Does the design of self-ligating brackets show different behavior in terms of friction?

Aim: This in vitro study evaluated the friction generated by aligned stainless steel conventional brackets, self-ligating Damon MX brackets, Time3 brackets, Vision LP brackets, and low-friction Slide ligatures coupled with various stainless steel, nickel-titanium (Ni-Ti), and beta-titanium (TMA) archwires.

Methods: All brackets had a 0.022-inch slot; the orthodontic archwires were 0.014-inch Ni-Ti, 0.016-inch Ni-Ti, 0.014 x 0.025-inch Ni-Ti, 0.018 x 0.025-inch Ni-Ti, 0.017 x 0.025-inch TMA, 0.019 x 0.025-inch stainless steel, and 0.019 x 0.025-inch Ni-Ti. Each bracket-archwire combination was tested 10 times.

Results: Coupled with 0.014-inch Ni-Ti and 0.016-inch Ni-Ti archwire, conventional brackets generated the greatest friction, while Damon MX and Vision LP brackets generated the lowest (P < .05). No significant difference was observed between Time3 brackets and Slide ligatures. Coupled with all the rectangular archwires, Victory Series brackets, Slide ligatures, and Vision LP self-ligating brackets generated significantly lower friction than Time3 and Damon MX self-ligating brackets (P < .05).

Conclusion: These findings suggest that self-ligating brackets are a great family of brackets that, in vitro, can generate different levels of friction when coupled with thin, thick, rectangular, or round archwires. Clinical conclusions based on our results are not possible, due to the limitations of the experimental conditions.