Comparative Evaluation of Root Resorption in First Upper Premolars Treated with Active and Passive Self-ligating Brackets: A Prospective Split-mouth Study

Introduction This prospective observational split-mouth study aimed to compare the effect of self-ligating bracket type (active versus passive) on the extent of Orthodontically Induced Inflammatory Root Resorption (OIIRR) in maxillary first premolars during alignment, leveling, and initial torque expression in orthodontic treatment. Materials and Methods A split-mouth design was employed in 10 patients (7 females, 3 males; 20 maxillary first premolars). Each patient received simultaneous orthodontic treatment with active and passive self-ligating brackets. The right side was randomly assigned to active self-ligating brackets (Forestadent, Pforzheim, Germany), and the contralateral side to passive self-ligating brackets of the same manufacturer. After nine months, both premolars were extracted and analyzed using a 3D Confocal Laser Scanning Microscope (Lext OLS 4000, Olympus Corporation). Volumetric measurements of resorption craters (area, volume, and depth) were obtained with specialized software. Results No statistically significant differences were observed in the extent of external root resorption between active and passive self-ligating brackets. Both bracket systems showed comparable mean values for resorption area, volume, and depth. Discussion This study provides the first direct intra-patient comparison of active versus passive self-ligating brackets, eliminating inter-individual variability. Findings suggest that the biological response leading to OIIRR is comparable between both bracket systems, indicating that individual biological susceptibility may outweigh the mechanical differences in bracket clip design during the initial stages of treatment. Conclusion Passive and active self-ligating brackets produce comparable levels of orthodontically induced inflammatory root resorption during early stages of treatment. Orthodontic forces should be maintained at the lowest biologically acceptable levels to minimize iatrogenic effects.