Purpose: Since adhesion of the restorative materials to pre-polymerized or aged resin composites presents a challenge to the clinicians, existing restorations are often removed and remade prior to cementation of fixed dental prostheses (FDPs). This study evaluated bond strength of non-aged and aged resin composite to an indirect resin composite and pressed glass ceramic using two resin cements.
Materials and Methods: Disk-shaped specimens (diameter: 3.5, thickness: 3 mm) (N = 160) produced from a microhybrid resin composite (Quadrant Anterior Shine) were randomly divided into eight groups. While half of the specimens were kept dry at 37 degrees C for 24 h, the other half was aged by means of thermocycling (6000 times, 5 degrees C to 55 degrees C). The non-aged and aged resin composites were bonded to a highly filled indirect composite (Estenia) and a pressed glass ceramic (IPS Empress II) using either a photopolymerizing (Variolink Veneer) or a dual-polymerizing (Panavia F2.0) resin cement. While cementation surfaces of both the direct and indirect composite materials were silica coated (30 mu m SiO2, Co Jet-Sand) and silanized (ESPE-Sil), ceramic surfaces were conditioned with hydrofluoric acid (20 s), neutralized, and silanized prior to cementation. All specimens were cemented under a load of 750 g. Shear force was applied to the adhesive interface in a universal testing machine (1 mm/min). Failure types of the specimens were identified after debonding.
Results: Significant effects of aging (p <0.05), restorative material (p <0.05), and cement type (p <0.05) were observed on the bond strength (3-way ANOVA). Interaction terms were also significant (p <0.05) (Tukey's test). After aging, in terms of bond strength, indirect composite and pressed glass ceramic in combination with both cements showed no significant difference (p > 0.05). Both indirect composite (24.3+/-5.1 MPa) and glass ceramic in combination with Variolink (22+/-9 MPa) showed the highest results on non-aged composites, but were not significantly different from one another (p > 0.05). On the aged composites, indirect composite and glass ceramic showed no significant difference in bond strength within each material group (p > 0.05), with both Panavia (17.2+/-6 and 15+/-5.5 MPa, respectively) and Variolink (19+/-8, 12.8+/-5.3 MPa, respectively), but in all groups, glass ceramic-Variolink on aged composite revealed the lowest results (12.8+/-5.3 MPa). Among all groups, predominantly cohesive failures were observed in the indirect resin composite substrate (79 out of 80) as opposed to the ceramic (18 out of 80) (p <0.05) (Chi square).
Conclusion: Regardless of the resin cement type, considering the bond values and the failure types, the adhesion quality of indirect composite cemented to non-aged and aged resin composite was superior with both cements compared to that of pressed glass ceramic.
- glass ceramic
- microhybrid composite
- silica coating
- surface conditioning
- SURFACE CONDITIONING METHODS
- LITHIUM DISILICATE CERAMICS
- PORCELAIN VENEERS
- AGING CONDITIONS