Efficacy of Novel PRP Loop versus Opus Loop for Anterior En-Masse Retraction in Angle’s Class I Dewey’s Type 2 Malocclusion: A Randomised Clinical Trial Protocol

Abstract

Introduction: Optimal space closure is a pivotal aspect of orthodontic treatment, particularly challenging in patients with bimaxillary protrusions and Angle’s class II division 1 malocclusion. Two primary methods, friction, and frictionless mechanisms, are employed for anterior teeth retraction. However, concerns over prolonged treatment duration and increased anchorage demands have prompted exploration into non-frictional approaches. Biomechanical properties significantly influence the efficacy of retraction loops, with ideal loops exhibiting high Moment-to-Force (M/F) ratios and low Force-to-Deflection (F/D) ratios. The “PRP loop” was developed inspired by existing designs, showing promising biomechanical characteristics in a finite element study. However, its clinical efficacy remains unexplored. Need of the study: More research is required to assess the clinical efficacy of the recently created PRP loop in promoting retraction. This trial attempts to evaluate the effectiveness of the PRP loop compared to current techniques, focusing on attaining effective anterior en-masse retraction. Through an analysis of the benefits and limitations of both methods, the research aims to shed light on which loop provides the best space closure. Aim: This study aims to evaluate and compare the PRP loop with the Opus loop for anterior en-masse retraction in Angle’s class I Dewey’s Type 2 malocclusion. Materials and Methods: A prospective single-blinded randomised clinical trial will be conducted in the Department of Orthodontics and Dentofacial Orthopedics at Sharad Pawar Dental College and Hospital, Sawangi, Wardha, Maharastra from September 2024 to April 2026. Thirty patients between the age of 15-30 years having Angle’s Class I Dewey’s type 2 malocclusion requiring maxillary premolar extraction will be included and divided into two groups (PRP and Opus loop groups) with the exclusion of Angle’s Class II and III cases. Treatment procedures include initial alignment, maxillary premolar extractions, and retraction using respective loops. Evaluation criteria encompass retraction rate, efficacy, and anchorage loss measured through study models and radiographic assessments. Statistical analysis will employ Student’s paired and unpaired t-test and Chi-square test with GraphPad Prism 7.0 and SPSS 27.0 software and a significance level of p<0.05.

Keywords

• anchorage loss
• frictionless mechanism
• retraction loops