Influence of aging methods on push-out bond strength of adhesive systems to dentin cavities

Letícia Virgínia De Freitas Chaves,Tuany Arantxa De Medeiros,Anderson Catelan,Boniek Castillo Dutra Borges,Maria Do Carmo Aguiar Jordão Mainardi,Flávio Henrique Baggio Aguiar

doi:10.1186/s40563-016-0079-z

Abstract

This study evaluated the effect of aging methods on the bond strength of etch-and-rinse adhesive systems to dentin cavities. Eighty bovine incisors were used to prepare dentin cavities, which were bonded with different adhesive systems [Adper Scotchbond Multipurpose (SBMP), and Adper Single Bond 2 (SB)], and restored with composite resin. The specimens were stored in water for 24 h, and subjected to each aging method (n = 10): control group (not exposed to additional aging), thermal cycling (TC) (10,000 cycles; at temperatures of 5, 37, and 55 °C), mechanical loading (ML) (100,000 cycles; Hz; 60 N load), and TC + ML. The push-out bond strength test was performed using a universal testing machine. Failure modes were evaluated by scanning electron microscopy. Data were analyzed by two-way ANOVA and Tukey’s test (α = 0.05). For SBMP, only TC + ML decreased the bond strength compared to control group. For SB, all aging methods decreased similarly the bond strength compared to control group. A high number of adhesive failures were observed. Therefore, SB was sensitive to all aging methods, whilst only TC + ML was able to decrease the bond strength for SBMP.

Highlights

The main challenge for dental adhesives is providing an effective bond to enamel and dentin
For Scotchbond Multipurpose (SBMP), no aging provided statistically similar bond strength mean to thermal cycling (TC) and mechanical loading (ML), which were statistically higher than the mean provided by TC + ML
SBMP showed higher bond strength values compared to Single Bond 2 (SB) in specimens aged by TC and ML

Summary

Introduction

The main challenge for dental adhesives is providing an effective bond to enamel and dentin. Microtensile bond strength and microshear bond strength tests are frequently used to investigate immediate and long-term dentin bond strength (after ageing methods) [3, 4] These methods are routinely used in flat dentin surfaces in which C-factor is low, and the development of shrinkage stress is not directed toward the bonding interface [5], different from what it occurs in posterior tooth restoration in the oral environment. For this reason, push-out bond strength test has been used to evaluate adhesive performance in tooth cavities, where the composite shrinks into a high C-factor

Methods

Results

Discussion

Conclusion