Intrusion of posterior teeth using miniplates: intrusive mechanics is not the same as intrusion force

Abstract

Objective: Biologically explain some of the bone mechanisms involved in the intrusion, or intrusive effect, of teeth submitted to skeletal open bite correction using four miniplates. Methods: The results of dental intrusion were measured and compared in 3D reconstructions of cone beam computed tomography scans taken before and after treatment of 20 patients with skeletal open bite, aged between 18 and 59 years. Results: The results allow deducing that the compression and traction forces biologically promoted deformation or deflection of the osteocyte network that controls bone design, and these effects involved the external and internal surfaces of the bone, with the formation of new layers, including the cervical portion of the alveolar bone crest. This helps understanding how dental intrusion occurs in intrusive mechanics, whose forces are of inclination rather than intrusion. The root resorptions caused by the use of miniplates were insignificant, due to the more homogeneous distribution of forces in the several teeth simultaneously involved. Conclusion: Imaging studies in CT scans tend to capture in details the subperiosteal and endosteal phenomena of dental intrusion - before and after the application of intrusive mechanics -, in the form of a set of modifications called dental intrusion or intrusive effect .

Craniomandibular transverse tomographic evaluation after anterior open bite orthodontic treatment with miniplates anchorage

“…The miniplates were placed buccally, away from the center of resistance. When intrusion forces were applied buccally, a tendency for buccal flaring was provoked, which was indeed the most common movement in the intrusive mechanics [ 23 ]. Despite this, in the present study, the change in the transverse dimension was independent of the amount of intrusion carried out.…”

What changes in the biology of bone movement induced with mini-implants/miniplates is the synchronicity

“…In the induced tooth-bone movement with enhanced anchorage, the applied force is distributed more uniformly across the bone and tooth structures, justifying why tooth resorptions are less frequent and intense in orthodontic treatments with miniplates than those observed in conventional treatments. [8][9][10][11][12]…”