Horizontal Pull-Out Strength of Orthodontic Infrazygomatic Mini-Implant: An In Vitro Study

Purpose: New modified mini-implants have recently come into use for reinforcing skeletal anchorage in orthodontic application. The aim of this study was to investigate the influence of the design of a mini-implant on its mechanical strength. Materials and Methods: We measured the insertion torques and horizontal pull-out strengths of 3 brands of infrazygomatic mini-implants (AbsoAnchor, Bioray, and Lomas; 2 mm for all). Five implants of each brand were manually driven 6 mm into the artificial bone. Significant differences in various parameters among the brands were investigated with the Kruskal-Wallis test. Results: There was no significant relationship between insertion torque and horizontal pull-out strength. The Bioray mini-implants had significantly greater horizontal pull-out strength than the AbsoAnchor mini-implants. Conclusions: The design of the mini-implant can influence its insertion torque and horizontal pull-out strength. In our findings, the horizontal pull-out strength of all mini-implants placed in the infrazygomatic crest was significantly greater than the orthodontic force applied. (Implant Dent 2011; 20:139-145)