Manipulating the Mandibular Distraction Site at Different Stages of Consolidation
Purpose
The purpose of this study was to define optimal timing and conditions for correcting an open bite side effect by manipulating the distraction site with orthodontic springs after mandibular distraction.
Materials and Methods
At 0, 1, 2, 3, and 8 weeks postdistraction, interarch springs were attached for 2 weeks to close distraction-produced open bites in 45 rabbits. Distractors were removed in half of the animals receiving spring treatment. Segment position was recorded by weekly direct measurements and radiographs. Tissue samples were collected at the end of spring application for microcomputerized tomography analysis and measurements of lateral symmetry.
Results
Orthodontic springs closed the open bite with or without distractors in place immediately after distraction and partially corrected the bite at later stages of bone consolidation. Distractor removal produced more rapid bite closure but also introduced lateral buckling of the distraction site during early consolidation. The lateral buckling was not observed if springs were applied after 2 weeks of consolidation. The amount of bite correction with orthodontic springs correlated with mineralization of the distraction site.
Conclusion
During the consolidation period, a distraction site can be callus manipulated with orthodontic springs to correct an open bite. The amount of correction depended on when springs were placed and whether distractors were removed at the time of spring application.
⁎Formerly, Visiting Scholar, Center for Craniofacial Molecular Biology, Childrens Hospital Los Angeles, Los Angeles, CA; and Currently, Chairman, Oral and Maxillofacial Surgery Department, Affiliated Medical College, Qingdao University, Shandong, China.
†Formerly, Research Associate, Department of Radiology, Childrens Hospital Los Angeles, Los Angeles, CA; and Currently, Assistant Professor, Department of Radiology, School of Medicine, University of California, San Diego, San Diego, CA.
‡Chairman, Department of Oral and Maxillofacial Surgery, University of Southern California, Los Angeles, CA.
§Formerly, Research Associate, Department of Radiology, Childrens Hospital Los Angeles, Los Angeles, CA.
¶Oral and Maxillofacial Surgery Resident, University of Southern California, Los Angeles, CA.
∥Orthodontic Resident, St Louis University, St Louis, MO.
#Director, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA.
⁎⁎Assistant Professor, Center for Craniofacial Molecular Biology, University of Southern California, Los Angeles, CA; and Director, Craniofacial Orthodontics, Childrens Hospital Los Angeles, Los Angeles, CA.
Address correspondence and reprint requests to Dr Yen: Center for Craniofacial Molecular Biology, University of Southern California School of Dentistry, CSA 103, 2250 Alcazar Street, Los Angeles, CA 90033
ABSTRACT