• Restorative Dentistry and Endodontics
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• v.40 no.1
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• pp.68-74
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• 2015

Objectives: This study examined the effects of additional acid etching on the dentin bond strength of one-step self-etch adhesives with different compositions and pH. The effect of ethanol wetting on etched dentin bond strength of self-etch adhesives was also evaluated. Materials and Methods: Forty-two human permanent molars were classified into 21 groups according to the adhesive types (Clearfil SE Bond [SE, control]; G-aenial Bond [GB]; Xeno V [XV]; Beauti Bond [BB]; Adper Easy Bond [AE]; Single Bond Universal [SU]; All Bond Universal [AU]), and the dentin conditioning methods. Composite resins were placed on the dentin surfaces, and the teeth were sectioned. The microtensile bond strength was measured, and the failure mode of the fractured specimens was examined. The data were analyzed statistically using two-way ANOVA and Duncan's post hoc test. Results: In GB, XV and SE ($pH{\leq}2$), the bond strength was decreased significantly when the dentin was etched (p < 0.05). In BB, AE and SU (pH 2.4 - 2.7), additional etching did not affect the bond strength (p > 0.05). In AU (pH = 3.2), additional etching increased the bond strength significantly (p < 0.05). When adhesives were applied to the acid etched dentin with ethanol-wet bonding, the bond strength was significantly higher than that of the no ethanol-wet bonding groups, and the incidence of cohesive failure was increased. Conclusions: The effect of additional acid etching on the dentin bond strength was influenced by the pH of one-step self-etch adhesives. Ethanol wetting on etched dentin could create a stronger bonding performance of one-step self-etch adhesives for acid etched dentin.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.1
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• pp.37-44
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• 2013

Sodium hypochlorite and ethylene diamine tetra acetic acid are substances usually used during endodontic treatment. Several studies found that the bonding was negated with certain irrigants and some of the used irrigants have demineralizing and chealating effects, so it was advocated to omit the etching step in etch and rinse adhesive systems. The purpose of this in vitro study was to evaluate the influence of NaOCl & EDTA on the bonding strength of ethanol wet bonding. Thirty human molars were selected and mesiodistally sectioned into halves, thus providing sixty specimens. The specimens were randomly assigned to 4 groups(n=15) according to the irrigant regimen used : (1) irrigated with distilled water for 10min (control); (2) irrigated with 5.25% NaOCl(10min), flushed with 5.25% NaOCl(1min) (3) irrigated with 5.25% NaOCl, flushed with 17% EDTA (4) irrigated with 5.25% NaOCl, flushed with 17% EDTA. Each group was acid-etched with 37% phosphoric acid(except group 4) and had their dentin surfaces dehydrated with ethanol solutions : 50%, 70%, 80%, 95%, 3x100%, 30s for each application. After dehydration, a primer( 50% all bond 3 resin + 50% ethanol) was used, followed by the adhesive(ALL-BOND 3 RESIN) application. Resin composite build-ups were then prepared using an incremental technique. Specimens were sectioned into beams and submitted to a tensile load using a Micro Tensile Tester(Bisco Inc.). The data were statistically analyzed using one-way ANOVA and Tukey HSD at p<0.5 level. There was no significant difference on G1(control) and G2(irrigated with NaOCl only ). (p>0.05). G3(flushed with EDTA) showed significantly high tensile bonding strength compared to the G2 (p<0.05). G4( treated with EDTA but no acid-etching) was significantly lower value than G3. (p<0.05) Although there was no significant difference, 5.25% NaOCl seemed to have an adverse effect on the bonding strength of ethanol wet bonding. The flushing with EDTA after NaOCl irrigation prevents the decrease of bonding strength. The use of 17% EDTA as a final flush can enhance the bonding strength but EDTA flushing can't substitute for a acid-etching.

• Restorative Dentistry and Endodontics
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• v.37 no.1
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• pp.2-8
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• 2012

The limited durability of resin-dentin bonds severely compromises the longevity of composite resin restorations. Resin-dentin bond degradation might occur via degradation of water-rich and resin sparse collagen matrices by host-derived matrix metalloproteinases (MMPs). This review article provides overview of current knowledge of the role of MMPs in dentin matrix degradation and four experimental strategies for extending the longevity of resin-dentin bonds. They include: (1) the use of broadspectrum inhibitors of MMPs, (2) the use of cross-linking agents for silencing the activities of MMPs, (3) ethanol wet-bonding with hydrophobic resin, (4) biomimetic remineralization of water-filled collagen matrix. A combination of these strategies will be able to overcome the limitations in resin-dentin adhesion.

• Restorative Dentistry and Endodontics
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• v.34 no.1
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• pp.42-50
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• 2009

Deterioration of long-term dentin adhesion durability is thought to occur by hydrolytic degradation within hydrophilic domains of the adhesive and hybrid layers. This study investigated the hypothesis that priming the collagen network with an organic solvent displace water without collapse and thereby obtain good bond strength with an adhesive made of hydrophobic monomers and organic solvents. Three experimental adhesives were prepared by dissolving two hydrophobic monomers, bisphenol-A-glycidylmethacrylate (Bis-GMA) and triethyleneglycol dimethacrylate (TEGDMA), into acetone, ethanol or methanol. After an etching and rinsing procedure, the adhesives were applied onto either wet dentin surfaces (wet bonding) or dentin surfaces primed with the same solvent (solvent-primed bonding). Microtensile bond strength (MTBS) was measured at 48 hrs, 1 month and after 10,000 times of thermocycles. The bonded interfaces were evaluated using a scanning electron microscope (SEM). Regardless of bonding protocols, well-developed hybrid layers were observed at the bonded interface in most specimens. The highest mean MTBS was observed in the adhesive containing ethanol at 48 hrs. With solvent-primed bonding, increased MTBS tendencies were seen with thermo cycling in the adhesives containing ethanol or methanol. However, in the case of wet bonding, no increase in MTBS was observed with aging.