Distracted mandible does not reach the same strength as normal mandible in rabbits.

OBJECTIVE

The aim of this study was to determine the resistance and fracture strength values of the bone with the use of biomechanical tests in different consolidation periods of mandibular distraction osteogenesis.

STUDY

DESIGN

In this study, 21 mature male New Zeland rabbits were used. After distraction, rabbits were separated into 3 groups to experience 4, 8, and 12 weeks' consolidation periods. Nonoperated hemimandibles of 6 rabbits were used as a control group. After 5 days' latency period, 0.5-mm distraction was applied twice a day, i.e., 1 mm/d lengthening. After the 5-mm lengthening application, we left the animals for 1, 2, or 3 months of consolidation period. Bending stress and strength values of the bone at fracture point were measured with the use of a 3-point bending test.

RESULTS

There were significant differences between the control and 3 study groups regarding bending stress and strength values. In addition, each study group was significantly different from each other.

CONCLUSIONS

Bending stress and fracture strength of the bone may not reach that of normal bone after completion of 3 months' consolidation. It should be considered to keep in place extraoral appliances or comfortable intraoral distractors for a long period.