# Effect of nanohydroxyapatite paste after different pretreatment techniques on remineralization and color change of white spot lesions in children: a randomized control study

## TL;DR

This study compares how well nanohydroxyapatite paste, with or without pretreatment, can remineralize and improve the color of early tooth decay in children.

## Contribution

The study evaluates the effectiveness of nanohydroxyapatite with different pretreatments for remineralizing white spot lesions in children.

## Key findings

- NHA paste significantly improved remineralization and color change compared to no treatment.
- Pretreatment with microabrasion or sodium hypochlorite enhanced NHA's effectiveness.
- Results were measured using Diagnodent and Vita easy shade devices over six weeks.

## Abstract

White spot lesions (WSLs) are initial caries caused by early demineralization. Nanohydroxyapatite (NHA) paste is one of the most recent non-fluoridated remineralizing agents; however, few clinical studies have reported its remineralizing effect on such lesions. The aim of this study was to compare and evaluate the remineralization and color change of WSL after NHA alone was used versus NHA pretreatment with either microabrasion or sodium hypochlorite (NaOCl) and no treatment as a negative control.

Twenty children aged 10 to 14 years with 40 teeth affected with WSL; were randomly assigned to 4 groups (10 teeth in each group); group I: pretreatment with microabrasion followed by NHA paste, group II: pretreatment with 5.25% NaOCl, followed by NHA paste, group III: NHA paste alone, and group IV: negative control with no treatment applied. The remineralization ability was assessed via diagnodent device and color changes were assessed via a Vita easy shade device before and after treatment; and one, two and six weeks after treatment.

For the change in Diagnodent readings, there was a significant difference between groups (I, II, III) at different intervals, which as significantly greater than that of group IV at a p value < 0.001. However, for Group IV, the change was not statistically significant (p = 0.332). The color changes measured after 2 and 6 weeks were significantly greater in groups (I), (II) and (III) than group IV (p < 0.001).

NHA could be a good non fluoridated option to remineralize and improve the color of WSL at different treatment intervals. Pretreatment with microabrasion and NaOCl enhances its remineralization and color improvement properties.

This study was retrospectively registered on ClinicalTrials.gov at 6/2/2025, with ID: NCT06834464.

The online version contains supplementary material available at 10.1186/s12903-025-07365-5.