An In Vitro Comparison of Dentinal Tubule Occlusion by Sodium Fluoride and Bioactive Glass Varnishes With and Without Erbium:Yttrium-Aluminum-Garnet (Er:YAG) Laser Activation

Background Laser irradiation effectively occludes dentinal tubules, reducing dentine hypersensitivity and improving restorative outcomes. Sodium fluoride varnish is widely used for dentinal sensitivity, while bioactive glass varnish promotes mineral deposition. The Erbium:Yttrium-Aluminum-Garnet (Er:YAG) laser, due to its high absorption by water and hydroxyapatite, may enhance the occlusive efficacy of these desensitizing agents. Objective This study aimed to evaluate the effect of Er:YAG laser activation on the dentinal tubule-occluding efficacy of sodium fluoride and bioactive glass varnishes. Methods Sixteen extracted premolars were sectioned to yield 32 dentinal discs and divided into two main groups: sodium fluoride (Poco) and bioactive glass (Prevest). Each group was further subdivided into varnish application without laser activation and varnish application with Er:YAG laser activation. The mean number of open dentinal tubules was evaluated using scanning electron microscopy (SEM). Data were analyzed using IBM SPSS Statistics for Windows, Version 26 (released 2018; IBM Corp., Armonk, NY, USA). Normality was assessed using the Shapiro-Wilk test, followed by one-way analysis of variance (ANOVA) and Tukey's post hoc test at a 95% confidence level. Results A statistically significant difference was observed among the four groups (p < 0.05), primarily due to the laser-activated bioactive glass varnish, which showed the greatest dentinal tubule occlusion. Laser-activated sodium fluoride varnish and the non-laser groups showed intermediate tubule occlusion, with sodium fluoride without laser having the highest number of open tubules. Conclusions Er:YAG laser activation significantly enhances the tubule-occluding efficacy of both varnishes. Laser-activated bioactive glass varnish demonstrated the highest effectiveness, suggesting a potential utility in reducing dentinal hypersensitivity.