Variable axis implant placement guide for bone anchoring mini-screws.

Abstract

In the field of orthodontics, mini-implant anchorage (MIA) devices, such as mini-screws, have become an undeniable advancement in recent years. They offer a powerful anchorage method that allows for precise and predictable tooth movement. The use of MIAs reduces the difficulty and discomfort of placement and removal while providing highly resistant anchorage, superior to that of conventional MIAs. Despite standardized protocols, the placement of infrazygomatic mini-implant anchorage (IZC MIA) requires experienced surgical skill, demanding training and practice, and many practitioners are hesitant to use them despite their undeniable advantages. The placement of these mini-screws is complex, and its success hinges on extremely precise insertion combined with achieving comfortable emergence, consistent with the planning based on 3D radiographic images. The insertion is performed in two stages.First, slow screw insertion begins at 90° to the osteomucosal surface. A 1-2 mm intraosseous anchor is then established, followed by a gradual change of axis during screw insertion until the terminal axis of the MIA (Mini-Insertion Arborist) is reached. The depth of penetration allows for double cortical anchorage. Implant guides serve to orient the instruments and implants in three dimensions during placement. Their use would improve the safety of MIA IZC placement and could thus make this new technology accessible to a large majority of practitioners. The major difficulty in using guides for MIA IZC implantation lies in the need for extremely precise changes in the implantation axis of the mini-screw during slow screw insertion.The invention described in this document is characterized by the creation of an original guide allowing a change of axis during the mini-screw implantation operation and ensuring constrained positioning of the mini-screw during all phases defined by three-dimensional implant planning.