Mini-screw implant or transpalatal arch-mediated anchorage reinforcement during canine retraction: A randomized clinical trial

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.

Keywords:

• Mini-screw implant
• transpalatal arch
• anchorage loss
• canine retraction
• randomized clinical trial

Acknowledgments

The authors thank Dr Dinesh Chander Chaudhary for helping with the tracings for cephalometric analysis and Mr Varun Arora for providing all the statistical support for this study.