Influence of Acid Etching and Universal Adhesives on the Bond Strength to Dentin

Abstract

The purpose of this study was to evaluate the influence of the application mode of three universal adhesive systems on interfacial physical properties of indirect composite restorations adhesively cemented to dentin cavities. Seventy-eight bovine lower incisors were selected and a slice of dentin (thickness: 2 mm) between the buccal surface and pulp chamber was obtained for each tooth. Conical cavities were made on this surface. The internal walls of the cavities were then coated with a hydrophilic gel, filled with composite resin and photopolymerized. The dentin/cone sets were divided into 6 groups (n=10) according to type of universal adhesive (TETRI: Tetric N Bond, FUT: Futura Bond U, SBU: Single Bond Universal) and acid etching on dentin (A: with acid etching; WA: without acid etching). The acid etching and the adhesive systems were applied to the surface of the dentin. All composite resin cones were sandblasted (Al2O3, 20 s) and silanized. After surface treatment, the cones were cemented (RelyX Ultimate) into the dentin cavity and photopolymerized. After thermocycling (10,000 cycles), samples were submitted to marginal adaptation analysis (using caries detector dye), push-out test (0.5 mm/min), and failure mode analysis. Additional samples were prepared for nanoleakage analysis (SEM). The data (MPa) were analyzed by two-way ANOVA and Tukey’s post-test (5%). The groups in which the dentin was acid etched showed significantly lower bond strength values in the push-out test (p<0.01). Dentin acid etching significantly reduced the bond strength between universal adhesive systems and dentin in indirect restorative procedures.

Adhesive dentistry: Current concepts and clinical considerations

“…One detail that is often overlooked is the use of aggressive phosphoric acid gels with universal adhesives, in spite of not being recommended by the manufacturer of the respective universal adhesive. 86,87 For example, the etchant included with both SBU and SBU Plus decalcifies intertubular dentin to a depth of 1.6 μm, 85 while a more aggressive commercial gel may decalcify dentin to a depth of 4.0-5.0 μm. Thus, a confounding variable is introduced in the study design when a more aggressive etchant is used.…”

Analysis of Pulp Tissue Viability and Cytotoxicity of Pulp Capping Agents

“…Generally, dentin bonding hybridization and adhesive diffusion into dentin tubules may protect the dentin from bacterial leakage, reducing recurrent pulpal inflammation [ 11 , 14 ]. A self-assembled nanolayering of two 10-MDP molecules bonded by a stable MDP-Ca salt formation creates an adhesive interface that is more resistant to biodegradation [ 39 ]. The interaction of a polyalkenoic acid copolymer with the calcium in hydroxyapatite is another chemical process [ 14 ].…”

Effects of the light tip position on the degree of conversion and dentin bond strength of a universal adhesive

“…Mild adhesives with pH between 2 and 3 showed greater degradation resistance irrespective of the application protocol than ultra-mild and intermediately strong which were associated with significantly reduced bond strength after aging [1]. Dentin etching has shown a detrimental effect on adhesive bond strength of several universal adhesives [4,5]. Collagen degradation and resin hydrolysis were associated with biodegradation of universal adhesives and the resulting decrease in bond strength to dentin [4].…”