Clinical effects of dehydration on tooth color: How much and how long?

To evaluate effects of dehydration on tooth color determine whether color returns to baseline after 30 min or 24 h.

Thirty participants with intact maxillary central and lateral incisors were recruited for the study. Color measurements were performed with a spectrophotometer (SpectroShade Micro) at baseline and at 10, 20, and 30 min of dehydration, as well as 30 min and 24 h of rehydration. CIEDE2000 color parameters were used to calculate color difference. The data were analyzed for color changes over time by repeated-measures analysis of variance (ANOVA), and the Bonferroni-Tukey test was used for post-ANOVA comparisons (P < .05).

After 30 min of dehydration, all the tested teeth were above the perceptibility threshold (ΔE₀₀ = 0.8), and 85% of the teeth were above the acceptability threshold (ΔE₀₀ = 1.8). After 30 min of rehydration, 78.3% of the tested teeth were above the perceptibility threshold, and 31.6% of the teeth were above the acceptability threshold. After 24 h of rehydration, 99.2% of the teeth were below the acceptability threshold, and 90% of the values were below the perceptibility threshold.

Thirty-minute tooth dehydration can result in a clinically significant color change. After a 24-h rehydration period, reliable color assessment can be performed.

Tooth dehydration causes significant color change, thus assessment of final color or clinical success should be considered after tooth rehydration for esthetic restorations and tooth bleaching.