Comparison of the effects of different adhesive systems on resin bond strengths in intraoral repair of zirconia-based ceramics

The aim of this in vitro study was to investigate the effects of different adhesive systems on resin bond strength in the intraoral repair of zirconia-based ceramic restorations. In vitro study, disc-shaped zirconia (Vita YZ HT) (n=40) and feldspathic ceramic (Vita VM 9) (n=40) specimens were prepared to imitate different fracture types in zirconia-based restorations. Different surface roughening processes were applied to the zirconia and feldspathic ceramic specimens, zirconia was silica-coated (Cojet) and feldspathic ceramic was etched with 9.5 % hydrofluoric acid. The total number of specimens used in this study was 84 (N=84), and four were used for SEM testing to examine the surface topography after roughening. The 80 specimens were divided into four subgroups for each ceramic group based on the different adhesive systems applied (n=10) (Group M (Monobond Plus), Group B (Bisco porcelain primer + Bonding resin), Group C (Clearfil Quick Bond), Group G (GC Multi Primer + G-Premio Bond)). After the application of different adhesive systems, composite resin was applied to all specimens. The specimens were stored in distilled water (37°C, 24h) and thermocycled (5–55 °C, 10000 cycles). Subsequently, all specimens were subjected to shear bond strength testing (1 mm/min). Fracture surfaces were analyzed using light microscopy and scanning electron microscopy (SEM). Data were analyzed using Minitab V14, Shapiro-Wilk, and Tamhane's T2 test (p<0.05). The maximum SBS values for fedspathic and zirconia ceramics were noted in Group B (15.314 ± 3.531MPa) and Group G (13.793 ± 2.384MPa), respectively. Feldspathic ceramic in Group B had the highest frequency of cohesive failure (100%). Zirconia ceramics in Group G had the maximum frequency of mixed failure (70%). Statistical analyses showed that different adhesive systems had a significant effect on shear bond strength values depending on the type of ceramic used (p< 0.05). The use of different adhesive systems is recommended for intraoral repair of zirconia-based restorations, depending on the material at the fracture site.