Effects of mandibular distraction osteogenesis on the dental germ development and eruption

Objectives:To study the effect of mandibular distraction osteogenesis on the development and eruption of dental germ. Methods:12 adolescent dogs with the age of 4-6 months were random divided into two groups (6 in experimental group and 6 in control group). The internal distractors were inserted on the body of mandible after the corticotomy. After seven-day latent period, the mandibles were then distracted at a rate of 1mm per day for 7 days in the experimental group. Radiographic and histological changes around the tooth germ were observed on 0,1,2,4,6,8 weeks post distraction. Results:The mandible was prolonged for 7mm on both sides after distraction. All the dental germs were developed and erupted normally in 8 weeks after the distraction of mandible. The shape and length of the root was almost same as that of the control. The dental germs had the tendency to move to the area of the bone formation and erupt at the formed bone after distraction, while the congestion of dental pulp and the resorption of dentine were found at the same time. Conclusion:The dental germs can develop and erupt normally during the mandibular distraction. The distraction of maxilla and mandible is a good way on the treatment of the cases with dental crowding by increasing the length of dental arch. This research was supported by the Scientific Foundation of Shannxi province. 2001K10-G(2).