Influence of Various Surface Conditioning Methods on Bonding Orthodontic Brackets to Porcelain Surface

Objective: To investigate the effects of different surface conditioning methods on shear bond strength (SBS) of metal brackets bonded to porcelain surfaces and the influence of silane coupling agent in altering the bond strength. Materials and methods: A total of 80 feldspathic porcelain specimens were used. They were divided into eight different groups based on different surface conditioning methods and combinations: Sandblasting (SAB), hydrofluoric acid (HFA), diamond bur (DB) and air abrasion (AA). Silane coupling agent was used in five groups. Metal brackets were bonded and subjected to SBS testing. The efficiencies between the five individual methods used were analyzed. ARI scoring was done after debonding. Results: The SBS range was between 3.19 and 14.38 (MPa) with a mean of 8.89 ± 3.25 (MPa). The difference between mean SBS between different groups was significant (p < 0.001). As compared to DB-based group (10.46 ± 0.69 MPa) the non-DB based group were lower (8.66 ± 3.40 MPa) but the difference was not significant (p > 0.001). When compared to AA group (9.03 ± 0.59 MPa) the non-AA group were lower (8.87 ± 3.46 MPa) but again the difference was not significant (p > 0.001). ARI score 0 was observed in 47 instances (58.8%), score 1 was observed in 25 instances (31.2%). Conclusion: The results indicated that surface conditioning alone without silanation produced significantly low SBS. Air abrasion followed by silanation produced favorable bond strength and might have the potential to replace alternative methods.