Effect of deproteinization and tubular occlusion on microtensile bond strength and marginal microleakage of resin composite restorations

Abstract

Dentin adhesion procedure presents limitations, especially regarding to lifetime stability of formed hybrid layer. Alternative procedures have been studied in order to improve adhesion to dentin. Objective: The aim of this study was to evaluate in vitro the influence of deproteinization or dentin tubular occlusion, as well as the combination of both techniques, on microtensile bond strength μTBS) and marginal microleakage of composite resin restorations. Material and Methods: Extracted erupted human third molars were randomly divided into 4 groups. Dentin surfaces were treated with one of the following procedures: (A) 35% phosphoric acid gel (PA) + adhesive system (AS); (B) PA + 10% NaOCl + AS; (C) PA + oxalate + AS and (D) PA + oxalate + 10% NaOCl + AS. Bond strength data were analyzed statistically by two-way ANOVA and Tukey's test. The microleakage scores were analyzed using Kruskal-Wallis and Mann-Whitney non-parametric tests. Significance level was set at 0.05 for all analyses. Results: μTBS data presented statistically lower values for groups D and B, ranking data as A>C>B>D. The use of oxalic acid resulted in microleakage reduction along the tooth/restoration interface, being significant when used alone. On the other hand, the use of 10% NaOCl alone or in combination with oxalic acid, resulted in increased microleakage. Conclusions: Dentin deproteinization with 10% NaOCl or in combination with oxalate significantly compromised both the adhesive bond strength and the microleakage at interface. Tubular occlusion prior to adhesive system application seems to be a useful technique to reduce marginal microleakage.

Etidronate from Medicine to Endodontics: effects of different irrigation regimes on root dentin roughness

“…The use of NaOCl solutions has been suggested as a strategy to remove this exposed collagen matrix in a process called deproteination 4,14 , which restores to the surface characteristics of untreated dentin 7 .…”

Influence of Sodium Hypochlorite on Er:YAG Laser-Irradiated Dentin and its Effect on the Quality of Adaptation of the Composite Restoration Margins

“…On the contrary, other studies have shown that NaOCl treatment at different concentrations and reaction times can achieve complete removal of collagen fibers. [35][36][37] NaOCl, at a concentration of 5%, was used in some studies 38,39 in which the authors obtained elimination of the organic substance, without alteration of mechanical properties; in contrast, high concentrations such as 10% 40,41 were used in studies, which reported an increase in microleakage. For all these reasons, a concentration of 5% NaOCl was chosen, the concentration mainly used in endodontic treatment.…”

The Effect of Er:YAG Laser Irradiation and Different Concentrations of Sodium Hypochlorite on Shear Bond Strength of Composite to Primary Teeth’s Dentin

“…30 Therefore, some studies has recommended to use NaOCl in concentrations varying from 2.5% to 13% after dentin etching, to remove the remained collagenous layer and to [16][17][18] Using sodium hypochlorite at a concentration of 5% removes the organic materials without any change in the mechanical properties of the dentin, compared to higher concentration (10%(, which increases micro-leakage. 29,32 For all these reasons, 2.5% and 5.25% concentrations of sodium hypochlorite were used in this study. It seems as well that the efficiency of treatment with NaOCl in improving bond strength depends on the type of solvent solution contained in the adhesive system.…”