Efficacy of Various Self-Etching, Self-Curing Cements on Dentin Bond Strength

Dual cured resin cements are utilized to lute various types of dental restorations. These cements may be utilized to bond the restoration directly to the dentin of the tooth surface. Objective: The purpose of this study is to determine the efficacy of resin cements where the self-curing element of the cements is the only mechanism of polymerization initialtion. Materials and Methods: Twenty bovine incisors were sectioned creating 60 dentin blocks. Surfaces were uniformly smoothed with 600 grit paper under irrigation and randomly assigned to one of six cement groups: RelyX Unicem (3M ESPE, Seefeld, Germany), Panavia21 (Kuraray Medical Inc., Okayama, Japan), PanaviaF2.0 (Kuraray Medical Inc.), MonoCem (Shofu Dental Corp. San Macros, CA), Multilink (Vivadent, Liechtenstein), and MaxCem Elite (Kerr Corp. Orange, CA). Ten specimens of each cement were bonded creating a 2.38mm column of resin,,according to manufacturer's instructions. Margins of the resin columns were carefully cleaned to remove any excess. Specimens were thermocycled, 2000 cycles (4°C and 54°C 30 sec dwell time). Specimens were subject to shear force, utilizing an Instron 5566 (Canton, MA) at a crosshead speed of 0.5 mm/min and the load at failure was recorded. Mean loads at failure (MPa+s.d.) were calculated and ANOVA with a Scheffe post-hoc test was utilized. Results: Mean shear forces at failure,were: Maxcem Elite 6.26 (+8.49), MonoCem 1.12 (+1.84), Multilink 4.4 (+6.20), Panavia F2.0 7.77 (+12.25), Panavia 21 11.54 (+11.33), and RelyX 3.65 (+4.10). Statistical analysis revealed no statistical difference between any of the six dual-curing cements when allowed to self cure. Conclusion: Weaker bond strengths, due to a lack of complete polymerization, since a light cure was not utilized. Follow-up testing on RelyX with light initiated polymerization, revealed a bond strength nearly four times stronger with (p<0.001) over letting the product self polymerize. These materials should be light cured whenever possible.