Accuracy and Reliability of Intraoral Scanners for Tooth Shade Determination in Comparisons with Intraoral Spectrophotometer: In Vitro Study

Abstract This study aimed to compare the accuracy and repeatability of shade determination using an intraoral spectrophotometer (SP) and two intraoral scanners, hypothesizing no significant differences in performance. A computer-aided design/computer-aided manufacturing-designed right upper central incisor was manufactured in multiple shades using feldspathic ceramic. Shade determination was performed using the CEREC Primescan (CP), Trios V scanners, and an intraoral SP, with multiple scans taken for each. Measurement accuracy was evaluated using the Cochran Q test and pairwise comparisons with Bonferroni's correction. Reliability was assessed through Cronbach's α, with a significance level set at 0.05 for all tests. The SP achieved 84% accuracy, while the CP and 3Shape Trios V (T5) recorded 66 and 71%, respectively. None of the instruments reached 100% accuracy, with the SP displaying an accuracy range of 80 to 90%, and both scanners achieving between 60 and 80%. Statistically significant differences indicated that the SP outperformed the scanners (p < 0.05). False shade readings showed shades 3M2 and 4M2 as having the highest erroneous results. Reliability scores ranged from 92% for the scanners to 94% for the SP, with a Cronbach's α coefficient of 0.839, indicating high reliability. Intraoral SP displayed superior accuracy over the intraoral scanners, while their reliability in shade assessment was comparable. Thus, dental SPs are preferred for precise shade matching, suggesting potential reliability issues with intraoral scanners for consistent dental shade assessment.