Micromorphology and microhardness of enamel after treatment with home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide.

Robson Tetsuo Sasaki,Roberta Tarkany Basting,Alex José Arcanjo,Flávia Martão Flório

doi:10.1590/s1678-77572009000600014

Robson Tetsuo Sasaki, Roberta Tarkany Basting + Show 2 more

Open Access

https://doi.org/10.1590/s1678-77572009000600014

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Abstract

Objective:The purpose of this study was to assess the effect of home-use bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide on enamel microhardness and surface micromorphology.Material and Methods:Enamel slabs (n=10) received the bleaching agents for 1 h/day and remained in artificial saliva solution for 23 h/day, during a total period of 21 days. Control group was composed of enamel slabs that were not subjected to treatment with the agents and were maintained in artificial saliva solution. Microhardness tests were performed before treatment application, 21 days of treatment and 14 days after the end of treatment. Scanning electron microscopy analyses were performed after 14 days after the end of bleaching treatment by 3 calibrated observers who attributed scores.Results:The Tukey's test (α=0.05) showed no significant differences in microhardness values among bleaching agents, at 21 days of treatment and a significant increase in microhardness for different agents after 14 days from the end of treatment. Fisher's exact test showed differences in micromorphology of enamel between control and experimental groups (p=0.0342).Conclusions:Bleaching agents containing 10% carbamide peroxide and 7.5% hydrogen peroxide may change surface micromorphology of enamel, although no changes in microhardness were observed.

Highlights

The search for a more esthetic smile has grown exponentially in the last few decades
Studies have evaluated the effect of carbamide peroxide used in the home bleaching technique on the superficial micromorphology of dental structure in regimens lasting longer than an 1 h
No study has reported how enamel microhardness and micromorphology are presented at the end of a bleaching regimen of 1 h/day application during 21 days, as recommended by manufacturers of bleaching products with different compositions: carbamide or hydrogen peroxide agents

Summary

Introduction

The search for a more esthetic smile has grown exponentially in the last few decades. In order to meet this demand, many studies have been developed about dental bleaching and its effects on dental structure. Modifications, improvements and variations of the technique, such as different concentrations of carbamide peroxide agents (10 to 22%) with carbopol and hydrogen peroxide agents were developed. Studies have evaluated the effect of carbamide peroxide used in the home bleaching technique (with trays) on the superficial micromorphology of dental structure in regimens lasting longer than an 1 h. No study has reported how enamel microhardness and micromorphology are presented at the end of a bleaching regimen of 1 h/day application during 21 days, as recommended by manufacturers of bleaching products with different compositions: carbamide or hydrogen peroxide agents

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