Effect of latex glove contamination on bond strength

This study examined the effect of powdered and powder-free latex glove contamination on bond strength.

Sixty caries-free human third molars were mounted in acrylic, sectioned with a diamond saw to expose a flat occlusal dentin surface, and finished with 400- and 600-grit silicon carbide paper. Teeth were assigned to one of 5 groups: 1) no latex glove contamination (control); 2) powdered latex glove contamination before etching; 3) powder-free latex glove contamination before etching; 4) powdered latex glove contamination after dentin bonding agent application but prior to resin composite placement; 5) powder-free latex glove contamination after dentin bonding agent application but prior to resin composite placement. Excite dentin bonding agent was used per manufacturer's instructions. Z-250 resin composite was applied in 2- x 2-mm increments using a split Teflon mold, each light cured for 20 s. Bonded samples were thermocycled 500 cycles between 5 degrees C and 55 degrees C water baths. Specimens were stored in 37 degrees C distilled water. One-week shear bond strength values were determined using a Tinius Olsen testing machine at a crosshead speed of 0.5 mm/min. Results were analyzed with one-way ANOVA (alpha = 0.05).

No significant difference (p = 0.47) in bond strength was found between the experimental groups and the control. Groups 1, 2, 3, and 5 exhibited predominantly mixed failures while the majority of samples in Group 4 showed adhesive failures.

Under the conditions of this study, contamination of dentin by powdered or powder-free latex gloves did not significantly affect bond strength. Future research should be directed toward evaluating the effects of dentin contamination on bond strength of other bonding agents and include ultrastuctural examination in determining what role, if any, powder plays as a contaminant.