Comparison of Maxillary First Molar Anchorage Loss Following Rapid Canine Retraction Using Periodontal Ligament Distraction Versus Dentoalveolar Distraction: A Randomized Split-Mouth Clinical Trail

Objective: To compare Periodontal Ligament Distraction (PD) and Dentoalveolar Distraction (DAD) with respect to maxillary first molars anchorage loss during rapid canine retraction. Materials and Methods: This randomized split-mouth clinical trial included 15 patients (mean age: 18.4 years) who required bilateral maxillary first premolar extractions and maximum anchorage during canines’ retraction. Each patient randomly received PD on one side and DAD on the contralateral side. Custom-made palatal distractors were activated at a rate of 0.6 mm/day. Anchorage loss was assessed by measuring the mesial movement and rotation of the maxillary first molars on study models before and after canine retraction. Statistical analysis was performed using paired t-tests (p<0.05). Results: Both techniques were associated with anchorage loss: however, the magnitude of anchorage loss was significantly greater in the PD group than in the DAD group. The mean mesial movement was 1.2 mm for PD vs. 0.6 mm for DAD (p<0.05). Mean molar rotation was 3.30° for PD vs. 2.10° for DAD (p=0.017). Conclusions: While both PD and DAD facilitate rapid canine retraction, the DAD technique demonstrated significantly better anchorage preservation for the maxillary first molars, resulting in less mesial movement and rotation. The choice of technique should consider the trade-off between anchorage control and the more invasive nature of the DAD procedure.