Biomechanical anchorage evaluation of mini-implants treated with sandblasting and acid etching in orthodontics.

PURPOSE: The purpose of this study was to assess the stability of sandblasted and acid-etched miniscrew implants based on orthodontic mechanics for space closure after tooth extraction.

MATERIALS AND METHODS: Twenty-four orthodontic mini-implants were placed in 13 patients, for a skeletal anchorage purpose, all prepared by the manufacturer (3M Unitek-IMTEC Ortho USA) with sandblasting and acid treatment. Anchorage measurements were made on occlusal radiographs, on a monthly basis in a 6-month period.

RESULTS: All the mini-implants were effective for the clinical trial; but 65% of the mini-implants, after been loaded, showed up to 1 degree, or less, of displacement, while 35% showed ≥2 degrees shift. The mandible mini-implants resulted in a smaller amount of displacement than the ones located in the maxilla. The ones located at the anterior maxilla displaced less than the posterior. The best results were obtained with the 8-mm mini-implants, followed by the 6-mm and 10-mm mini-implants.

CONCLUSIONS: Modifying the mini-implant surface with sandblasting and acid treatment offers good bone anchoring for orthodontic purposes.