ABSTRACT:
Objective: The purpose of this study was to evaluate the effect of two surface treatment protocols and aging on the shear bond strength values of monolithic zirconia and lithium di-silicate glass ceramic.
Materials and methods: Eighty ceramic specimens were separated into groups to evaluate shear bond strength using a universal testing machine. There were two main groups based on ceramic material: lithium disilicate glass ceramic (IPS e.max CAD) and monolithic zirconia (IPS e.max ZirCAD prime). Each main group was further subdivided into two surface treatment subgroups of 20 specimens each: (1) hydrofluoric acid etching with silane coupling agent (2) sandblasting. Additionally, each surface treatment subgroup was split into two classes: before and after thermocycling. All ceramic restorations were bonded using a light-cured resin cement. Shear bond strength data was collected for statistical analysis.
Results: Thermocycling significantly decreased the SBS mean values concerning zirconia ceramic with sandblasting from (13.01 ± 3.89) to (3.12 ± 0.96), while with hydrofluoric acid mean values from (9.8 ± 3.0.) to (2.36 ± 0.35). Zirconia ceramic revealed significantly lower shear bond strength than lithium disilicate in all groups P<0.05.
Conclusion: Thermocycling decreased the shear bond strength of both ceramics, regardless of the type of surface treatment applied. Sandblasting surface treatment was better than hydrofluoric acid with silane when applied to zirconia ceramic. IPS ZirCAD prime ceramic still revealed weaker bond stability in comparison with IPS e.max CAD ceramic.