Effectiveness of 3 methods of anchorage reinforcement for maximum anchorage in adolescents: A 3-arm multicenter randomized clinical trial

Abstract

The objective of this 3-arm parallel randomized clinical trial was to compare the effectiveness of temporary anchorage devices (TADs), Nance button palatal arches, and headgear for anchorage supplementation in the treatment of patients with malocclusions that required maximum anchorage. This trial was conducted between August 2008 and February 2013 in 2 orthodontic departments in the United Kingdom. The study included 78 patients (ages, 12-18 years; mean age, 14.2 years) who needed maximum anchorage. Eligibility criteria included no active caries, exemplary oral hygiene, and maximum anchorage required. The primary outcome was mesial molar movement during the period in which anchorage supplementation was required. The secondary outcomes were duration of anchorage reinforcement, number of treatment visits, number of casual and failed appointments, total treatment time, dento-occlusal change, and patients' perceptions of the method of anchorage supplementation. Treatment allocation was implemented by contacting via the Internet the randomization center at the University of Nottingham, Clinical Trials Unit. The randomization was based on a computer-generated pseudo-random code with random permuted blocks of randomly varying size. A research assistant who was blinded to the group allocation recorded all data. The patients were randomly allocated to receive anchorage supplementation with TADs, a Nance button on a palatal arch, or headgear. They were all treated with maxillary and mandibular preadjusted edgewise fixed appliances with 0.022-in slot prescription brackets. They were followed until orthodontic treatment was complete. Seventy-eight patients were randomized in a 1:1:1 ratio among the 3 groups. The baseline characteristics were similar in the groups, and they were treated for an average of 27.4 months (SD, 7.1 months); 71 completed orthodontic treatment. The data were analyzed on a per-protocol basis and showed no differences in the effectiveness of anchorage supplementation between TADs, Nance button palatal arches, and headgear. Compared with headgear, the average mesial movements of the maxillary right molar were 0.62 mm (-0.32 to 1.55 mm) with the Nance and -0.58 mm (-1.53 to 0.36 mm) with TADs; the maxillary left molar was moved -0.09 mm (-1.00 to 0.83 mm) with the Nance and -0.96 mm (-1.89 to -0.04 mm) with the TADs. Peer assessment rating scores were significantly better with the TADs than in the headgear and Nance groups. The patient questionnaires showed that comfort levels on placement of the TADs and the Nance were similar. Headgear was more troublesome and less popular with the patients. There was no difference in the effectiveness between the 3 groups in terms of anchorage support. There were more problems with the headgear and Nance buttons than with the TADs. The quality of treatment was better with TADs. As a result, TADS might be the preferred method for reinforcing orthodontic anchorage in patients who need maximum anchorage. ClinicalTrials.gov Identifier: NCT00995436. The protocol was published on the above site before the trial commencement. The British Orthodontic Society Foundation funded the study and American Orthodontics provided all the TADs and associated equipment.