Clinical efficiency of a natural resin fluoride varnish (Shellac F) in reducing dentin hypersensitivity

Previous in vitro permeability and scanning electron microscopic studies have demonstrated the effectiveness of a new natural based-resin varnish (Shellac F) in dentin permeability reduction and effective tubule occlusion. The aim of this randomized double-blind, controlled, split mouth 8-week clinical study was to evaluate the efficiency of Shellac F in reducing dentin hypersensitivity. Ten patients (eight women: two men) completed the study. A quadrant including at least one hypersensitive tooth (Visual Analog Scale - VAS = 15 mm to air blast) was considered as a unit and randomly assigned to different groups for Shellac F, Duraphat, Isodan. Three applications of each material were completed at days 0, 1 and 7. The subjective response was assessed by tactile and thermal/evaporative methods. Data were collected at baseline and after the first application, at 15 min, 1, 7, 14, 28 and 56 days. Analysis was based on Kruskall-Wallis test, Wilcoxon signed rank test and the method of the least square means. No statistically significant difference was noted between Shellac F and the two control materials. Regardless of the type of stimulus, Shellac F showed significant immediate and progressive continuous efficiency in reducing dentin hypersensitivity until 56 days (VAS of 14 +/- 12 mm and provoking pain force of 89 +/- 12 cN, respectively, compared with 38 +/- 23 mm and 41 +/- 10 cN at baseline), corresponding to a highly effective relief dentin hypersensitivity. Shellac F reduced dentin hypersensitivity and did not differ from the two desensitizing agents used as controls.