Effects of miniscrew orientation on implant stability and resistance to failure

Introduction The purpose of this study was to determine the effect of miniscrew implant orientation on the resistance to failure at the implant-bone interface. Methods Miniscrew implants (IMTEC, Ardmore, Okla) were placed in 9 human cadaver mandibles, oriented at either 90° or 45° to the bone surface, and tested to failure in pull-out (tensile) and shear tests. The line of applied force and the orientation of the implants aligned at 45° were either parallel or perpendicular to the maximum axis of bone stiffness. In the shear tests, the implants aligned at 45° were angled toward and opposing the axis of shear force. Results The implants aligned at 90° had the highest force at failure of all the groups (342 ± 80.9 N; P