Effect of light-emitting diode curing tip distance on shear bond strength in metal, ceramic and polycarbonate orthodontic brackets: An in vitro study.

Adequate shear bond strength between orthodontic brackets and enamel is essential for successful treatment. However, the effect of LED curing tip distance on different bracket materials remains unclear. Therefore, it is of interest to evaluate the shear bond strength of stainless-steel, polycarbonate and monocrystalline ceramic and polycrystalline brackets at varying LED curing distances. Two hundred premolars were divided by bracket type and curing distances (0, 6, 8, 10 and 15 mm) and bond strength was tested using a universal testing machine. Results showed high bond strength at 0 mm with a significant reduction as distance increased, with stainless-steel and ceramic brackets maintaining clinically acceptable values while polycarbonate brackets showed reduced strength at greater distances. Both bracket material and curing distance significantly influenced shear bond strength, emphasizing the need to minimize curing distance for optimal bonding performance.