Effect of two desensitizing agents applied previous to in-office bleaching on the degree of whitening and dentin sensitivity: A randomized, controlled, double-blind clinical trial.

Purpose: To evaluate the effect of two desensitizing agents applied before in-office bleaching, on the degree of whitening and dentin sensitivity.

Methods: Participants were randomly assigned to the groups, according to the desensitizing agent used, with n=10 for each one. The bleaching was performed with 35% hydrogen peroxide, divided according to the desensitizing agent used prior to the bleaching procedure: Placebo (PL); Desensibilize KF with potassium nitrate and 0.2% sodium fluoride (PN); and Oxa-Gel with potassium oxalate (PO). The level of color saturation was assessed at the beginning of treatment and after 1 week of its completion by means of comparative method with the aid of a color scale. The degree of sensitivity (DS) was noted by the subjects with the aid of a visual scale throughout the time that the bleaching agent remained in contact with the teeth (5, 10, 15, 20, 25 and 30 minutes) as well as 1, 24 and 48 hours after the end of application. Pain and the degree of color saturation were evaluated using the Shapiro-Wilk test. The DS was assessed by Kruskal-Wallis and Dunn's tests. The color was evaluated by ANOVA and Tukey's HSD.

Results: There was no significant difference in the degree of bleaching among the groups. DS was significantly more accentuated in the 48-hour period. The DS was significantly higher for the PL group and significantly lower for the PO group. The desensitizing agents reduced the DS without affecting the effectiveness of the bleaching treatment.

Clinical Significance: Both desensitizing agents provided greater control over pain compared to the placebo group. Potassium oxalate showed greater pain control than potassium nitrate. Both desensitizing agents tested did not interfere in the degree of whitening.