Bond strength of 4 orthodontic adhesives used with a caries-protective resin sealant

Introduction: The purpose of this study was to investigate the shear peel bond strength (SPBS) and resin remnant retention after removal of orthodontic brackets bonded with 1 of 4 orthodontic adhesives (Transbond XT [3M/Unitek, Monrovia, Calif], Blugloo [Ormco Corp, Glendora, Calif], Light Bond [Reliance Orthodontic Products, Itasca, Ill], and APC Plus [3M/Unitek]) applied over a filled, resin sealant (ProSeal [Reliance Orthodontic Products]). Methods: Extracted premolars were first acid etched and then coated with the sealant used as a primer. This was followed by cementation of a stainless steel orthodontic bracket to the buccal surface with 1 of the 4 adhesive systems. Two adhesive systems (Transbond XT and Blugloo), without the filled sealant applied, were used as references. All specimens were stored in deionized water at 37°C for 30 days, thermocycled for 24 hours at 30-second intervals between 10°C and 50°C water baths, and debonded with a universal testing machine. Results and Conclusions: The 4 adhesive-sealant combination groups had mean SPBS values slightly lower than the 2 adhesive-only reference systems, but all were greater than 10 MPa (range, 10.1-15.9 MPa), which is considered a clinically acceptable bond strength. ANOVA showed a statistically significant difference (P <0.05) in mean SPBS among the 4 adhesive-sealant combinations. The most frequent site of bond failure at debonding for the adhesive-sealant combinations was within the adhesive.