Surface Roughness of Ceramic-Resin Composites After Femtosecond Laser Irradiation, Sandblasting or Acid Etching and Their Bond Strength With and Without Silanization to a Resin Cement

Abstract

Objectives: The aim of this study was to investigate the effects of femtosecond laser irradiation, sandblasting, or acid etching treatments on the surface roughness of ceramic-resin composites and also shear bond strength (SBS) with and without silanization to a resin cement. Methods: Samples of Vita Enamic (VE; Vita Zahnfabrik, Bad Sackingen, Germany) and Lava Ultimate (LU; 3M ESPE, Seefeld, Germany) were classified into control (no treatment), sandblasting, hydrofluoric acid, and femtosecond laser groups (n= 30). Surface roughness was determined using two-dimensional contact profilometry. Surface topography was evaluated using a three-dimensional contact profilometer and a scanning electron microscope. Then groups were divided into two subgroups with similar surface roughness values, including control (C), control + silane (C-S), sandblasting (SB), sandblasting + silane (SB-S), hydrofluoric acid (HF), hydrofluoric acid + silane (HF-S), femtosecond laser (FS), and femtosecond laser + silane (FS-S) groups (n= 15). Panavia F 2.0 resin cement was applied to the sample surfaces using an SDI SBS rig (SDI Limited, Bayswater, Australia). The SBS test was performed after water storage (24 h, 37 degrees C) and thermocycles (2000 cycles, 5 degrees C to 55 degrees C), and failure modes were evaluated. Results: The highest surface roughness was observed in the FS group, and the highest SBS was observed in the FS-S group for both VE and LU (p<0.001). Silanization improved the SBS of VE significantly (p<0.001) in all surface treatments but did not improve that of LU except in the FS group (p=0.004). There was a significantly moderate negative correlation in the VE/SB group (p=0.012) and a moderate positive correlation in the VE/HF group (p=0.049). Conclusions: Femtosecond laser irradiation was found to be more effective than sandblasting or acid etching in increasing the surface roughness, and it was also the most effective surface treatment with silanization on the SBS of a resin cement to the ceramic-resin composites.