Efficacy of an experimental 3% potassium nitrate mouthwash in providing long-term relief from dentin hypersensitivity: An 8-week randomized controlled study (Study 2).

Purpose: To evaluate the efficacy of an experimental mouthwash containing 3% potassium nitrate (KNO3) in the relief of dentin hypersensitivity when used as an adjunct to brushing with fluoride toothpaste compared with the use of the same toothpaste alone.

Methods: This was a randomized, two-treatment, examiner-blind, parallel-design single-center, 8-week study in healthy subjects with self-reported and clinically diagnosed dentin hypersensitivity. Subjects were randomized to receive either fluoride toothpaste plus 3.0% KNO₂ mouthwash or the same fluoride toothpaste alone, and instructed to use their allocated treatment twice daily for the next 8 weeks. Dentin hypersensitivity was evaluated at baseline and following 4 and 8 weeks of treatment through assessment of responses to evaporative (air) and tactile stimuli [measured by the Schiff sensitivity scale/a visual rating scale (VRS) and tactile threshold, respectively], and using the Dentin Hypersensitivity Experience Questionnaire (DHEQ, a validated quality-of-life instrument for dentin hyper-sensitivity).

Results: A total of 135 subjects were randomized and all completed the study. Both treatment groups demonstrated statistically significant improvements in sensitivity from baseline for each clinical measure of sensitivity (P< 0.0001) at Week 4 and Week 8. The toothpaste plus mouthwash group showed greater reductions in sensitivity at both timepoints for all clinical measures; between-treatment differences were only statistically significant for responses to an evaporative (air) stimulus (Schiff sensitivity score and VRS) at Week 4. There was evidence of an improvement in dentin hypersensitivity-associated quality of life as measured by changes from baseline in several DHEQ parameters for both treatment groups, but there were no statistically significant differences between treatments.

Clinical Significance: Although in the current study adjunctive use of a 3% KNO₂ mouthwash did not provide statistically significant improvements in dentin hypersensitivity for all clinical measures at all timepoints compared with use of fluoride toothpaste alone, the reductions in sensitivity observed in this study are compatible with the findings of a previous study that showed adjunctive use of a 3% KNO₂ mouthwash to be effective in providing relief from dentin hypersensitivity after 8 weeks' twice-daily use.