| Popis: |
Sama A. Suliman: Teeth Dehydration/Rehydration and the effect of time on tooth shade selection (Under the direction of Harald H. Heymann) Objective: The purpose of this clinical study is to estimate the time required for teeth to dehydrate and rehydrate and its relation to the accuracy of tooth shade selection. Materials and Methods: Thirty-two participants were recruited, and color measurements were conducted using a spectrophotometer placed with a custom jig. Measurements were made at baseline, and then after isolation using a lip retractor at 1, 2, 3, 5, 7, 10 and 15 minute intervals to determine tooth dehydration time. After mouth rinsing for 5 minutes measurements were again made at the same interval time to determine tooth rehydration time. The values obtained were used to calculate CIEDE2000 values for color change between the baseline recordings and all intervals. The data were compared to the 50:50% perceptibility and acceptability thresholds and analyzed for the color change over time using ANOVA and Tukey test was used for multiple comparisons. Result: There was a perceivable change in tooth color within the first minute of tooth dehydration (P>0.0001). After the first minute, 87% of the teeth were beyond the ∆E00 perceptibility threshold (0.8), and 72% of the teeth were beyond the ∆E00 acceptability threshold (1.8). After 15 minutes of rehydration, 90% of the teeth were beyond the perceptibility threshold, and 65% were beyond the acceptability threshold. The original shade was not restored for the tested teeth even after 15 minutes of rehydration time. Conclusions: Shade selection procedures should be carried out within the first minute and before the teeth are exposed to dehydration by means of isolation. Teeth do not rehydrate within 15 minutes after rehydration. |
