# Role of diode laser (810 nm) and/or fluoride varnish for the treatment of gamma-irradiated hypersensitive human dentin (An in vitro study)

## TL;DR

This study tests how diode laser and fluoride varnish help reduce dentin hypersensitivity in human teeth exposed to gamma radiation.

## Contribution

The study introduces a novel combination of diode laser and fluoride varnish for managing dentin hypersensitivity in gamma-irradiated teeth.

## Key findings

- The combination of diode laser and fluoride varnish was most effective in maintaining dentinal tubule occlusion after acid exposure.
- Fluoride varnish and laser treatment alone showed increased open dentinal tubules after acid challenge.
- Gamma-irradiated dentin had the highest initial open dentinal tubule percentage.

## Abstract

Head and neck cancer is the sixth most frequent cancer worldwide. Dentin hypersensitivity (DH) is a common complication in patients undergoing radiotherapy. Gamma radiation significantly affects dental hard tissues, particularly dentin. Management of DH can be achieved using different agents such as fluoride and laser. This study aimed to evaluate the effectiveness of diode laser (810 nm), fluoride varnish, and their combination in managing DH in gamma-irradiated hypersensitive human dentin. Forty dentin specimens were assigned into four groups, G; gamma-irradiation only, GF; gamma-irradiation then fluoride varnish, GL; gamma-irradiation then laser, GFL; gamma-irradiation then fluoride then laser. Specimens were qualitatively assessed before and after citric acid challenge using environmental scanning electron microscope (ESEM). Image analysis for ESEM photomicrographs was performed to quantitatively evaluate the percentage of open dentinal tubules (DTs). The percentage of open DTs of group G before citric acid challenge showed the highest value that insignificantly increased after acid challenge. The percentage of open DTs of GF and GL groups significantly increased after citric acid challenge. The percentage of open DTs of group GFL insignificantly increased after citric acid challenge. Groups can be arranged according to the percentage of open DTs descendingly before citric acid challenge: G > GL > GFL > GF and after citric acid challenge: G > GF > GL > GFL. The combination of diode laser and fluoride varnish proves most effective in maintaining DTs occlusion following citric acid, offering a promising strategy for managing DH in patients undergoing radiotherapy.