Effect of Carbamide Peroxide Bleaching Gel on Composite Resin Flexural Strength and Microhardness

Gabriel Rodrigues Hatanaka,Carlos Alberto Dos Santos Cruz,Antonio Alves De Almeida-Junior,Filipe De Oliveira Abi-Rached

doi:10.1590/0103-6440201302155

Gabriel Rodrigues Hatanaka, Carlos Alberto Dos Santos Cruz + Show 2 more

Open Access

https://doi.org/10.1590/0103-6440201302155

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Abstract

This study investigated the effect of 16% carbamide peroxide (Whiteness Perfect/FGM) on the Vickers microhardness and flexural strength of the restorative composites Filtek Z100 (hybrid), Filtek Z350 (nanofill), Brilliant (micro-hybrid) and Opallis (micro-hybrid). Disc-shaped (4x2 mm; n=5) and bar-shaped (12x2x1 mm; n=10) specimens of each restorative material were randomly divided into 2 groups: (G1) 16 weeks stored in distilled water; (G2) 16 weeks stored in distilled water, with 16% carbamide peroxide application during 6 h per day for the last 4 weeks. The mechanical properties were evaluated using a Vickers microhardness tester and a mechanical testing machine. Data were analyzed by two-way ANOVA and Tukey's (HSD) post-hoc test (α=0.05). Filtek Z100 presented the highest microhardness value, followed by Filtek Z350 and finally by Brilliant and Opallis (p=0.00). Filtek Z100 and Brilliant exhibited the highest flexural strength value, followed by Filtek Z350 and Opallis (p=0.00). Bleaching treatment decreased significantly microhardness of Brilliant and Opallis (p=0.00). The flexural strength of all studied materials was not affected by the home bleaching (p=0.28).

Highlights

Dental bleaching has been widely used in dentistry as an effective and non-invasive aesthetic dental treatment [1]
Studies have investigated the effects of bleaching agents on several restorative materials used in the posterior region of oral cavity, such as amalgam [7], composite resins [8,9,10,11,12,13], glass ionomer cement [11,13,14] and feldspathic porcelain [11,14]
The specimens of each restorative material were randomly divided into 2 groups: (G1) 16 weeks stored in distilled water, without bleaching agent application; (G2) 16 weeks stored in distilled water, with 16% carbamide peroxide (Whiteness Perfect; FGM Produtos Odontológicos, Joinville, SC, Brazil) application during 6 h per day for the last 4 weeks

Summary

Introduction

Dental bleaching has been widely used in dentistry as an effective and non-invasive aesthetic dental treatment [1]. Studies have investigated the effects of bleaching agents on several restorative materials used in the posterior region of oral cavity, such as amalgam [7], composite resins [8,9,10,11,12,13], glass ionomer cement [11,13,14] and feldspathic porcelain [11,14]. According to these studies, bleaching agents are able to modify the porosity [14], hardness [15], flexural strength [13] and color stability [16] of restorative composites

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