Tensile bond strength of ceramic orthodontic brackets bonded to porcelain surfaces

The aim of this study was to compare various surface treatment methods to d efine the procedure that produces adequate bond strength between ceramic br ackets and porcelain. The specimens used in this study, 60 porcelain tabs, were produced by duplication of the labial surface of a maxillary first pre molar. The 6 different preparation procedures tested were: (1) sandblasting with 50 mum aluminum oxide in a sandblasting device, (2) application of si lane to the porcelain and the bracket base, (3) sandblasting followed by ap plication of silane, (4) acid etching with 9.6% hydrofluoric acid, (5) acid etching with 9.6% hydrofluoric acid followed by application of silane, and (6) sandblasting followed by application of 4-Meta adhesive. The ceramic b rackets were bonded with no-mix orthodontic bonding material. A bonding for ce testing machine was used to determine tensile bond strengths at a crossh ead speed of 0.5 mm per second. The results of the study showed that porcel ain surface preparation with acid etching followed by silane application re sulted in a statistically significant higher tensile bond strength (P <.05) . Sandblasting the porcelain surface before silane treatment provided simil ar bond strengths, but sandblasting or acid etching alone were less effecti ve. Silane application was recommended to bond a ceramic bracket to the por celain surface to achieve bond strengths that are clinically acceptable.