Microtensile Bond Strength of Three Restorative Core Materials with IPS e.max Press Ceramic by Two Resin Cements

Objectives: The aim of this study was to compare the microtensile bond strengths (&micro; TBS) of three core materials with one lithium disilicate reinforced ceramic using two resin cements. Methods: Three core materials (Nulite F&reg; (Biodental Technologies), Filtek Z250&reg; (3M-ESPE), Prettau-Anterior&reg; (Zirkonzhan, Germany)) were prepared as blocks (10&times;10&times;4 mm3) according to the manufacturer&rsquo;s instructions. Lithium disilicate ceramic blocks were also constructed and bonded to core specimens with two dual curing luting resin cements (Duo-Link&reg; (Schaumburg, IL), Bifix QM&reg; (VOCO, Cuxhaven, Germany)). Micro-bar specimens were prepared and loaded in tension to determine the &micro; TBS Failure modes were classified by scanning electron microscope (SEM). Data were analysed using two-way ANOVA and Tukey HSD test. Results: The &micro; TBS varied significantly depending on the core materials and resin cements used (P< 0.05). The &micro; TBS of Bifix QM was significantly higher than of Duo-Link in all core materials. The &micro; TBS of zirconia core was significantly higher than of both composite cores with both resin cements. There were no statistically significant differences among Nulite F and Filtek Z250 (P> 0.05). The highest bond strength was obtained between zirconia core and Bifix QM (45.3 &plusmn; 6.7 MPa). Conclusion: In vitro &micro; TBS of glass ceramic blocks bonded to zirconia core material showed higher bond strength values than resin-based core material, regardless of the resin cement type used.