Anchorage loss and inclination during retraction: A systematic review

This review focused on anchorage lost and incisor inclination variation in the orthodontic retraction process. It compared the effectiveness of skeletal anchorage to that of conventional anchorage. It also sought to clarify how extraction and retraction mechanics and bracket type affect anchorage control and torque expression. The PRISMA 2020 guidelines were used in this review. A comprehensive literature search of the PubMed, Scopus, ScienceDirect, and EBSCOhost databases was performed to identify studies published between January 1992 and 2025. Prospective clinical trials, cohort studies, finite element analyses and case reports of orthodontic retraction with or without extractions were included. Data for anchorage control and incisor inclination were obtained, and qualitative analysis was performed. We evaluated risk of bias with Cochrane RoB 2 tool. Thirty-five studies fulfilled the criteria for inclusion. The majority of studies demonstrated that skeletal anchorage systems, such as mini-screws and miniplates, enable superior retention of anchorage and torque control compared to traditional techniques. Mass retraction was superior, faster method than two-step canine retraction especially with the use of skeletal anchorage. The mechanics, biomechanical system used and type of force were the major factors in determining anchor loss and angle change. The differences between MBT and self-ligating brackets were small, whereas clear aligners had mild to moderate control with the use of skeletal anchorage but generally decreasing trends. Traditional anchorage devices often result in loss of anchorage, which affect anterior retraction and torque control. Especially, the stability and biomechanical efficiency of skeletal anchorage devices, such as mini-screws are superior when retraction is performed en masse (EMR). Extraction protocol and force system are important for torque control as well as anchorage. The bracket type hardly matters with respect to anchorage reinforcement, and clear aligners have low torque control capabilities. Better-designed studies are necessary to establish evidence-based standardized parameters for anchorage and torque control.