Effect of theobromine based dental varnish on the enamel surface microhardness- an in vitro study

Abstract

Introduction: Theobromine in recent years has been used as a remineralization agent. It demonstrates increased enamel hydroxyapatite crystal size that strengthens the enamel thus making it resistant to acid attack. Hence in the present study theobromine-based dental varnish was developed and its effect on enamel surface microhardness was assessed. Methods: In this in-vitro study, 45 freshly extracted healthy human first premolar teeth were randomly allocated into three groups of 15. Group 1 was Placebo varnish, Group 2 was Standard 5% Sodium fluoride varnish which was commercially available, and Group 3 was Novel theobromine nanoparticles containing dental Varnish. The enamel blocks were prepared from the randomly selected teeth. Baseline surface microhardness of the prepared enamel blocks were measured at three different points on the polished surface using both Vickers hardness tester and nano-indentation hardness tester. The prepared enamel blocks were immersed in a demineralizing solution for 7 days. At the end of the 7th day, the enamel blocks were removed and cleaned thoroughly. Again, the enamel blocks microhardness was recorded. After demineralization, all the enamel blocks were treated with three different varnishes for 28 days. After the 28th day, the readings were recorded using both Vickers hardness tester and nano-indentation hardness tester again. The results were analyzed by one-way analysis of variance (ANOVA), repeated measures ANOVA, and Bonferroni’s post hoc analysis. Results: The mean enamel surface microhardness between the three groups at baseline (P>0.001) and after demineralization (P>0.001) were not statistically significant whereas after application of dental varnishes the mean enamel surface microhardness values showed significant differences between the groups (P<0.001). Group 3 showed significantly more enamel surface microhardness values after its application on demineralized enamel surface as compared to Group 1 and Group 2 respectively. Conclusions: Theobromine nanoparticles containing dental varnish can significantly increase the enamel surface microhardness after its application on the demineralized early white spot lesion. Keywords: Theobromine, Remineralization, Nanoparticles, Surface microhardness