A Modified Photoactivation Protocol Using Two Simultaneous Light-Curing Units for Bonding Brackets to Enamel

Abstract

photoactivation for 10 s on each proximal face of the bracket at a time; Simultaneous: photoactivation for 10 s on both proximal faces of the bracket at the same time; One side-20s: photoactivation for 20 s at one proximal face of the bracket only; and One side-10s: photoactivation for 10 s only at one proximal face of the bracket. SBS was tested immediately or after 1000 thermal cycles. Adhesive remnant index (ARI) was classified. Data were subjected to two-way ANOVA and Student-Newman-Keuls' test (α = 0.05). Pooled means ± standard deviations for SBS to enamel (MPa) were: 10.2 ± 4.2 (CONTROL), 9.7 ± 4.5 (Simultaneous), 5.6 ± 3.1 (One side-20s), and 4.6 ± 1.9 (One side-10s). Pooled SBS data for immediate and thermal cycled groups were 6.3 ± 2.6 and 8.8 ± 5.2. A predominance of ARI scores 1-2 and 0-1 was observed for the immediate and thermally cycled groups, respectively. In conclusion, simultaneous photoactivation of the orthodontic cement using two light-curing units, one positioned at each proximal face of the bracket, yielded similar bonding ability compared to the conventional light-curing method. Photoactivation of the orthodontic cement at one proximal face of the bracket only is not recommended, irrespective of the light-curing time used.

Orthodontic bracket bonding to glazed full-contour zirconia

“… 19 In this study, no ceramic fractures were found, probably indicating that the exposure to water and temperature changes involved in thermocycling mainly affected the bond of the resin composite to the metal bracket base ( Table 4 ). 18 However, de Oliveira et al 26 reported that the bracket bond strength to enamel was significantly improved after thermocycling. Further studies are required to determine whether longer thermocycling regimens are needed.…”