Comparative Evaluation of Tensile Bond Strength of Nickel-Chromium Alloy to Dental Enamel Using Different Resin Cements-An in Vitro Study

Aim: The aim of this study was to evaluate and compare the tensile bond strength of nickel-chromium alloy to dental enamel by using four different resin cements.
Materials and Methods: 40 extracted central incisor teeth embedded in acrylic blocks were flattened not to expose dentin.Wax rectangular blocks of 5mmlength, 5 mm width and 1 mm height with a loop were invested and casted using Nickel-Chromium alloy by conventional induction casting method and sandblasted. Then casted rectangular blocks and 40 tooth embedded acrylic samples were divided into four groups (10 each) and cemented to tooth enamel following manufacturer's instructions as; GroupAcemented using RelyX U200, Group B cemented using Smartcem 2, Group C cemented using Multilink Speed and Group D cemented using Multilink N and then stored in artificial saliva for 24 hours. The direct pull tensile test was carried out on Universal Testing Machine at cross head speed of 0.5mm/min.
Results: One way ANOVA showed a highly statistically significant (p<.01) difference between all the four resin cements. Post Hoc Tests- Multiple comparisons showed highly statistically significant (p<0.01) difference between RelyX U200: Multilink N, Smartcem 2: Multilink Speed, Smartcem 2: Multilink N, Multilink Speed: Multilink N. Difference between RelyX U200 : Smartcem 2 and RelyX U200 : Multilink Speed was statistically significant(p< 0.05).
Conclusion: Self etch resin cement (Multilink N) showed maximum mean tensile bond strength as compared to self-adhesive resin cements (Smartcem 2, RelyX U200 and Multilink Speed). Clinically the greatest advantage of self-adhesive cements is the easy and fast application technique. But this time saving technique is not as effective as selfetch resin luting agents. The presumed benefit of saving time with self-adhesive luting agents may only be realized at the expense of compromising bond strength.