Effect of Non-Vital Bleaching on the Durability of Resin⁻Dentin Bond with an Ethanol-Based Etch-And-Rinse Adhesive.

Alireza Boruziniat,Majid Akbari,Mahshid Gifani,Zafer Chehreli,Atefeh Atoufi

doi:10.3390/biomimetics3040035

Alireza Boruziniat, Majid Akbari + Show 3 more

Open Access

https://doi.org/10.3390/biomimetics3040035

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Abstract

To evaluate the bleaching procedure and application of sodium ascorbate on dentin bond durability, the enamel surface of intact human third molars (n = 18) were removed, and the teeth were randomly divided into two groups for immediate and six-month bond strength evaluation. The specimens were further assigned into three subgroups according to treatment procedure, as follows: subgroup A, no bleaching (positive control) was performed prior to the etch-and-rinse bonding with single bond and subsequent build-up with Z250 composite; subgroup B, the samples were bleached with 20% carbamide peroxide 6 h/day for five consecutive days prior to bonding; and subgroup C, bleaching was performed as in subgroup B, after which 10% sodium ascorbate was applied on dentin surface for 10 min before the bonding procedures. A microtensile bond strength test was performed and the failure modes were evaluated under a stereomicroscope. The data were analyzed using two-way analysis of variance (ANOVA) and Tukey’s post-hoc tests with a level of significance of 0.05. Bleaching significantly decreased the immediate and six-month bond strength. The application of sodium ascorbate had no significant effect on the immediate and six-month bond strength of bleached specimens. We conclude that the bleaching procedure may decrease the durability of the resin–dentin bond of the tested etch-and-rinse adhesive.

Highlights

Bleaching is an established method to manage tooth discoloration via the application of oxidizing agents
Toledano et al [20] and Sato et al [21] demonstrated that bleaching agents may activate matrix metalloproteinases (MMPs), which, in turn, can destroy exposed collagen fibrils and degrade the Biomimetics 2018, 3, 35; doi:10.3390/biomimetics3040035
This finding may be attributed to the activation of MMPs by the release of free radicals and is consistent with previous work by Toledano et al [20] and Sato et al [21], who showed that bleaching agents can activate MMPs

Summary

Introduction

Bleaching is an established method to manage tooth discoloration via the application of oxidizing agents. Interference with resin infiltration and polymerization, as well as an alteration of the tooth structure are the main reasons for up to a 67% reduction in bond strength [4,6,7]. Different methods have been suggested to improve bond strength, which vary from postponing adhesive restorative procedures for up to three weeks, to the use of antioxidant agents or organic solutions such alcohol or acetone [10,11,12,13,14,15,16,17,18,19].

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