Effects of distraction forces and frequency of distraction on bony regeneration.

The rate and frequency of distraction have a decisive influence on the regenerative process. We tested a newly developed hydraulic osteodistractor in 12 pigs, which were assigned to have continuous and intermittent osteodistraction of the mandible after osteotomy. The forces necessary to distract the mandible were recorded during intermittent distraction. These data were then used for continuous distraction of the bone. Continuous osteodistraction resulted in intramembranous regeneration of bone, whereas intermittent osteodistraction caused chondroid ossification in the regeneration of the bone. Continuous osteodistraction caused speedier regeneration, and distraction forces were lower than with intermittent distraction.