Gluteraldehyde combined with Phosphoric Acid as Crosslinking Agent

Objective: To evaluate if the addition of 1, 3, or 5% Glutaraldehyde to the phosphoric acid improves the bond strength of resin to dentin by stiffening the collagen scaffold during etching, when using a three-step etch-and-rinse adhesive system. Method: 70 extracted 3^rd molars were obtained and stored in 0.2% chloramines T at 4^oC until used.  They were embedded in acrylic resin.  A flat dentinal tooth surface was obtained by grinding the tooth surface with a 600-grit silicon carbide paper to create fresh smear layer.  The samples were randomly divided into five groups (n=14), (1) 1% Glutaraldyhyde (GA) and 37% H₃PO₄ and dried after etch, (2) 3% GA and 37% H₃PO₄ and dried, (3) 5% GA and 37% H₃PO₄ and dried, (4) 37% H₃PO₄ and dried, and (5) 37% phosphoric acid and left slightly moist.  Agents were compounded by the pharmacy at the College of Dentistry.  Optibond FL, primer and adhesive were placed according to manufacturer's instructions and Filtek Supreme Plus shade A2 was used to make a 2.38 mm diameter composite button on each sample.  Specimens were loaded in shear using a universal testing machine at a cross head speed of 1 mm/min until failure. Results:  One-way ANOVA with appropriate post-hoc Tukey's test was used to test for differences with a significance value of 0.05.  The p-value of 0.0810 suggested that there was no significant difference among the five groups.  The averages and standard deviation are shown below. <> Mean Shear Bond Strength by the Experimental Groups

Conclusion: The addition of GA did not affect the bond strength of resin composite to dentin.