Repetition Improves Precision and Trueness of Digital Intraoral Scans

Study Participants: This study was approved by the institutional review board of Ehwa Womans University Medical Center Mokdong Hospital, and dental hygienists who were suitable for the purpose of the study were selected (ECT14-02A-27). Participants were assigned one of four patients, and subsequently scanned the oral cavity of a single patient 10 times repeatedly over 4 days. Study Design: The participants visited the dental clinic and performed scanning for 4 days. In order to investigate the difference in the precision and trueness of two types of intraoral scanners, the participants scanned the dental arch of a single patient 10 times using an assigned digital intraoral scanner. On the first day, either of the two types of scanners (iTero and Trios), and a patient were assigned. Then, the participants were trained in theory and practices of the assigned scanner, and subsequently, using it, scanned the dental arch of the assigned patient twice. On the second and third days, the dental arch of the same patient was scanned 3 times respectively, and on the fourth day, the experiment was finished after scanning the same patient twice. Statistical Analyses: Collected data were analyzed using the SPSS Ver. 20.0 statistical package. For the determination of differences in the deviations according to the scanner, the independent two-sample t-test was conducted to examine the significance of the precision data. For comparisons of trueness according to repeated learning, the repeated measure ANOVA was used to test for differences between the scanners, clinical experience of the participants, and the scanning region within the same scanner group. The significance of time-dependent changes, and the interaction between the scanner group and time variables, were examined by within-subject tests. Differences between the scanner groups were examined by between-subject tests. The significance of the 10 consecutive scans and four visits within the scanner group, and the difference between the scanner groups at each time point, were examined by the post-hoc test, which was performed using the Bonferroni method as a multiple comparison (α= 0.05).