Objectives: To evaluate the reliability and accuracy of spectrophotometric shade determination of premolars and to compare the results with those for incisors.
Material and methods: Fifty-seven participants with natural maxillary incisors and premolars were recruited to investigate the research question. The colour of test teeth (incisors, n = 210; premolars, n = 192) was measured by use of the Vita Easyshade Advance (ES-A) and Vita Easyshade V (ES-V). Accuracy was evaluated by rating the shade tab matches recommended by the devices (scale, 1 = excellent match to 3 = mismatch). Inter-device reliability between the ES-A and ES-V for measurement of incisors and premolars was evaluated using intra-class correlation coefficients (ICC). The ratings for the accuracy of the devices were analysed using descriptive and bivariate statistics. A linear regression model was used to evaluate possible independent influencing confounders on the shade match.
Results: Inter-device agreement of the ES-A and ES-V for measurement of incisors and premolars was excellent for all colour components (ICC > 0.9). The accuracy of both devices was acceptable to excellent for incisors and premolars, although the ES-V was more accurate than the ES-A (p < 0.001). No significant difference in accuracy was detected between premolars and incisors (p = 0.182). The linear regression model confirmed the bivariate testing.
Conclusions: The reliability and accuracy of spectrophotometric shade determination seem comparable for incisors and premolars. The recently introduced ES-V seems more accurate than its predecessor model. Further studies are needed to validate the results of this study.
Keywords: Easyshade; L* a* b*; Premolars; Spectrophotometer; Tooth shade determination.