In vitro comparative SEM analysis of nano-hydroxyapatite toothpaste and diode laser: evaluation of efficacy of dentinal tubular occlusion

Introduction
Dentin hypersensitivity (DH) is a very common problem that faces many patients and maintaining treatments with a long term effectiveness remains a challenge. Based on hydrodynamic theory, the main approach of overcoming DH are tubular occlusion.

Objectives
The aim of this study was to discover the efficacy of diode laser alone and in combination with a desensitizing toothpaste containing nano-hydroxyapatite (nHap) to evaluate dentinal tubule occlusion after acid challenge under scanning electron microscope (SEM).

Material and methods
Forty dentin discs were divided into 4 groups: group 1, control; group 2, dentin disc treated with nHap toothpaste for one week; group 3, discs treated with diode laser in non-contact mode for 60 seconds; group 4, discs treated with nHap toothpaste for one week, followed by laser application. SEM analysis was performed after acid challenge to the discs.

Results
Tubular occlusion was evident in all groups after acid challenge; however, group 4 showed the most occluded tubules, which was the most resistant to acid challenge.

Conclusions
Combination of diode laser and toothpaste containing nHap has a greater effect on occluding dentinal tubules rather than each treatment alone.