Shear Bond Strength Of Ceramic Bracket With Porcelains Which In Different Surface Treatment

Objective: To evaluate the shear bond strength(SBS)between ceramic brackets and different porcelains,the surfaces of which were treated with three different methods.Methods: The surfaces of four kinds of specimens,i.e.PFM,casting porcelain,zirconium porcelain and aggregation porcelain,were sandblasted(SB),etched by hydrofluoric acid(HFA),or treated by the combination of sandblast and HFA etching(SB+HFA).Then they were coated by silane coupling agent(SCA)and were bond with ceramic bracket.The specimens were incubated in 37 ℃ water bath for 24 h before the shear bond strength test.Scanning electron microscope(SEM)analysis was performed to observe surface roughness of the porcelains before bonding with the brackets and the adhesive residue and the damage extents on the surface after removal of brackets.Results: The shear bond strength of PFM,casting porcelain and aggregation porcelain were statistically different from zirconium porcelain(P<0.05).The shear bond strength of PFM and casting porcelain were no statistically significant difference(P > 0.05).However,there was no significant difference in the shear bond strength between PFM and casting porcelain.SEM showed the surface roughness and porosity were significantly increased after surface treatment compared with the untreated groups.The surface roughness of SB and SB+HFA groups was significantly higher than that of HFA group.No significant difference was found between SB and SB+HFA groups.The four kinds of porcelains treated with SB showed the least adhesive residue with the lowest adhesive residue index scored compared with other two treatments.Conclusion: Three kinds of surface treatment methods could satisfy the clinical needs of orthodontics.After the removal of ceramic bracket,the SB group showed the least adhesive residue on the surface of the porcelains.SB+HFA treatment did not increase the shear bond strength significantly.