This study was undertaken to test the hypothesis that a corticotomised tooth moves as a tooth-bone unit when under orthodontic force. A non-human primate model was designed to test the hypothesis. The non-human primate selected was Macaca fasicularis. Three adult males with erupted third molars were chosen so that extrapolation could be made to the adult human. The methods employed included the following: 1) Each animal had one treatment quadrant and one control quadrant per arch; 2) Pre-op and post-op study models were made; 3) All 2nd premolars, 2nd molars, and 3rd molars were banded; 4) A full-thickness flap procedure was performed at each quadrant; 5) The 2nd premolars were corticotomised in each treatment quadrant; 6) Retraction appliances were placed at all quadrants (two animals at 454 grams force, one at 227 grams force); 7) All first molars were extracted; 8) Radiopaque pins were implanted at treatment quadrants for radiographic evaluation of possible movement of the cortical plates in those quadrants; 9) Bone labels: Achromycin, Terramycin, and procyn dye were injected at the 2nd, 4th, and 6th week post-op, respectively; 10) Weekly quadrant radiographs were taken using a custom designed x-ray tube positioning jig; 11) All animals were sacrificed at 8 weeks post-op. There was no radiographic or bone label evidence of movement of the cortical plates at the corticotomy quadrants of any of the three animals in the study. The study models indicated a 26% greater movement of the mandibular corticotomised second premolars than the mandibular controls second premolars. There was 60% greater anchorage loss in the maxillary corticotomy quadrant than in the mandibular corticotomy quadrants. It was shown that the "heavy force," i.e., 454 grams, gave more movement in corticotomised retraction in the maxillary arch than did the "light force" of 227 grams.
The author's opinion is that the corticotomy procedure was efficacious, not due to a mechanical movement of a tooth-bone assembly, but due to a facilitation of physiologic tooth movement. Because the mechanism at the cellular level is potentially very complex and involves the immune system, this area requires further study.
Master of Science (MS)
Year Degree Awarded
Date (Title Page)
Library of Congress/MESH Subject Headings
Orthodontics; Corrective Malocclusion -- therapy Surgery; Oral
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This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.
Rynearson, R. David, "A Non-Human Primate Model for Studying Corticotomy-Facilitated Orthodontic Tooth Movement" (1987). Loma Linda University Electronic Theses, Dissertations & Projects. 1839.
Loma Linda University Electronic Theses and Dissertations
Loma Linda University. Del E. Webb Memorial Library. University Archives