Effectiveness of a desensitizing agent before in-office tooth bleaching in restored teeth

The aim of this clinical trial was to evaluate the effectiveness and tooth sensitivity associated with bleaching in patients with composite restorations in anterior teeth after the application of a desensitizing agent.

Bleaching was performed with 35 % hydrogen peroxide gel in 30 patients with composite restorations in anterior teeth, divided according to the prior application of a desensitizing agent (De), or a placebo (Pl), on maxillary superior teeth. Color was recorded at baseline, 1 week after each session and 6 months after treatment. The experience of tooth sensitivity (TS) was recorded on an NRS (0-4) during bleaching and 24 h after each session. Bleaching effectiveness was evaluated by one-way ANOVA and Tukey's tests (α = 0.05). The percentage of TS was evaluated by Fisher's exact test. For each treatment, periods were compared using the Wilcoxon signed-rank test (α = 0.05), and at each period, treatments were compared using Mann-Whitney U test.

Both groups showed similar tooth color enhancement and color stability after 6 months (p < 0.05). No significant difference in prevalence of sensitivity was detected between groups (p < 0.001). Higher TS intensity (median [first/third quartiles]) was observed for Pl (1.5 [1/1.75]) compared with De (0.5 [0/1]) during treatment (p < 0.05).

The use of a desensitizing gel (5 % potassium nitrate, 2 % sodium fluoride) before tooth bleaching in patients with composite restorations did not reduce the prevalence of tooth sensitivity, but reduced the intensity of TS during bleaching.

Although the use of a desensitizing agent before bleaching, in patients with composite resin restorations, did not reduce the prevalence of TS, a reduction of the TS intensity during the protocol was observed without jeopardizing the whitening outcome.