Experimental study on the bone quality of the new bone after mandibular distraction osteogenesis

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 13672075
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Surgical dentistry
• Research Institution: Asahikawa Medical College
• Principal Investigator: MATSUDA Mitsuyoshi Asahikawa Medical College, Associated Professor, 医学部, 助教授 (30173850)
• Co-Investigator(Kenkyū-buntansha): FUJIMORI Masaki Asahikawa Medical College, Instructor, 医学部, 助手 (70343019) ; TAKEKAWA Masanori Asahikawa Medical College, Assistant Professor, 医学部, 講師 (50216876)
• Project Period (FY): 2001 – 2002
• Keywords: Distraction osteogenesis / Computed tomography / Osteodensitometry / Scanning electron microscopy / Bone intensity / Bone density

Research Abstract

Purpose: The purpose is this study to examine the maturation degree of the newly formed bone after distraction osteogenesis. Materials and Methods: Distraction devices were placed in the mandible of rabbits (6-months-old, male, weighed 3 kg). The protocol included of 4-day latency and distraction rates of 0.9 mm/day for a 7.2 mm gap. The wounds were examined after 7, 10, 14, 21, 28 and 56 days of neutral fixation. The bone quality of the new bone was assessed to change CT value into CaCO_3 equivalent, using computed tomography-assisted osteodensitometry (calibration phantom B-MAS). The bone intensity of the distracted area was examined by a load test. The morphology was examined by scanning electron microscope (SEM). As a control, the same area of the opposite side were used. Results: The bone quality showed a tendency to increase with the extension of fixation period. The peak was in 28 days of fixation. The quality of buccal side was low as compared with the lingual side. In the central area of the gap, the quality was gradually increased and showed higher value than control. After 28 days, the quality was decreased. In SEM, the new bone was seen at the distraction area at 7 days of fixation. 28 days of fixation, the new bone in the distraction area matured and Howship's lacunae were seen on the bone surface. The peak of the intensity of the distracted bone was seen in 28 days of fixation. Conclusion: 1. The assessment of the bone quality using computed tomography-assisted osteodensitometry is useful for the judgment of the maturation of callus after the distraction and for the decision of the proper occasion of removal of the distraction device. 2. The newly formed bone in the distraction gap was matured morphologically at the 28 days of fixation but the value of the bone quality was low as compared with control. 3. We think the study should go on for more long term.