A Comparison of the Accuracy of Intra-oral Scanners Using an Intra-oral Environment Simulator

Abstract

Introduction: The aim of this study was to develop an intra-oral environment simulator and to assess the accuracy of two intra-oral scanners according to the intra-oral environment. Methods: A box-shaped intra-oral environment simulator was designed to simulate specific intra-oral environments with regard to temperature (℃), relative humidity (% RH) and illumination (lux). Two environmental groups were designed based on normal and maximum temperature, humidity, and illumination: 19-21℃/40% RH/262-272 lux and 29-31℃/100% RH/173-197 lux. A dental cast was used to simulate two clinical scenarios. The dental cast was scanned 10 times by Identica Blue (MEDIT, Seoul, South Korea), TRIOS (3Shape, Copenhagen, Denmark), and CS3500 (Carestream Dental, Georgia, United States) scanners in the two environmental groups. After aligning the scanned data with Rapidform 2004 software (INUS Technology, Seoul, South Korea), the distances between the left and right canines (D3), first molars (D6), second molars (D7), and the left canine and left second molar (D37) were measured. The distance were analyzed by the Kruskal-Wallis test. Results: The differences in intra-oral environments were not statistically significant (p > 0.05). Between intra-oral scanners, statistically significant differences (p < 0.05) were revealed by the Kruskal-Wallis test with regard to D3 and D6. TRIOS exhibited higher accuracy similarity to Identica than CS 3500. The value of the standard deviations to assess the reproducibility of the scanners was higher in the CS 3500 than the other scanners. Conclusions: Although a difference of accuracy based on the type of scanners existed, no difference due to the intra-oral environment was revealed. This suggests that the TRIOS and CS 3500 scanners are relatively accurate. Within the limits of the present study to simulate intra-oral environments, the intra-oral simulator that was developed for this study will contribute to the higher accuracy of intra-oral scanners in the future.