Osteodistraction of mandibles with a small bone defect at the planned osteotomy site: a histological pilot study in dogs.

AIM

To develop a treatment plan for cases in which a bone defect is located on the osteotomy line of mandibular osteodistraction (DO).

SUBJECTS AND METHODS

Bilateral DO was performed in 17 Mongrel dogs. Prior to surgery, the 34 hemi-mandibles were randomly allocated to three groups: C (n = 10; a standard DO was performed), D - G (n = 12; a bone defect was created on the DO osteotomy line), and D + G (n = 12; the bone defect on the osteotomy line was grafted). After one week of latency, 8 days of distraction, and 4 weeks of consolidation the animals were sacrificed, and the newly formed bone were examined.

RESULTS

In group C, two zones of immature trabecular bone originating from host bone margins were separated by a central fibrous zone. In group D + G uniform new bone formation of the entire distraction gap was observed. In group D - G the distraction gap was mainly filled with fibrous tissue. The values for the newly formed bone volume and trabecular thickness were not significantly different between groups D + G and C, but were higher than values in group D - G (p < 0.05).

CONCLUSION

When a mandibular defect is located at the site of distraction osteotomy, DO can be performed simultaneous with bone grafting of the defect.