One-step Adhesive Systems Research Articles

Bonding of a one-step adhesive system to carious dentin with active application mode

Bonding of a one-step adhesive system to carious dentin with active application mode

Effect of sodium hypochlorite on the bond strength of an adhesive system to superficial and deep dentin

The objective of this study was to evaluate the bond strength to superficial (SU) and deep (D) dentin, accessed via apical (DA) or occlusal (DO), using One-Step adhesive system applied according to the manufacturer's instructions (C) or following deproteinization with 10% sodium hypochlorite (H) for 60s, after acid etching. Three sound extracted human molars were prepared for each experimental condition. Restorations were performed using Z100 in 2mm increments, each one being light-cured for 40s. Teeth were longitudinally sectioned to obtain stick-shaped specimens with a cross-sectional area of 0.8mm², which were submitted to bond strength test (0.6mm/min). Results obtained after statistical analysis using a two-way ANOVA (substrate vs. surface treatment) and Tukey's test were: SU (35.4 ± 12.3), DO (26.5 ± 8.5), DA (26.1 ± 10.2) following conventional surface treatment, and SU (28.82 ± 12.7), DO (24.3 ± 8.3) and DA (23.5 ± 8.5), after surface treatment using sodium hypochlorite. The interaction of the factors was not significant (p>0.05). However, the main factors were significant (p<0.05). Mean bond strength values in superficial dentin were statistically superior to deep dentin (p<0.05), although no statistically significant difference was observed between the two via of access to deep dentin (SU>DO=DA). The conventional surface treatment resulted in higher bond strength values than the sodium hypochlorite treatment (p<0.05). It was concluded: 1) bond strength values were higher in superficial dentin, 2) no difference was found between the two deep substrate preparations, and 3) the application of sodium hypochlorite following dentin acid etching may reduce bond strengths.

Bond strength of composite to dentin using conventional, one-step, and self-etching adhesive systems

Objectives: This in vitro study compared the dentin bonding performance of eight adhesive systems using a microtensile bond strength test. Methods: Thirty bovine teeth were ground to 600-grit to obtain flat root-dentin surfaces. Two conventional adhesive systems (Scotchbond Multipurpose Plus, OptiBond FL), four one-step adhesive systems (Scotchbond 1, Asba S.A.C., Prime and Bond NT, Excite) and two self-etching adhesive materials (Clearfil Liner Bond 2 V and Prompt L-Pop) were evaluated. Each bonding system was applied according to manufacturer's instructions and followed by composite (Z100) application. Immediately after bonding, the teeth were prepared for microtensile testing. Bond strength to dentin was measured using a Vitrodyne V-1000 universal tester. There were 14 replicates for each material. Fractured specimens were further observed by SEM. Results: Scotchbond Multipurpose Plus exhibited significantly ( p<0.05) higher bond strength values (30.3±9.4 MPa) than all other materials. The bond strengths of the other materials were (from highest to lowest): Opitbond FL (22.4±4.3 MPa); Scotchbond 1(18.9±3.2); Clearfil Liner Bond 2 V (18.9±3.0); Prime and Bond NT (18.3±6.9); Asba S.A.C. (14.4±2.9); Excite (13.8±3.7); and Prompt L-Pop (9.1±3.3). Statistical comparisons frequently overlapped, but Optibond was significantly ( p<0.05) greater than Asba, Excite, and Prompt L-Pop; whereas, Scotchbond 1 was only significantly ( p<0.05) greater than Prompt L-Pop. Asba, Excite and Prompt L-Pop were not significantly different. The fracture modes were mostly adhesive. Conclusions: The conventional adhesive systems produced higher bond strengths to root dentin than most one-step adhesives and one self-etching adhesive; with the exception of one material in each respective system.

Environmental Effects on RFL Adhesion

Abstract Adhesion deterioration of RFL-dipped tire cord resulting from environmental factors such as ozone, nitrogen dioxide, humidity, ultraviolet light, and heat was investigated to quantify the amount of adhesion loss and to establish the mode of adhesion failure. It was found that ozone, humidity, and ultraviolet light cause substantial adhesion deterioration, especially during the initial hours of exposure. Synergistic effects of ozone/humidity were noted. Less pronounced was the detrimental effect of heat. Adhesion loss because of nitrogen dioxide or synergistic effects of nitrogen dioxide/humidity was not seen. Adhesion loss occurred most rapidly during the first six hours of ozone/humidity exposure, regardless of fiber or adhesive system used. Adhesive treated cords of nylon, polyester, and “Kevlar” aramid showed loss in adhesion; however, no correlation between type of fiber and extent of adhesion deterioration was found. The extent of adhesion deterioration was primarily dependent upon the specific adhesive dip used. Sensitivity of the RFL adhesives to ozone/humidity varied with one- and two-step adhesive systems; with polyester, one-step adhesive systems tested were generally less sensitive to environmental conditions than two-step adhesive systems. The latter, however, had better initial adhesion. Adhesion loss because of ultraviolet light exposure was severe for all RFL adhesives, regardless of fiber. Emission of ultraviolet light from fluorescent lighting was shown to be sufficiently intense to affect adhesion. The physical properties of RFL-dip films were unaffected by ozone or ultraviolet exposure, ruling out cohesive failure of the RFL adhesive as a cause of adhesion breakdown. Adhesion failure for samples tested after environmental exposure occurred at the RFL adhesive-rubber stock interface, indicating the adhesion deterioration to be a RFL surface phenomenon.