3D slot roughness of seven contemporary plastic brackets

Objectives: To evaluate the roughness of slots of seven orthodontic plastic brackets. Methods: Seven plastic bracket brands (Brillant, Elegance, Spirit MB, Silkon plus, Avalon, OrthoFlex, Aesthetik-line) were included in the study. The bottom of each slot of every bracket was selected for evaluation and pictures were taken by optical microscopy at magnification (20x) for a general estimation of the roughness. Then the roughness parameters (Ra, Rq, Rt, Rz) of every slot were defined in a 3D optical profilometer in a higher magnification and 3D-images were obtained. Results: Optical microscope pictures revealed a variety of textural characteristics of slots for the brackets tested. Metallic slots presented grooves and striations whereas plastic slots presented peaks and pits. OrthoFlex presented the highest Ra and Rq value, statistically higher than the other brackets tested. Elegance bracket exhibited the second higher Rq value, which statistically was higher among the other brackets. Brillant, Silkon and Elegance presented the highest Rz and Rt values, which were statistically significant higher than the other brackets, followed by Othoflex which presented statistically significant higher values compared to Avalon, Aesthetik line and Spirit MB brackets. Conclusions: 3D-images and roughness parameters of slots represented significantly different among the tested brackets. Additional of metallic slot to some of tested brackets exhibited no statistically decrease in average of roughness with plastic slots except OrthoFlex slot gave high roughness than other brackets. Avalon , Aesthetik line and Spirit MB exhibited low roughness parameters.