypsum group were greater in mesial-distal directions than in buccal-lingual directions，with statistical－ly significant differences（F=7.310，P=0.000）. The overall offset of superhard gypsum group，Esthetic-base group and CAM-base group were （0.049±0.036），（0.016±0.050） mm and （0.017±0.052） mm，respectively. Conclusion：Under the condition of this ex－periment，the esthetic-base and CAM-base have high accuracy，but superhard gypsum after spraying powder is not recommended due to its inaccuracy.