Abstract
Objective
To compare mesial movement of upper first molars during maxillary canine retraction using a pre-adjusted edgewise appliance provided by anchorage reinforcement and a transpalatal arch or mini-screw implant.
Design
Randomized clinical trial.
Setting
Department of Orthodontics and Dentofacial Orthopedics, Armed Forces Medical College, Pune, India.
Subjects and methods
From a cohort of subjects requiring the extraction of both upper first premolars and pre-adjusted edgewise appliances to correct their malocclusion, a total of 30 were randomly allocated to receive two different forms of anchorage reinforcement: Group A – receiving mini-screw implant and Group B – receiving a transpalatal arch Group A subjects received titanium mini-screw implants placed at the start of treatment between the maxillary second premolar and maxillary first molar. Maxillary second premolars were secured to the mini-screw implants using of 0·010-inch stainless steel ligature wire. Group B subjects received a custom-made transpalatal arch which was soldered to maxillary first molar bands. Active canine retraction was initiated in both groups on placement of a 0·019×0·025-inch stainless steel archwire using nickel titanium closed coil springs.
Outcome measures
Mesial movement of the upper first molars as measured on pre- (T1) and post-treatment (T2) lateral skull radiographs.
Results
The results showed that in Group A the mean mesial movement of the first molars between T1 and T2 was 0·0 mm (SD 0·02; P = 0·90), whereas in Group B there was a mean forward movement of the first maolars of 2·48 mm (SD 0·71; P<0·001).
Conclusion
In this trial, mini-screw implants placed prior to levelling and aligning were able to provide absolute anchorage during maxillary canine retraction, in contrast to a transpalatal arch.
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