| In our investigation of orthodontic attachments, three types of ceramic brackets (Clarity™, 3M Unitek; MXi®, TP Orthodontics; Allure®, GAC; in addition to a metal bracket control group, Victory Series™, 3M/Unitek) were tested at 24 hours and 6 months for shear-peel bond strengths to composite resin. Ninety-six cylindrical samples were made using Z100™ restorative resin (3M). Forty-eight brackets of each type were bonded to both ends of air abraded resin composite samples with either Transbond™ XT (3M/Unitek) or Fuji ORTHO™ LC (GC America). One end was used for the 24-hour testing and the other end for the 6-month testing. Samples were stored in distilled water at 37°C for either 24 hours or 6 months and then tested for shear-peel bond strength using a Materials Testing Device (Zwick), with a crosshead speed of 0.5mm/min. The shear-peel bond strengths as a function of bracket type, adhesive type and storage time were analysed by a Split Unit Analysis of Variance and Duncan's multiple comparison test at a 5% level of significance. (Abstract shortened by UMI.)... |
