# Effect of the β-tricalcium phosphate particle on dental enamel associated with 10% carbamide peroxide bleaching

## TL;DR

This study examines how tricalcium phosphate in toothpaste affects dental enamel during bleaching with carbamide peroxide.

## Contribution

The study evaluates the impact of β-tricalcium phosphate in toothpaste on enamel during bleaching, finding no interference with bleaching efficacy.

## Key findings

- Bleached groups showed significant color changes compared to the control group.
- Toothpastes with β-tricalcium phosphate did not affect bleaching efficacy or enamel microhardness.
- SEM images showed slight mineral deposition but no significant microhardness changes.

## Abstract

Since bleaching gels can cause adverse effects on tooth enamel, it is important to evaluate new remineralizing agents on the market and their effects.

Seventy-five bovine enamel/dentin blocks (4x4x3mm) were randomly divided into six groups (n=10): Negative Control (NC) with no bleaching treatment or brushing; 10 CP (Carbamide Peroxide) (no brushing - Whiteness Perfect FGM); CT12 + 10 CP (Colgate Total® 12); ES + 10 CP (Elmex® Sensitive); BPC + 10 CP (Bianco® ProClinical); CMP + 10 CP (Colgate® Máxima Proteção Anticáries). The color was evaluated by reflectance spectrophotometry (∆E*ab, ∆E00, and ∆WID) at times T1 (baseline), T2 (24 hours after brushing), and T3 (24 hours after bleaching). Knoop microhardness (KHN) analysis were performed at T3. The enamel surface was qualitatively analyzed by Scanning Electron Microscopy (SEM). The data were analyzed using generalized linear models through descriptive and exploratory analyses, and a significance level of 5% was considered.

Significant differences were observed when the bleached groups were compared to the NC group for ∆E*ab, ∆E00, and ∆WID at time T3 (p= <0.0001). However, the bleached groups presented no significant differences regarding studied times (p> 0.05). KHN did not differ significantly among the six groups (p=0.7585).

Toothpastes with tricalcium phosphate (β-TCP) do not intervene with the efficacy of bleaching treatment with 10% carbamide peroxide. Although a slight mineral deposition on enamel surface can be observed on SEM images, KHN was not significantly altered, and the polishing of the samples were maintained.

Key words:Dental Bleaching, Carbamide Peroxide, Hydrogen Peroxide, Dental Enamel, Tricalcium Phosphate.