Many studies on in-vitro orthodontic bond strength fail to report test conditions that could significantly affect their outcomes
INTRODUCTION The aims of this study were to systematic ally review the available literature regarding in-vitro orthodontic shear bond strength testing and to analyze the influence of test conditions on bond strength .
The influence of orthodontic bracket base design on shear bond strength.
Many bracket base design s and adhesive material s are in clinical use today . Bases have evolved from perforated metal bases to the present foil mesh bases , and treatments range from none , to spraying metal alloy onto the base , to the most common treatment of microetching . The purpose of this study was to determine the effect of orthodontic bracket base design on mean shear bond strength 1 hour or 24 hours after bonding . For each time group , 12 specimens of 6 types of metal brackets were bonded to bovine incisors with Transbond XT ( 3 M Unitek , Monrovia , Calif ) light-cured composite resin . Brackets were debonded 1 hour or 24 hours later , and the shear bond strength was recorded . Six debonded brackets of each type from each time group were selected at r and om and s and blasted . All the teeth were cleaned , and half were rebonded with used brackets , and half were rebonded with new brackets . Bond strength was measured again , 1 hour or 24 hours later . Representative specimens were inspected under the scanning electron microscope . Bracket base design significantly affected mean shear bond strength . Speed ( 60-gauge , microetched foil-mesh base ; Strite Industries , Cambridge , Ontario , Canada ) had the highest bond strength at 1 hour ; followed by Time ( machined , integral , microetched base with mechanical undercuts ; American Orthodontics , Sheboygan , Wis ) ; American Master Series ( 80-gauge foil-mesh base ; American Orthodontics ) ; Ovation Roth ( 80-gauge layered onto 150-gauge , microetched foil-mesh base ; GAC , Central Islip , NY ) ; Orthos Optimesh XRT ( 100-gauge microetched foil-mesh base ; Ormco , Orange , Calif ) ; and , finally , the nickel-free brackets ( injection molded , 100-gauge , microetched , foil-mesh base ; World Class Technology , McMinnville , Ore ) . The 24-hour results were similar except that Time had the highest mean shear bond strength ( ANOVA , P < .05 ) . Chairside s and blasting significantly affected the 1-hour , but not the 24-hour , mean shear bond strengths ( ANOVA , P < .05 ) . S and blasting appears to be an effective method of cleaning bracket bases before rebonding
Many studies on in-vitro orthodontic bond strength fail to report test conditions that could significantly affect their outcomes
INTRODUCTION The aims of this study were to systematic ally review the available literature regarding in-vitro orthodontic shear bond strength testing and to analyze the influence of test conditions on bond strength .