Dentine hypersensitivity and the placebo response

A considerable number of varied agents are apparently effective in the treatment of dentine hypersensitivity. In particular, the literature supports the efficacy of strontium, potassium and fluoride containing toothpastes. This study was a double-blind, randomised, parallel group comparison of three products, namely strontium- and potassium-based desensitising toothpastes both containing fluoride, and a conventional fluoride toothpaste. A total of 131 subjects entered a 4-week wash-in phase using the conventional fluoride toothpaste, of whom 120 entered a 6-week treatment phase. Sensitive teeth were evaluated at wash-in baseline, treatment baseline and after 2 and 6 weeks use of the treatment pastes. Dentine hypersensitivity was assessed with tactile and cold air stimuli together with an overall subjective assessment. Analysis of the findings was performed using non-parametric statistical methods. Of the original 120 subjects, 112 completed the trial. All 3 toothpaste groups showed reductions in sensitivity over the 6 weeks; however, no significant differences were found between the three products at any given time. Interestingly, there was no significant change in sensitivity between wash-in baseline and treatment baseline for the cold air stimulus with the fluoride-only-based paste. However, for the group using the same fluoride toothpaste, there was significant improvement between wash-in baseline and week 6, and treatment baseline and week 6 for this stimulus, suggesting a substantial placebo effect occurred. There is a need for further investigation of a wash-in period and examination of the placebo effect when evaluating dentine hypersensitivity trials.