Evaluation of different surface treatment on shear bond strength of composite to E max porcelain (in-vitro)

Background and Aim: The aim of this study was to investigate the shear bond strengthof composite to Emax porcelain using different methods of ceramic surface preparation (in vitro). Material and Methods: In this laboratory study, 36 porcelain disks were made and divided into four equal groups. The first group was prepared by sandblasting with 50 micron alumina particles, in the second group received porcelain level of 9.5% HF for 20 seconds. Group three was first sandblasted and then by HF 9.5% and the fourth group was first prepared by HF 9.5% and then by sandblasting and the same silane, bonding and composite were applied to 36 samples. Finally, their shear bond strength test was performed. The mean shear bond strength in MPa was analyzed by ANOVA (a = 0.05) and Tukey test. The fracture pattern of the samples was examined by stereomicroscope Results: The  highest mean shear bond streght of the groups was related to sandblast +etching wigh HF(38.52±6.19 MPa),  etching with HF+ sandblast (26.8±3.58 Mpa), etching with HF(23.28±4.03 Mpa), respectively and the least streght was reffered to sandblast (18.87±2.15 Mpa). The shear bond streght of composite to  Emax  porcelain in sandblast group was lower  than  sandblast and etching with HF group (p<0.001) and etching with HF and sandblast group (p=0.002). This value was significantly higher in sandblast with HF compare to etching with HF group (p<0.001).  The Maximum Failure in all groups  was cohesive type. Conclusion:  The highest mean shear bond strength of the groups was related to sandblast + etching with HF etching with HF + sandblasting, etching with HF and sandblasting. The most common type of failure in all groups was Cohesive.