Tuesday, May 11, 2010

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

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

Journal of Orthodontics, Vol. 37, No. 1, 37-42, March 2010 doi:10.1179/14653121042858
© 2010 British Orthodontic Society

Mariana Marquezan, Thiago Lau, Carina Rodrigues, Eduardo Sant'Anna, Antônio Ruellas, Marcela Marquezan and Carlos Elias Department of Pedodontics and Orthodontics, Federal University of Rio de Janeiro (UFRJ), Brazil
Federal University of Santa Maria (UFSM), Brazil
Militar Engeneering Institute (IME), Rio de Janeiro, Brazil

Address for correspondence: Dr Antônio Carlos Oliveira Ruellas, Federal University of Rio de Janeiro, Brazil. E-mail: antonioruellas@yahoo.com.br
Objective: To evaluate the shear bond strength of orthodontic brackets bonded to bovine enamel using a new curing appliance composed of an LED cluster.
Design: In vitro, laboratory study.
Materials and methods: 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.
Results: 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.

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