Abstract: Objective： To evaluate the efficacy of the 45S5 bioactive glass on the reduction of hypersensitivity of teeth prepared for full coverage crowns. Methods: In the study, 31 prepared abutment teeth with vital pulp from 18 patients satisfied the inclusion criteria and exclusion criteria. The patients were informed consent and recruited into the study. This was a before and after self-control, single blind clinical trial. The severity of tooth hypersensitivity at baseline was evaluated, after application of the placebo, which was the powder of zinc oxide, and after application of the 45S5 bioactive glass on the same tooth. Tooth hypersensitivity was evaluated by Yeaple probe and visual analogue scale (VAS) when the tooth was stimulated by a fixed value of mechanical pressure and a blast of cold air respectively. And the dentist gave the subjective score, and the Schiff score at the same time. The three methods of measurement were repeated at baseline, after application of placebo and after application of the powder of 45S5 bioactive glass. Student’s t test and nonparametric test were used for statistical analysis. Results: The indexes measured at baseline, after the application of the placebo and after the application of the 45S5 bioactive glass were as follows, respectively: Tactile value (29.03±9.44) g, (29.68±9.48) g and (44.19±11.19) g, VAS value (50.79±22.92) mm, (46.63±22.06) mm and (30.90±20.30) mm, Schiff score 2.13±0.67, 1.97±0.66 and 1.42±0.56. After the application of bioactive glass, the values of Tactile, the VAS, and the Schiff score were statistically different from those at baseline or after application of the placebo (P＜0.05). The data measured at baseline and after application of the placebo were of no statistical difference (P＞0.05). Statistical differences between the Schiff scores of the groups were associated with gender, tooth position, primary or secondary tooth preparation. Conclusion: Results of the clinical trial showed that the powders of 45S5 bioactive glass were significantly effective on reducing the hypersensitivity of teeth with vital pulp after the full crown preparation.

Key words: Bioactive glass, Dentin sensitivity, Tooth preparation