Bone analysis of distraction osteogenesis and autogenous onlay graft for placement of dental implant in a canine model

Bone analysis of distraction osteogenesis and autogenous onlay graft for placement of dental implant in a canine model
August 2004
Waheed Mohamed, BS
N.E. Hodges
L.A. Opperman
P.F. Franco
Journal of Oral and Maxillofacial Surgery Online
Statement of the Problem: Multiple reconstruction procedures have been described to improve alveolar bone in patients with defects associated with trauma, facial deformities, cancer, and premature dental loss. Alveolar distraction osteogenesis and bone graft augmentation have been described to improve these defects and to generate adequate bone support for placement of dental implants and future restoration. During this reparative phase, osteoclasts and osteoblasts play a major role throughout the healing process and can be used as an indicator of bone remodeling.
Objective: To evaluate osteoclastic and osteoblastic activity in distracted bone vs. bone grafted and the bone stability within osseointegrated implants in a canine model.
Materials and Methods: Five male adult canines underwent surgical dental extractions (mandibular premolars, second and third molars) and radical alveoloplasty. A square bone defect in the premolar area was created bilaterally. The first molars were retained to maintain alveolar height. Second and third molar healed area was used as a control site. The healing process was achieved during 8 weeks. Vertical alveolar distraction osteogenesis was performed using a custom made device in the left mandibular side with an activation rate of 0.5 mm twice a day for 10 days. In the contralateral site, iliac crest bone onlay graft was placed and stabilized with titanium screws. After a period of 12 weeks, distraction devices were removed from the left side and four SLA ITI-Straumann implants were placed in the distracted bone and left in situ for three months. The same procedure was performed on the grafted site, replacing the bone screws with dental implants. Grafted and distracted areas were then harvested, fixed, and decalcified prior to embedding and cutting 6¨µm sections. Tartrate resistant acid phosphatase staining was used to identify osteoclasts and AttwoodÇƒÙs staining was used to isolate osteoblasts.
Method of Data Analysis: The stained sections were digitized at ?Û5 magnification and imported to Metamorph Software where linear distances of total bone surface and surfaces covered with osteoblasts/osteoid were measured. The numbers of osteoclasts were counted along the measured bone to determine osteoclasts/¨µm.
Results: The osteoclastic values of control, distraction osteogenesis, and onlay grafts were 0.725 ¨± 0.08, 0.94 ¨± 0.07, and 0.60 ¨± 0.06 osteoclasts/¨µm respectively. The osteoblastic surface values for control, distraction osteogenesis, and onlay grafts were 0.09 ¨± 0.007, 0.12 ¨± 0.007, and 0.08 ¨± 0.007 osteoblasts/¨µm, respectively. Using ANOVA test, both results show a significant difference in distraction osteogenesis compared to the control and onlay grafted bone. The onlay site did not show a significant difference from controls, but the distraction group showed significantly more osteoclasts/¨µm than controls (P < .035) and the onlay group (P < .001). The distraction group also showed significantly more osteoblasts/¨µm than the controls (P < .0004) and the onlay group (P < .0001).
Conclusion: Distracted bone shows a significantly greater surface area of bone covered with osteoblasts and osteoclasts than control or onlay bone. This suggests high bone turnover in the distraction group indicative of healthy, active bone formation and activity, compared to the onlay bone.
References
Block MS, Almerico B, Crawford C, et al: Bone response to functioning implants in dog mandibular alveolar ridges augmented with distraction osteogenesis. Int J Oral Maxillofac Implants 13:342, 1998
Nomura S, Takano T: Molecular events caused by mechanical stress in bone. Matrix Biol 19:91, 2000
Publishing and Reprint Information
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Copyright ¨© 2004 by Elsevier Inc.
doi: 10.1016/j.joms.2004.05.131