Effect of internal bleaching agents on the bond strength of glass fiber posts to root dentine

Josemar Martins Ferreira,Sara Rodrigues Renovato,Daniel De Almeida Decurcio,Carlos José Soares,Carlos Estrela,Fernanda Ribeiro Santana

doi:10.15448/1980-6523.2016.3.20490

Josemar Martins Ferreira, Sara Rodrigues Renovato + Show 4 more

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https://doi.org/10.15448/1980-6523.2016.3.20490

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Abstract

Objective: This study evaluated the effect of internal bleaching agents on the bond strength of glass fiber posts to root dentine.Methods: Seventy bovine teeth were divided into 7 experimental groups (n=10) according to the bleaching agent used: SpH – sodium perborate + 20% hydrogen peroxide; SpW – sodium perborate + distilled water; Cp37 – 37% carbamide peroxide; Cp16 – 16% carbamide peroxide; Cp10 – 10% carbamide peroxide; H – 35% hydrogen peroxide; C – no bleaching agent (control). After bleaching, posts were cemented with a self-adhesive resin cement (RelyX U100) and the roots were crosssectioned to obtain two discs from each third. The posts underwent micropush-out testing, and bond strength values (MPa) were analyzed using ANOVA in a split-plot arrangement and the Tukey test (p<0.05). Failure mode was evaluated under confocal microscopy.Results: There were no significant differences between the control and bleaching agent groups. Bond strength was greater in the cervical third of the 16% carbamide peroxide (Cp16) group than in the sodium perborate + 20% hydrogen peroxide (SpH) group. The cervical third had a higher bond strength than the apical third in the 10% carbamide peroxide (Cp10), 16% carbamide peroxide (Cp16) and sodium perborate + distilled water (SpW) groups, and no significant differences in the other groups. Adhesive cement-dentine failure was prevalent in all groups.Conclusion: The use of internal bleaching agents did not decrease the bond strength of glass fiber posts to root dentin.

Highlights

An attractive smile may be compromised by tooth color, and discoloration of a tooth is an aesthetic change that usually requires treatment [1]
Falhas adesivas de cimento-dentina foi prevalente em todos os grupos
Of 300 freshly extracted teeth, 70 were selected because of their similarity in external and internal anatomy. They were divided into seven groups (n=10), according to bleaching agent: SpH – sodium perborate + 20% hydrogen peroxide (Whiteness Perborato, FGM, Joinville, Brazil); SpW – sodium perborate + distilled water (Whiteness Perborato, FGM, Joinville, Brazil); Cp37 – 37% carbamide peroxide (Whiteness Super-Endo, FGM, Joinville, Brazil); Cp16 – 16% carbamide peroxide (Whiteness Perfect 16%, FGM, Joinville, Brazil); Cp10 – 10% carbamide peroxide (Whiteness Perfect 10%, FGM, Joinville Brazil); H – 35% hydrogen peroxide (Whiteness HPMaxx, FGM, Joinville, Brazil); C – no bleaching agent

Summary

Introduction

An attractive smile may be compromised by tooth color, and discoloration of a tooth is an aesthetic change that usually requires treatment [1]. Common causes of discoloration of pulpless teeth are injury or breakdown of pulp tissue, intrinsic changes due to intrapulpal hemorrhage and chromophores within the root canal [2,3]. Few studies in the literature evaluated bonding to root dentine after internal bleaching of endodontically treated teeth. These teeth usually have insufficient coronal structure to retain restorative material, and a post has to be used for coronal reconstruction. Glass fiber posts and resin cement are widely accepted today as alternatives to cast posts [15,16,17,18,19]

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