Treatment efficiency of conventional vs self-ligating brackets: Effects of archwire size and material

Introduction: In this prospective clinical study, we assessed the relative speed of archwire changes, comparing self-ligating brackets with conventional elastomeric ligation methods, and further assessed this in relation to the stage of orthodontic treatment represented by different wire sizes and types. Methods: The time taken to remove and ligate archwires for 131 consecutive patients treated with either self-ligating or conventional brackets was prospectively assessed. The study was carried out in the orthodontic department of a district general hospital in the United Kingdom. The main outcome measure was the time to remove or place elastomeric ligatures or open/close self-ligating brackets for 2 matched groups of fixed appliance patients: Damon2 self-ligating bracket (SDS Ormco, Orange, Calif) and a conventional mini-twin bracket (Orthos, SDS Ormco). The relative effects of various wire sizes and materials on ligation times were investigated. The study was carried out by 1 operator experienced in the use of self-ligating and conventional brackets. Results: The Damon2 self-ligating system had a significantly shorter mean archwire ligation time for both placing (P < .001) and removing (P < .01) wires compared with the conventional elastomeric system. Ligation of an archwire was approximately twice as quick with the self-ligating system. Opening a Damon slide was on average 1 second quicker per bracket than removing an elastic from the mini-twin brackets, and closing a slide was 2 seconds faster per bracket. This difference in ligation time between the Damon2 and the conventional mini-twin brackets became more marked for larger wire sizes used in later treatment stages. Conclusions: The type of bracket and the size of wire used are statistically significant predictors for speed of ligation and chairside time. The self-ligating system offered quicker and arguably more efficient wire removal and placement for most orthodontic treatment stages.