SHEAR BOND STRENGTH OF BRACKETS ON BONDING TO TREATED AMALGAM SURFACES
The field of orthodontics has improved many folds since its advent in 1900 century. Orthodontic bonding to enamel surface has massively improved the control of clinician in an effort to settle teeth in an ideal occlusion. Amalgam fillings have been in use since the development of the field of dentistry. Orthodontist more often than not comes across amalgam as a surface to bond bracket in term of fixed orthodontic therapy. The strength of bond between orthodontic bracket and amalgam has to improve, in order to insure the most important phase of orthodontic treatment that is orthodontic bonding.
The aim of this study was to compare mean shear bond strength of orthodontic brackets on sandblasted versus diamond bur roughened amalgam surfaces.
This randomized control trial was performed in the Department of Orthodontics, FMH College of Medicine and Dentistry Lahore. Sixty extracted human maxillary premolars and molars were used. They were randomly divided into two study groups of 30 teeth. In group-I, brackets were bonded to amalgam using sandblasting with 50 um alumina particles. In group-II, brackets were bonded after amalgam surface was roughened with a diamond bur. Brackets were debonded using AGS-J SHIMADZU 5 KN universal testing machine with cross head speed of 1mm/min and shear bond strength was measured along with it.
Shear bond strength of sandblasted group was higher than the diamond roughened group. In this in vitro study, it was concluded that the shear bond strength of sandblasted group on bonding stainless steel brackets to amalgam surface was significantly higher than that obtained with diamond bur roughening.