The effects of dehydration on color change in natural teeth caused by dental procedures

This study examines the effects of several clinical procedures that lead to dehydration on color change in natural teeth. CIE L*, a*, and b* color coordinates of maxillary incisors were measured using a spectrophotometer before and after the procedure at minute intervals of 10, 20, 30, and 1440 (24 hours). Test groups were as follows: 6 and 15 minutes of the open mouth under LED and halogen dental reflectors; control groups were evaluated in a dark environment for 6 and 15 minutes; maxillary impressions were taken with condensation and additional type impression materials. Wilcoxon signed-rank tests and Mann–Whitney U tests were used for two-group comparisons. The analyses were computed by the Friedman and Kruskal–Wallis H tests for the paired and independent groups. These tests were followed by Bonferroni posthoc corrections. Obtained color values indicate significant L* changes for all groups due to dehydration for 20 minutes after the procedure. Color changes (ΔE) were significant for 30 minutes for the perceptibility (1.2>ΔE) and 20 minutes for the acceptability threshold (2.7>ΔE). Results show that experimental protocols designed to mimic dental procedures that require mouth opening may cause temporary discoloration of natural teeth, which may cause failure during shade matching.