Evaluation of the Rate of Anterior Segment Retraction Using Two Types of Mechanics

Evaluation of the Rate of Anterior Segment Retraction Using Friction Versus Frictionless Mechanics: A Randomized Clinical Trial

The rate of anterior segment retraction in bi-maxillary protrusion cases was evaluated comparing the friction and friction-less mechanics. since, there has been a lack of clear cut guidelines for clinicians for the optimum method for retraction, this randomized clinical trial was done.

Thirty bi-maxillary protrusion female patients were randomly allocated into either intervention groups. In the Friction group, retraction was accomplished using elastomeric power chains extending from crimpable hooks distal to the lateral incisors, on 0.017x0.025-inch Stainless Steel wires, to the mini-screws . While in the friction-less group with retraction done using T- loop springs made of 0.017x0.025-inch titanium molybdenum wires. Retraction force was set to 160g per side in both intervention groups. Activation was done every four weeks. Rate of anterior segment retraction was evaluated via digital models.

Inclusion Criteria:

• Female Subjects.
• Age 13-25 y of age.
• Skeletal Angle Class I malocclusion with Bimaxillary dentoalveolar protrusion in need of four 1st premolar extractions with maximum anchorage.
• Fully erupted permanent dentition without crowding.
• Good oral and general health.

Exclusion Criteria:

• Systemic Diseases or syndromes or on anti-inflammatory medication.
• Extracted or missing permanent teeth.
• History of previous Orthodontic Treatment.
• Parafunctional Habits.
• Badly decayed teeth.