Tensile bond strength of four adhesive systems to dentin.

PURPOSE: To assess, in vitro, the tensile bond strength to dentin of the following adhesive systems: Single Bond (3M), One Coat Bond (Coltène), Clearfil Liner Bond 2 V (Kuraray) and Etch & Prime 3.0 (Degussa). MATERIALS AND METHODS: Thirty third molars, extracted according to therapeutic indication, were used. The roots were removed at the cement-enamel junction level and the crowns were sectioned in a mesial-distal direction, obtaining buccal and lingual halves. The dental portions were included in self-cured acrylic resin, abraded on a lathe under water spray and polished to 400 and 600 grit. The adhesive systems were applied on dentin according to manufacturers' instructions and resin-based composite (Z100) cones were bonded. For each adhesive system, 15 specimens were prepared, stored in distilled water at 37 degrees C during 24 hrs and submitted to tensile bond strength tests on a universal testing machine (EMIC DL-2000) at a crosshead speed of 0.5 mm/min. RESULTS: The mean tensile bond strength to dentin (MPa +/- SD) were statistically different (ANOVA, Tukey's tests, P < or = 0.01, shown by asterisks) from each other: (1) Clearfil Liner Bond 2 V* = 24.8 +/- 3.3; (2) One Coat Bond** = 20.4 +/- 2.0; (3) Single Bond** = 18.1 +/- 2.4; (4) Etch & Prime 3.0*** = 5.8 +/- 2.4.

Comparative study of influence on tensile bond strength of a composite to dentin using Er:YAG laser, air abrasion, or air turbine for preparation of cavities.

OBJECTIVES: The purpose of this study was to evaluate, in vitro, the tensile bond strength of the Single Bond (3M) adhesive system placed over dentin surfaces treated with air turbine, Er:YAG laser without contact and in focused or air abrasion. SUMMARY BACKGROUND DATA: The use of dentin adhesives is a well-established clinical routine among the dentists. However, there have been few reports comparing the influence of the Er:YAG laser, air abrasion, and air turbine on the Single Bond tensile bond strength of adhesives systems to dentin fact that could influence which tools dentists select for use in cavity preparations. METHODS: Twenty-three extracted retained human molars were used in this study. The coronal portion was divided in two parts and fixed in acrylic resin; the occlusal surface was abraded to a 2-mm width with a mechanic lathe until the dentin surface was completely exposed. The dental portions were divided into three groups of 15 each and treated with Er:YAG laser, air abrasion, or air turbine. A 3 mm hole in the center of each tooth was marked off using contact paper. Single Bond (3M) adhesive system was applied after acid phosphoric at 35% application for 15 sec over dentin surfaces. A resin composite cone was built into the delimited area to accomplish the tensile bond strength test on the EMIC universal test machine. The specimens were then evaluated by stereoscopy to determine the type of failures into the dentin-adhesive-resin composite surface. RESULTS: The tensile test was performed using the universal testing machine EMIC DL-2000 at a cross-head speed of 0.5 mm/min. The average results were: air turbine (17.52 MPa), Er:YAG laser (16.65 MPa) and air abrasion (15.83 MPa). Statistical treatment by ANOVA and Tukey's test (p < 0.01) showed no significant differences between the groups tested. The tensile bond strength test to the dentin showed no significant difference among the three groups when the Single Bond was used after the 35% phosphoric-acid conditioning. The stereoscopy showed a predominant adhesive failure in all groups. CONCLUSION: These results suggest that Single Bond tensile bond strength is the same as dentin prepared by Er:YAG laser, air abrasion, or air turbine.

Chemical etching solutions for creating micromechanical retention in resin-bonded retainers.

This study introduced three chemical etching solutions capable of producing micromechanical retention in nickel-chromium and nickel-chromium-beryllium alloys used for resin-bonded retainers. The effectiveness of the chemical etching solutions was evaluated with tensile strength tests and photographs at various magnifications with a scanning electron microscope. Chemical etching with the CG-Etch solution produced suitable and uniform microretention whereas the other solutions were not effective on all metal alloys. Significant differences (p < 0.05) relating to tensile bond strengths were noted. The CG-Etch solution gave the highest mean bond strength compared with solutions II, III, and control groups.