Comparison of the morphological accuracy of automatic crowns designed by multiple computer-aided design software programs with different levels of dentition information acquisition.

STATEMENT OF PROBLEM:Information on the morphological accuracy of crowns automatically produced by different computer-aided design (CAD) software programs for multilevel dentition defects is limited. PURPOSE:The purpose of this in vitro study was to compare the morphological accuracy of crowns fabricated using different CAD software programs with different design theories for multilevel dentition defects. MATERIAL AND METHODS:Four dentition defect types (the standard group, the abrasion group, the adjacent-teeth-missing group, and the antagonist-tooth-missing group, n=10) were fabricated to represent different levels of missing dentition information. Two design modes (the library mode and correlation mode) of 3 common CAD software programs (3Shape [3Shape Dental system], CEREC [Dentsply Sirona], and exocad DentalCAD [exocad GmbH]) were used to design crowns automatically, and the morphologies of the generated crowns and original teeth were recorded. The root mean square (RMS) value was calculated to evaluate the morphological deviations between the autogenerated crowns and original teeth using the 3D matching system (Geomagic GmbH). As each group in this study represented 3 factors, the mean differences between the treatment combinations and the interaction effects were analyzed by performing factorial analysis of variance (α=.05). RESULTS:The RMS values of autogenerated crowns designed using the correlation method were significantly lower than those designed using the library method of each software program in the 4 groups (P<.05). The RMS values of crowns designed by the 3Shape and CEREC software programs in library mode under conditions with dentition information loss were lower than those of crowns designed by the exocad software program (P<.05). Changes in the acquisition of dental information did not decrease the CEREC design accuracy (P>.05), while they did decrease the 3Shape and exocad design accuracy (P<.05). CONCLUSIONS:The correlation method showed higher accuracy in rebuilding the original morphology of the teeth than the library method. Both the 3Shape and CEREC software programs showed higher accuracy than the exocad software program in library mode under conditions with dentition information loss, while CEREC showed higher stability than the 3Shape and exocad software programs.