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.
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.