Influence of pigment solutions with sugar in dental bleaching

The objective was to evaluate, in vitro, the potential of dental pigmentation of beverages with dyes, with or without added sugar, in the bleaching treatment in relation to the visual perception of color change, surface roughness and enamel composition. Seventy-two bovine incisors bovine incisors, recently extracted, free of caries, crack or any enamel defects, were randomly divided into 12 experimental groups formed by the interaction of factors, whitening technique: at-home bleaching (Ca) and in-office bleaching (Co), and solutions: deionized water without sugar (AS), deionized water with sugar (AC), red wine without sugar (VS), red wine with sugar (VC), coffee without sugar (CS) and coffee with sugar (CC). To obtain the samples the crown was separated from the root at 1 mm from the cement-enamel junction and a second cut performed in the distal mesium direction at the height of the pulp chamber. The samples were stored in artificial saliva in an oven with a temperature of 37 ° C. At-home bleaching was performed with 10% carbamide peroxide for 30 consecutive days, remaining in contact with the enamel surface for 2 hours/day, according to the manufacturer's recommendation. For the in-office bleaching technique, 37.5% hydrogen peroxide gel was used, which remained in contact with the enamel surface for 24 minutes in 3 applications of 8 minutes each. A total of 3 treatment sessions were performed, with interval of 7 days between each session. The vestibular surfaces of the samples were subjected daily to the test solutions for 45 minutes, then rinsed with distilled water for 5 minutes and stored again in artificial saliva until the next bleaching or staining session. The enamel color analysis was performed in an objective way, through the use of spectrophotometer and the color variation after bleaching was determined through the parameters color variation (ΔE) and variation of luminosity (ΔL). The roughness analysis was performed by atomic force microscopy (MFA) and by scanning electron microscopy (SEM). The enamel composition was determined by Xray dispersive energy spectrometry (EDS). The results were submitted to analysis of variance (ANOVA) one factor for ΔE and ΔL and two factors for MFA and EDS. For ΔE and ΔL there was no statistically significant difference between the groups tested. The MFA presented a statistical difference in the factors dye solution, bleaching technique and its interaction, corroborating with the images found in SEM. Increased surface roughness of the enamel was observed when water solution with sugar was exposed for home bleaching and other results show that the roughness is dependent on the technical interaction of whitening and solution. In the composition of dental enamel was observed lower concentration of Ca and P in the analysis by EDS in the presence of sugar in the solution of deionized water. Despite the limitations of an in vitro study, we can conclude that the result of tooth whitening is independent of the whitening gel concentration. The presence of sugar in the solution of deionized water increased the surface roughness of the enamel to 10% carbamide peroxide and decreased the concentration of Ca and P in the enamel. (author)