Mini-Implant Screws for Bone-Borne Anchorage: A Biomechanical In Vitro Study Comparing Three Diameters.

Purpose: To evaluate the maximum strength and the maximum aperture supported by mini-implant screws of three different diameters in an in vitro rapid maxillary expander model.

Materials And Methods: Fifteen appliances were mounted in artificial bone polyurethane blocks. In each appliance, a Hyrax expander anchored by four mini-implant screw sets of three different diameters were divided into: group 1 (n = 5), 1.