Our aim was to compare the time required to complete the alignment of crowded maxillary anterior teeth (canine to canine) between Damon MX (Ormco, Glendora, Calif) and In-Ovation R (GAC, Central Islip, NY) self-ligating brackets.
Seventy patients from the first author's office were included in this randomized controlled trial by using the following inclusion criteria: nonextraction treatment on both arches, eruption of all maxillary teeth, no spaces in the maxillary arch, no high canines, maxillary irregularity index greater than 4 mm, and no therapeutic intervention planned involving intermaxillary or other intraoral or extraoral appliances including elastics, maxillary expansion appliances, or headgear. The patients were randomized into 2 groups: the first received a Damon MX bracket; the second was bonded with an In-Ovation R appliance, both with a 0.022-in slot. The amount of crowding of the maxillary anterior dentition was assessed by using the irregularity index. The number of days required to completely alleviate the maxillary anterior crowding in the 2 groups was investigated with statistical methods for survival analysis, and alignment rate ratios for appliance type and crowding level were calculated with the Cox proportional hazard regression. An analysis of each protocol was performed.
No difference in crowding alleviation was found between the 2 bracket systems. Higher irregularity index values were associated with the increased probability of delayed resolving of crowding.
The use of passive or active self-ligating brackets does not seem to affect treatment duration for alleviating initial crowding.