Friction or Frictionless: What is the Most Effective Method for Retracting Anterior Teeth?

To evaluate the effectiveness of the friction-based (sliding mechanism with elastomeric chains) and frictionless (T-loop) methods for retracting anterior teeth in Angle Class I malocclusion.

This clinical intervention study examined the duration of maxillary incisor retraction from August 2022 to August 2024 in 42 adult patients who had completed canine retraction. The process involved resolving horizontal and vertical discrepancies, establishing a Class I relationship between the canines, and altering the overbite (the interproximal space between the lateral incisors and canines) until an ideal overbite index of 2 mm was achieved. Cone beam computed tomography (CBCT) was conducted before and after retraction to evaluate alveolar changes and speed.

The maxillary central incisors advanced 1.2 mm more in the sliding mechanism cohort than in the loop mechanism cohort (0.18 mm) (p < 0.001). The angle between the central incisor axis and the palatal plane decreased by 12.57° with sliding mechanics, which was significantly greater than the 9.65° decrease observed with the loop mechanism (p = 0.014). After retraction, the location of maxillary tooth roots changed, with the length of incisor roots decreasing by 1 mm and 0.81 mm in the central incisors and 0.67 mm and 0.61 mm in the lateral incisors, respectively (p > 0,05).

Following treatment, frictionless (T-loop) procedures generally provided superior control over the torque and extrusion of the incisors during retraction and were more efficient. However, root resorption rates were comparable between the frictionless and friction (sliding mechanism with elastomeric chains) groups.