Effect of Tooth Brushing on Enamel Surface Roughness and Brightness After 25% Hydrogen Peroxide (HP) Whitening: An In-Vitro Study

Objectives: The aim of this study is to investigate if tooth brushing has an effect on surface roughness and dental brightness after whitening. Materials and Methods: Five healthy random premolars were used repeatedly to minimize inter-sample variability. They were firstly prepared following ISO 28399 guidelines and thereafter they were whitened using an office product containing 25% Hydrogen Peroxide (HP). Afterward, they were subjected to four sessions of brushing. Both Roughness Ra and Rz were measured at each stage of the study using a mechanical contact profilometer. Similarly, luminance was estimated by recording the voltage ‘reflected’ from the teeth using an experimental setup that we designed. Results: Surface Roughness Ra remained stable with no significant differences among the groups (p>0.05). However, Rz values generally increased with significant difference among different groups (p<0.05). The generated voltage increased after teeth whitening, remained stable after the brushing sessions and decreased slightly after one month of brushing, with significant differences only between the control group and the other groups (p<0.05). Conclusion: Tooth brushing after whitening increased the enamel surface roughness. This is likely due to abrasion and microstructural deformations. However, brightness did not evaluate as we expected. It remained stable potentially because of dehydration or optical saturation. This emphasizes the need for further investigations under clinically relevant conditions.