Materials and Methods: Extracted human molars were collected, cleaned, and stored in 0.1% Thymol solution. Teeth were sectioned at the amelocemental junction, the coronal and radicular portion was used for the enamel and dentin specimens respectively and randomly assigned to five groups (n=6; see table). A contact profilometer (Mitutoyo Surftest, SV-2000; Andover, UK) was used to measure surface roughness before and after bleaching treatments following manufacturer’s instructions. Measurements were made along the X-axis with a preset evaluation length of 4 mm, and three scans conducted from >100z-values across the scan as calculated by Surfpak-SJ Version 1.600. Roughness changes were determined by the difference between baseline and post-treatment values. Repeated measures ANOVA was used to evaluate within and between-group effects. Post hoc comparisons were conducted with Bonferroni multiple comparisons. Analysis was performed at a 5% significance level.
Results: There were no statistical differences in surface roughness changes for enamel and dentin among groups A to D. Group E demonstrated significant increase in mean surface roughness of the enamel and dentin (p<0.01, p<0.001 respectively).
Group |
Treatment |
Enamel (Ra±SD) |
Dentin (Ra±SD) |
A |
Negative Control: water of grade 3, 35°C, 60-min |
-0.0048±0.0075 |
0.0000±0.0032 |
B |
Zoom DayWhite 9.5% H2O2 (Philips Oral Healthcare, Bothell, WA) |
-0.0020±0.0053 |
0.0016±0.0043 |
C |
Zoom DayWhite 14% H2O2 (Philips Oral Healthcare, Bothell, WA) |
-0.0011±0.0049 |
-0.0011±0.0049 |
D |
Zoom NiteWhite 22% CP (Philips Oral Healthcare, Bothell, WA) |
0.0063±0.0056 |
0.0011±0.0031 |
E |
Positive Control: 1.0% citric acid, 35°C, 60-min |
0.0161±0.0220 |
0.0781±0.0144 |
Conclusions: The bleaching gels tested didn’t affect enamel and dentin surface roughness as evaluated using the method specified by ISO 28399.
Disclosure: The study was supported by a grant from Philips Oral Healthcare.