24-hour shear bond strength of metal orthodontic brackets bonded to porcelain using various adhesion promoters

Clinically, orthodontists are often faced with the difficulties of bonding to porcelain crowns, veneers, or bridges. Traditional methods of dealing with this are often time-consuming and generally esthetically unacceptable to patients. Current interest involves the use of organosilane primers with or without NTG-GMA and BPDM resins to aid in chemically bonding porcelain with traditional orthodontic adhesives. This study compared the bond strength of three types of adhesion promoters: Ormco Porcelain Primer (OR) (Ormco Corp., Glendora, Calif.), All-Bond2 (AB2) (Bisco Dental Products, Inc., Itasca, Ill.), and Scotchprime Ceramic Primer (SP) (3M, St. Paul, Minn.) with two orthodontic adhesives: Phase II (Reliance, Inc., Itasca, Ill.) and Rely-a-bond (Reliance, Inc., Itasca, Ill.). Eighty ceramometal samples were fabricated and hydrated for 1 week in distilled water before bonding. Next, the samples were etched with 2.5 % HF acid for 90 seconds, rinsed and upper central incisor metal orthodontic brackets were bonded with the various primers and adhesives. After 24 hours they were sheared off with an MTS machine at at rate of 0.5 mm/min, and the bond strength was measured. The mean shear bond strengths (MPa) with Phase II were as follows; Control 0.44 (sigma = 0.22), AB2 8.40 (sigma = 3.61), OR 13.31 (sigma = 5.79), SP 13.53 (sigma = 3.34). With Rely-a-bond, the shear bond strengths were Control 0.41 (sigma = 0.67), AB2 4.34 (sigma = 1.88), OR 9.73 (sigma = 4.58), and SP 12.40 (sigma = 3.05).(ABSTRACT TRUNCATED AT 250 WORDS)