Comparative Study of the Shear Bond Strength of two Resin Cements Bonded to Enamel and Dentine

Abstract

Background and aim: Fracture resistance depends on adequate bonding to tooth structure. The type of resin luting agents used are believed to produce variability in adhesive properties.

The purpose of this in vitro study was to evaluate the shear bond strength of 2 resin cements bonded to enamel and dentin.

Material and method.

Forty molars were embedded in acrylic resin and ground horizontally with water-cooled silicone carbide paper (600 grit) to expose dentin at the enamel\dentin junction (for dentin groups) and was limited to enamel (in enamel groups). Ten composite cylindrical specimens with a 4-mm diameter and 4-mm height were prepared for each of the following resin cements: Nexus 2 and Rely x . The specimens were bonded to enamel and dentin with these resin cements according to the manufactures' guidelines. After one day of storage in distilled water at 37ºc, specimens were subjected to shear forces in a universal testing machine at a crosshead speed of 0.5 mm\min until fracture. Bond strength data were analyzed with paired t-test. Means were compared at 0.05 and 0.01 level of significance.

Results: Analysis of T student showed that Rely x was statistically significant greater than Nexus 2 in bonding to enamel at significance level of 0.05 and 0.01. The mean bond strength (Kg/inch²) obtained for Rely x was (9.82) and for Nexus 2 (2.98). However, the analysis of paired t-test for bond strength to dentin showed that there was no statistically significant difference between Rely x and Nexus 2.

Conclusion: Within the limitation of this study

• Bond strength values of Rely x to enamel were significantly higher.
• There was no statistically significant difference in bond strength to dentin for Rely x and Nexus 2.