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Abstract
Distraction osteogenesis is a surgical process involving gradual, controlled displacement of surgically created fractures which results in simultaneous expansion of soft tissue and bone. Unique feature of distraction technique is that bone regeneration by distraction osteogenesis is accompanied by simultaneous expansion of soft tissue matrix as an adaptive change to the tension generated by distraction forces. This technique was first described by Ilizarov who developed it experimentally and perfected it clinically. It was first used mainly to lengthen long bones. The reliability of this method has been examined by several authors who introduced this therapeutic principle to craniofacial surgery both experimentally and clinically so as to displace portion of the facial skull or the jaws. Also demonstrated the suitability of callus distraction for vertical augmentation of atrophic portions of the jaws in pre-prosthetic surgery. It is widely believed that new bone formation, occurs more or less in same way as intermembraneous ossification. Stretching of soft tissue is possible by distraction osteogenesis without any problems at a distraction rate of one millimeter per day.
The distraction technique involves creating an osteotomy in an area adjacent to an area of bone deficiency. Applying slow tension forces separates the bony edges, which creates a regenerate chamber from which the new bone and soft tissues are formed. Distraction osteogenesis (DOG), the gradual formation of new bone by progressive lengthening, has widely been applied in the orofacial region to overcome the drawbacks of so-called one-step orthognathic surgery such as Le Fort I osteotomy. Recently, this technique has been widely used in the mid-face region in subjects with cleft lip and palate who exhibit a retruded maxilla.