Adherence strength of brackets glued with different LED equipments

Objectives: The aim of this study was to evaluate the adherence strength of metal brackets glued to tooth enamel and light-cured by 4 types of equipment: the control group, with halogen light (Optilux Demetron), and 3 other (Ortholux 3M Unitek, Ultraled XP Dabi, and Radii SDI). The study investigated if brackets glued to tooth enamel with LED equipment would achieve the minimum adherence strength required in orthodontic treatment.

Methods: We used 40 bovine teeth (n = 40), divided into 4 groups of 10, for each light-curing device. Surface analysis tests were performed before the brackets were glued to the teeth. After the gluing, shearing tests were performed with an assay machine of universal traction adapted to apply an ‘ungluing' charge (speed of 0.5 mm/min). The machine was connected to a computer.

Results: The Ortholux 3M Unitek LED curing device obtained the highest bracket adherence values in shearing, statistically different from values showed by (in decreasing order) the Ultraled XP Dabi LED curing device (p < 0.05) and the Radii SDI LED curing device (p < 0.05). The values shown by the Ortholux equipment and by the Optilux equipment were statistically similar. The Optilux Demetron light-curing device was statistically more effective than the Ultraled XP equipment (p < 0.05) and the Radii SDI equipment (p < 0.05), whose statistics were similar.

Conclusions: It is recommended in dental practice to glue brackets with the use of LED equipment with proven good performance, such as 3M Unitek, or to continue to use halogen light-curing equipment.