Introduction
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.
Methods
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.
Results
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.
Conclusions
The use of passive or active self-ligating brackets does not seem to affect treatment duration for alleviating initial crowding.
Editor’s summary
In the last decade, several new appliance systems have been developed; among the more prominent are passive and active self-ligating brackets. For most of these appliances, evidence supporting their marketed characteristics is lacking. Thus far, most prospective and randomized clinical trials demonstrated no difference between conventional and self-ligating brackets for the rate of tooth movement. The purpose of this study was to compare the time required to complete the alignment of crowded maxillary anterior teeth (canine to canine) between passive and active self-ligating brackets.
Seventy patients were included in this randomized controlled trial (RCT), with their selection based on the following criteria: nonextraction treatment plan, fully erupted dentition, no spacing in maxillary arch, no high canines, an irregularity index greater than 4 mm, no extraoral appliances or elastics, and no maxillary expansion appliances. The active self-ligating group was bonded with the Roth prescription In-Ovation R bracket, and the passive self-ligating group received the high-torque version of the Damon MX bracket. The amount of crowding was assessed with Little’s irregularity index.
Archwire sequence was the same for both treatment groups: 0.014-in Damon arch form copper-nickel-titanium followed by 0.016 × 0.025-in Damon archform copper-nickel-titanium. The 70 patients who met the inclusion criteria were randomized to receive either an active or a passive self-ligating appliance. The time for alignment of the maxillary 6 anterior teeth only for each patient was calculated in days.
The conclusions of this RCT were consistent with the results of other studies and provide an additional piece of what is becoming a complex but useful picture. Active and passive self-ligating brackets did not show a difference in treatment duration for correcting maxillary anterior crowding, although the degree of crowding did. The type of movement and the ligation mechanism of self-ligating brackets does not seem to affect duration of treatment.
