RESUMEN
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[registered sign] [Biodental Technologies], Filtek Z250[registered sign] [3M-ESPE], Prettau-Anterior[registered sign] [Zirkonzhan, Germany]] were prepared as blocks [10×10×4 mm3] according to the manufacturer's instructions. Lithium disilicate ceramic blocks were also constructed and bonded to core specimens with two dual curing luting resin cements [Duo-Link[registered sign] [Schaumburg, IL], Bifix QM[registered sign] [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 +/- 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