Influence of Desensitizing on Enamel Colour and Morphology in Association with Bleaching - An In-vitro Study

Desensitizing agents are commonly used to minimize dentin hypersensitivity caused by tooth whitening procedures. The objective was to evaluate the evolution of enamel colour and porosity after home-use tooth whitening with and without a desensitizing agent.

Individual trays with different concentrations of hydrogen peroxide (HP) or carbamide peroxide (CP) bleaching agents were tested with and without prior use of a desensitizing agent. Whitening efficacy was evaluated by spectrophotometer, and the enamel surface alteration was examined by scanning electron microscope. The one-way ANOVA followed by Tukey's post hoc test was used to assess differences in the colour variations among the groups, independently for the middle third, cervical third, and grouped thirds. The paired t-test was used to assess the differences in colour variation between the middle third and the cervical third, independently for each of the groups.

The analysis of colour variation (ΔE) showed that there was no statistical difference among the groups with or without application of a desensitizer (P > 0.05). The change in enamel morphology was proportional to the concentration of the bleaching agent. The microscopy images obtained from the groups using a desensitizer prior to the bleaching agent were similar to those of the groups in which the bleaching agent was used alone.

The association of home bleaching agents with a desensitizing agent did not influence the final result of the bleaching procedure.