Mass retraction movement of the anterior upper teeth using orthodontic mini-implants as anchorage.

BACKGROUND: Several studies have demonstrated the application of mini-implants in the orthodontic treatment as anchorage during the retraction movement of the anterior teeth.

PURPOSE: This study was designed to evaluate the mass retraction movement of the anterior upper teeth using orthodontic mini-implants as anchorage.

MATERIALS AND METHODS: Nine patients with class I malocclusion and Angle's class II, needing extractions of the upper first premolars, were enrolled in this case series. The retraction was performed using sliding mechanics and orthodontic anchorage on mini-implants. Measures were taken by initial and final cephalometric X-rays of the retraction movement to evaluate whether the mini-implants remained stationary and displacements of the incisors and the upper first premolars.

RESULTS: Out of 18 mini-implants, 8 mesialized (0.45 mm, average) and 3 extruded (0.14 mm, average). The upper incisors were retracted on the average of 4.21 mm, extruded 0.33 mm, and tipped 10.3°. There were no statistical significant modifications in the placement of the posterior teeth.

CONCLUSIONS: Although there was a very small displacement of the mini-implants, they still provided an adequate anchorage for the retraction of the anterior teeth, and there was no loss in the anchorage of the posterior teeth.