Shear bond strengths of orthodontic brackets with a new LED cluster curing light

To evaluate the shear bond strength of orthodontic brackets bonded to bovine enamel using a new curing appliance composed of an LED cluster.

In vitro, laboratory study.

Standard edgewise maxillary central incisor metal brackets (0.022'' slot) were bonded to 60 bovine incisors which were arranged in a parabola, simulating the dental arch. The arches were randomly allocated to one of five groups: three experimental groups in which a half arch was cured using the Whitening Lase Ortho LED Cluster light for 10, 20 and 40 s (EG10s, EG20s, EG40s) and two control groups. Control group 1 (CGH) were cured using a halogen light for 20 s and control group 2 (CGL) were cured using a conventional LED light for 20 s per tooth. A shear debond test was performed using an EMIC machine and the results were analyzed by ANOVA and post hoc Tukey multiple comparisons. The Adhesive Remnant Index (ARI) was determined at 10x magnification.

The one-way ANOVA showed a statistically significant difference between the groups (P<0.001). The post hoc Tukey comparison showed that the bond strength for group EG10s was significantly lower than both the control groups CGH (P<0.001) and CGL (P<0.001). There was no significant difference between the bond strengths for groups EG10s and EG20s (P = 0.100). Neither were there any statistically significant differences detected between groups EG20s, EG40s, CGL and CGH (P>0.05).The ARI analysis revealed a higher frequency of score 2 for groups CGL, EG10s, EG20s, a higher frequency of score 0 and 1 for the CGH group and a score of 1 was most frequent for the EG40s group.

The Whitening Lase Ortho LED Cluster light shows promise when bonding a half dental arch with a curing time of 40 s.