Distraction osteogenesis for bony repair of cleft palate by using persistent elastic force: Experimental study in dogs

Objective: The purpose of this study was to investigate the possibility of closing a cleft and lengthening the hard palate by the technique of distraction osteogenesis with elastic forces and to evaluate the influence of the management on the facial structure. Design: Thirty 6-month-old mongrel dogs were assigned randomly to two groups with five subgroups for different purpose. Interventions: An 8- x 25-mm cleft was surgically created in the posterior hard palate in experimental and sham control dogs. Bone markers were implanted in the hard palate. Osteotomies were carried out followed by the installation of a distractor made of NiTi-shape memory alloy. Outcome measures: The results were evaluated clinically, radiographically, and histologically. Anthropometric data that represented the length, width, and height of the maxilla were taken on the dry skull of the control and experimental dogs and were analyzed statistically. Results: The cleft was closed and the hard palate was lengthened after 2 to 3 weeks of distraction in all the experimental dogs. New bone formation was found at the site of osteotomy. The variables of facial length, height, and width showed no significant difference between the two groups (p >.05). The length of the hard palate in the experimental group was longer than that in the control group (p <.01). Conclusion: Distraction osteogenesis with the elastic device of NiTi-shape memory alloy is effective for closing the cleft and lengthening the hard palate in a canine cleft model. There is no interference on the growth of the maxillofacial structures with the technique.