title: Comparison of different distraction rates in the mandible: an experimental investigation.
abstract: This study evaluated bone distracted in rabbit mandibles at different intervals and with different daily rates of distraction histologically with the goal of attaining a universally accepted distraction protocol. Osteogenesis was investigated in mandibles distracted at different rates in 24 New Zealand rabbits using a custom-made submerged distractor. Distraction was started on the third postoperative day for a total of 10 mm. The animals were divided into four groups each containing six rabbits. Group 1 was distracted 0.5 mm twice a day; Group 2 was distracted 1.0 mm once a day; Group 3 was distracted 1.0 mm twice a day and Group 4 was distracted 2.0 mm once a day. All the animals were sacrificed 6 weeks after completion of distraction. Half of the distracted mandibles were decalcified for H&E staining and polarized light microscopy studies. Sections of the undecalcified half of the samples were stained with Goldner's stain. The results indicate that a distraction rate of 1.0 mm per day produced the best osteogenesis among the tested rates. There was no great difference in osteogenesis between 1.0 mm once a day and 0.5 mm twice a day. However, 0.5-mm distraction may result in immature bone healing. Distraction of 1.0 mm twice a day resulted in incomplete osteogenesis, while distraction of 2.0 mm once a day resulted in fibrous union. It is clear from these results that a shorter period of device fixation should be achieved by methods other than rapid distraction.
authors: Department of Maxillofacial Surgery & Diagnostic Sciences, King Saud University, Riyadh, Saudi Arabia.
authors: K A
authors: KA
authors: al Ruhaimi
mesh_terms: D000818:Animals; D002985:Clinical Protocols; D008334:Mandible / Q000473:pathology* / Q000601:surgery; D019186:Mandibular Advancement / Q000379:methods*; D019857:Osteogenesis, Distraction / Q000379:methods*; D011817:Rabbits; D013997:Time Factors; D016896:Treatment Outcome