Comparison of Active Tiebacks and NiTi Coil Springs Regarding En-masse Retraction in Bimaxillary Protrusion Patients

Background: Orthodontic forces generate comparable, opposite reactions on anchorage units, known as anchorage loss, potentially causing unwanted movements that adversely impact outcomes. Likewise, anteroposterior corrections might be complicated, and facial aesthetics can be compromised. This study attempted to compare anchorage loss when en-masse retraction was applied in patients with bimaxillary protrusion with active tiebacks and coil springs as two different methods. Methods: Sixteen Cl I bimaxillary protrusion patients were studied in two groups of active tiebacks and NiTi coil springs with random assignment. Changes in first molar positions and anchorage loss were quantified using lateral cephalograms before en-masse retraction and after space closure (T0 and T1, respectively). Paired t-test and independent t-test were used for statistical analyses. P-value<0.05 was considered as significant. Results: Molar anchorage loss was noted in both groups during en-masse retraction, with the active tieback group exhibiting less anchorage loss. An increase of 1.78 mm was noted in the mean distance between the pterygoid vertical (PTV) and the distal contact point of the upper first molar using active tiebacks; in contrast, the increase with coil springs was 3.37 mm, with no significant difference between these two groups (P=0.22). Conclusion: The two methods exhibited a statistically significant difference in anchorage loss, with coil springs causing greater anchorage loss; therefore, active tiebacks more effectively decreased anchorage loss during en-masse retraction.