Application Of Different Distraction Osteogenesis In Mandibula Defect Restoration

Objective:Oral and Maxillofacial surgical distraction osteogenesis(DO) is now mainly applying in micro-mandibula abnormality caused by congenital growth of mandibula, and the distraction osteogenesis includes monofocal distraction bifocal distraction, trifocal distraction.It has only a little experimental research and clinical application in the restitution of a segmental defect of mandibula.Almost of the tools for distraction osteogenesis belong to outer-mouth style ones,which have fairly large difference on the aspects of the quality,design structure,and mode of fixing of the tools for distraction osteogenesis required by mandibula defect orthodontics.This test, according to international standard,designs out built-in bifocal distraction and trifocal distraction.Through establishing different bifocal distraction and trifocal distraction to conduct stretching to the goat mandibula defect,and observes and researches the osteogenetic process to compare with the new bone formation through two different methods.Methods:8 adult goats of 10-12 months old were randomly divided into bifocal Distraction group(n=4) and trifocal distraction group(n=4) which was self-designed according to International Distraction Group standard.Kill the two group goats 8 weeks after completion of distraction.Newly grown bone tissue sample at jaw distraction area has been analyzed by X-Ray and bone densitometry,and part of which was made into deliming paraffin section and HE colorations.Stiff tissue microsection scanning electron microscopy and Stiff tissue microsection tetracycline fluorescence paired labeled technique analysis is as well done to the sample.Bone densitometry analysis data is calculated by statistical software SPSS 11.0,and when P＜0.05 the discrepancy is of significance meaning.Results:All the 8 test goats can alive to the planned time without infection in the wound of the stretching area.All of which can take food in a good manner after operation, and their wounds could heal in Stage I and stitches could be taken out in 7 days.After execution,it can be observed that all the stretching tools are well fixed without any looseness;new bone is formed in the stretching clearance.In addition,it also can be seen that the new sclerotin in the stretching areas of the two test groups has no obvious difference.The results from X-way,histology,bone density test,ESEM,and double marking of tetracycline fluorescence indicate that there is no obvious difference between bifocal distraction and trifocal distraction,and the bone trabecula of the new bone in the stretching area is thick in the stretching area.Furthermore,it can be seen that mature Haversian system,lots of bone absorption lacuna and rather high density shadow,indicating new bone formation and calcification.However,its density is lower than the surrounding former bone tissue.It can be seen that a few of its center part is of penetration of light,and the bone cutting line around the transfer dish is getting blurring,and lots of bone trabecula of the new bone can been seen among the stretching clearance through an electronic microscope.The bone density is loose,and it also can be seen that in the central area the collagenous fibre and new bone osteosis making a line along the stretching direction.The border of the new bone and the original bone are of lots of fluorescent combination with the stretching area with a obvious border with the original surrounding tissue,which shows that active new bone has been formed with the stretching area,and the results of bone density test and analysis is of no statistical significance(p＜0.05). Conclusions:In the large area mandibula defect restoration,trifocal distraction bifocal distraction has no obvious differences with the bifocal one,but its stretching period is shorter the that of the bifocal one,which is able to provide a better stretching way for large bone defection restoration in clinical use for reducing stretching time.