EFFECT OF DIFFERENT BONDING PROTOCOLS OF CERAMIC BRACKETS WITH HIGH POWER LED ON THE BOND STRENGTH AND DEGREE OF CONV
Keywords: Shear Strength. Spectroscopy, Fourier Transform Infrared. Dental Enamel. Orthodontic Brackets.
ERSION.
Objective: To analyze the effect of different photoactivation protocols on shear bond strength (SBS) of ceramic brackets (monocrystalline and polycrystalline) bonded to enamel and on the degree of conversion (DC) of an orthodontic resin using the high-power photoactivator Valo Cordless® (Ultradent). Methodology: 80 crowns of bovine incisors were randomly distributed in 8 groups (n=10), 40 from Group 1 (monocrystalline brackets) and 40 from Group 2 (polycrystalline brackets). After the surface treatment with phosphoric acid (15 seconds) and Primer Transbond XT® (3M Unitek), ceramic brackets were bonded to the tooth enamel with Transbond XT® resin (3M Unitek) using 4 different photoactivation protocols according to the factors "photoactivated faces" (center/vestibular; mesial/distal and cervical/incisal) and "photoactivation time" (3 or 6 seconds). The shear test (100KgF, 1mm/min) was performed after storage of the samples for 4 months (distilled water, 37°C). Using the same photoactivation protocols, 80 resin discs (0,1 mm thick and 5 mm diameter, on average) were made for DC analysis. The SBS (MPa) and DC (%) data will be evaluated descriptively and through Student's T-test, two-way ANOVA and the Tukey test. The union failures will be classified according to the Adhesive Remnant Index (ARI), analyzed descriptively and through the Kruskal-Wallis test.