Comparative Evaluation of Four Adhesive Luting Resin Cements

Objectives: To investigate 1) the bonding efficiency to enamel/dentin and 2) mechanical characteristics of four adhesive luting resin cements. Materials and Methods: Products: Bistite II DC (BI) and M-Bond (MB), Tokuyama, Japan, Panavia F (PA), Kuraray, Japan, and Super-Bond C&B (SB), Sun Medical, Japan. Shear bond strengths (SBS) to human enamel and dentin were determined (n=6) on flat ground proximal tooth surfaces. The cements were applied according to instructions. A split cylindrical Teflon mold (3.5 by 2 mm) was placed for application of the mixed pastes. The cements were dark-cured only and immersed in 37 C water for 24 h prior to shear loading (1 mm/min). Modes of failure were determined by light microscopy, dentin hybridization depth by SEM. For flexural strength and modulus evaluation 6 specimens/cement (25 x 2 x 2 mm) were dark-cured for 30 min and immersed in 37 C water for 24 h prior to testing. Statistical data treatment: one-way ANOVA and Duncan's post hoc test at a=0.05. Results: SBS (MPa) on enamel/dentin: BI 19.8/11.0, MB 13.4/13.6, PA 23.4/20.1, SB 20.9/20.0. Duncan ranking of SBSs enamel/dentin: MB < BI,SB < SB,PA/BI < MB < SB,PA. All failures were in resin or tooth substance. Dentin hybrid layer thickness (mm): BI 1.4, MB 1.7, PA 2.0, SB 2.8. Flexural strength (MPa) by significant difference; MB 43, BI 46 < SB 58, PA 64. Modulus (GPa) by significant difference: SB 1.5, MB 2.0 < PA 6.2 < BI 7.2. Conclusions: The four luting resins are considered clinically effective. From the glass-filler loaded types BI and PA the latter one is preferable due to the higher bonding strength. The PMMA-bead loaded types are promising. Their low stiffness ensures good strain absorption capacity. Due to handling characteristics MB is definitively preferable.