Contrary to an old belief, four corner curing does not provide more bond strength or polymerization in bonding of orthodontic metal brackets

Objectives: The study aimed to investigate the effect of direction light curing on bond strength and adhesive polymerization orthodontic metal brackets. Material Methods: In this in vitro investigation, 75 extracted human upper premolars were randomly divided into three groups according direction: Group A (20 s from occlusal side bracket), B (10 10 gingival), C (5 four corners bracket). After bonding, brackets subjected a shear (SBS) test performed with universal testing machine. Moreover, Fourier transform infrared spectroscopy (FTIR) analysis was used find ratio adhesives each group. Kruskal–Wallis statistical SBS FTIR data, respectively, at 0.05 level significance. Results: difference not statistically significant between ( P > 0.05). However, all where highest lowest belonged Groups B, respectively < Conclusion: Curing do increase their and/or polymerization.