Abstract: Objective To evaluate the influence of tooth position and retention depth of the dental pulp cavity on the accuracy of intraoral digital impression of endocrown preparation. Methods Dental pulp cavities with retention depths of 2, 3, 4 and 5 mm were prepared on 8 auatomic resin tooth models, including 4 right maxillary first molar (16) and 4 right mandibular first molar (46). Each cavity were scanned for 10 times using 3shape trios3, with micro-CT scans as the reference. All the scan data were exported, and the reference models were obtained by 3D reconstruction with Mimics 2021 software. Gomagic Wrap 2017 was used to analyze the 3D models. The average absolute deviation values were calculated to evaluate the accuracy of the digital models. Results There was no significant difference in the authenticity and precision between models 16 and 46. The mean maximum positive and negative deviations of the model 16 were less than those of the model 46 (P<0.05), and for both the models 16 and 46, the mean maximum positive deviation was significantly greater than the mean maximum negative deviation (P<0.05). The authenticity of the 5 mm group was lower than that of the 2 mm, 3 mm and 4 mm groups (P<0.05). The precision was higher in 2 mm group than in 4 mm and 5 mm groups (P<0.05), and higher in 3 mm group than in 5 mm group (P<0.05). The mean maximum positive and negative deviations in 2 mm group were lower than those in 5 mm group (P<0.05). Conclusion The position of teeth has little influence on intraoral digital impression of the endocrown. The retention depth of the dental pulp cavity affects the accuracy of intraoral digital impression of the endocrown, and a greater depth results in a greater deviation.

Key words: endocrown; digital impressions; pulp retention form; micro-CT