Treatment of Class III Cases with Temporary Anchorage Devices

There are many ways of using temporary anchorage devices (TADs) to treat patients with severe Class III malocclusions. The mini-plate is one example but a surgical flap is required to place and remove the device. Miniscrews placed in the retromolar pad enjoy the advantage of being placed in dense cortical place, but it is difficult to use them to apply direct force to retract the whole lower arch. The inter-radicular mini-screw is easy to place, but the amount of whole lower arch distalization is very limited. In this article, the author will discuss the use of miniscrews placed in the buccal shelf to correct severe Class III malocclusions. As long as the patient has an orthognathic, or at least acceptable profile, most severe Class III malocclusions can be treated by this method. Buccal shelf mini-screws are placed outside the alveolar process, so extensive lower arch distalization is possible. The thick cortical plate of high density bone in the buccal shelf area offers very good skeletal anchorage for retracting the mandibular arch and/or intruding lower molar to correct an anterior openbite. When treatment is complete, the miniscrews can be removed easily, even without local anesthetic. In this chapter, the anatomic considerations, materials and size of the screws, and the clinical application will be discussed and illustrated with case reports.

Keywords: Class III malocclusion, MEAW technique, buccal shelf, mini-screw, extra-alveolar TADs, biomechanics of Class III treatment, distalization, entire mandibular dentition, unilateral posterior crossbite, nonextraction approach, a 6 degrees-of -freedom jaw movement recording system, TMD, jaw function, MRI, coronal view, facial asymmetry.