PASS versus MBT™ for evaluation of anchorage control in three-dimensional measurements: a randomized controlled trial

Abstract

Summary Background Growth and development might lead to anchorage loss during orthodontic treatment, such as the mesial drift of molars, the compensation characteristics of upper molars following mandibular growth, or the angulation of molars before treatment. Different anchorage reinforcement devices have been developed to prevent mechanical anchorage loss, but the anchorage loss resulting from physiological factors should also be taken into account. Objective To explore the efficacy of a new strategy to control physiologic anchorage compared with that of the conventional straight-wire appliance. Trial design Randomized controlled trial (RCT). Methods Participants of Han ethnicity were randomized into the physiologic anchorage spee-wire system (PASS) group or McLaughlin–Bennett–Trevisi (MBT™) straight-wire group by minimization random allocation. The eligibility criteria were patients with a Class I or II molar relationship, permanent dentition (11–35 years old), fixed appliances involving the extraction of at least two upper first premolars, and medium or maximum anchorage requirements. Pre-treatment and post-treatment dental casts were scanned into digital casts and measured using a blinded method. Mesial displacements of the upper first molars were considered as the primary outcome for evaluating anchorage control. Measurements were taken for subgroups based on age. Results Data from 60 participants were analysed. The baseline characteristics were not significantly different between groups. Mesial displacement of the upper first molar (in mm) was 2.96 ± 1.52 in the PASS group and 2.70 ± 1.66 in the MBT group (P = 0.521). The variation in incisor torque was −6.94 ± 6.35 degree in the PASS group and −11.76 ± 7.65 degree in the MBT group (P = 0. 010). The incisor retraction (in mm) was 4.24 ± 1.99 and 5.67 ± 2.27 in the PASS and MBT groups, respectively (P = 0.012). Adverse effects were not documented in any patient. Limitation The study was a single-centre study. Conclusions Compared with the MBT group, the PASS group without additional anchorage devices could attain well anchorage control by considering the dentoalveolar compensation of anchor teeth. Registration This RCT was registered at the Chinese Clinical Trial Registry (Chictr.org.cn) ChiCTR-TRC-13003260.

Methods for Anterior Torque Control during Retraction: A Systematic Review

“…The average group size was 20 patients. The largest groups were found in articles by Chen et al 2 and Xu et al 3 -32 individuals per group. The smallest groups were included in Deepak et al's 4 study -10 subjects per group.…”

“…Although blinding of participants was impossible, the overall risk of bias was reduced in some studies by blinding of assessors during the outcome analysis. In the articles by Al-Sibaie et al 11 , Al-Imam et al 14 , Chen et al 2 and Tunçer et al 12 , the assessor was not directly involved in the study and did not know its purpose; hence, the risk of bias was considered low. In the article by Sadeka et al 5 , the assessor could easily de ne the purpose of the study (patients treated with labial or lingual appliances); thus, blinding was not possible, and the risk was considered high.…”

“…In Davoody et al 10 and Chen et al 2 articles, the authors stressed the possibility of attrition bias. In the rst study, the loss of participants was approximately 30%, and in the second study, it was approximately 6%.…”

“…In the rst study, the loss of participants was approximately 30%, and in the second study, it was approximately 6%. Hence, the risk of selective reporting in Davoody et al 10 article was de ned as high, while in Chen et al 2 article, it was de ned as moderate. In that category, the article by Tunçer et al 12 was also of moderate risk.…”

“…Control of the anterior roots torque is a very important issue in orthodontic treatment. It allows stability of the normal interincisal angle, which in turn helps to support soft tissues thus securing a harmonious facial pro le [1][2] . The discussed torque is also substantial for maintaining a healthy periodontium, which minimizes the risk of the tooth migration, recession, fenestration, or dehiscence in the front area of the dental arch 1 .…”