Effect of new developed home bleaching gel on TOOTH surface roughness, microhardness and color change

This study aimed to evaluate to effects of newly developed experimental bleaching gels containing chitosan and theobromine, BioWhiten ProHome containing 6% HP and FGM Whiteness Perfect home bleaching gels containing 16% KP on tooth surface roughness, microhardness, and color change. Ninety-six upper central incisors were used to measure microhardness and surface roughness. The crown parts of the teeth were separated from the root parts, and each of them was embedded in automatic polymerized acrylic resin. Acrylic blocks were numbered and marked and divided into 2 different groups (n=48). For color analysis, 48 upper central incisors were embedded in silicone impression material, leaving their crowns exposed in groups. Then, each group was divided into subgroups to apply bleaching agents (n=12). Before the bleaching application, surface roughness was measured with a profilometer, microhardness was measured with a Vicker' s test device, and color was measured with a spectrophotometer. An experimental gel containing 16% KP was applied to Group 1, an experimental gel containing 6% HP to Group 2, BioWhiten ProHome containing 6% HP was applied to Group 3, and FGM Whiteness Perfect home bleaching agents containing 16% KP was applied to Group 4. Microhardness and surface roughness tests were performed under the same conditions before and after bleaching and 14 days after the bleaching application. Before the bleaching treatment, during the application (7. days), 24 hours after the treatment, and following 7th and 14th days color analysis was performed. The normal distribution was tested with the Shapiro-Wilk. ANOVA, post-hoc LSD test, Paired t-test were used for normally distributed variables. Kruskal Wallis, Dunn' s tests and Wilcoxon test were used for the non normally distributed variables. p < 0.05 was considered significant. Although there was not a statistically significant increase in the microhardness values after bleaching in all groups.A statistically insignificant decrease was found in all groups in the microhardness values 14 days after the bleaching application (p > 0.05). There was a statistically significant difference between the surface roughness values before and after bleaching and after 14 days of follow-up after the bleaching application in the comparison between the groups (p < 0.05). Effective bleaching was detected in all groups, and the highest efficacy was observed in Group 4 (p < 0.05). As a result, it was determined that the experimental gels containing theobromine and chitosan provided effective bleaching, and did not cause any negative effects on tooth surface roughness and microhardness. Keywords: Hydrogen peroxide, theobromine, chitosan, carbamide peroxide, microhardness, surface roughness, vital bleaching