| Objective: Bony malocclusion early treatment that growth modificationtreatment has become one of the important contents in modern clinicalorthodontics. Because of the maxillary anteroposterior and verticalunderdevelopment, it manifests maxillary retrusion, midfacial sag and anteriorcrossbite patients.In the primary dentition, it was treated by occlusal pad withspring, but it only applied to the teeth not on bone remodeling; The functionand bone anterior crossbite needs traction and larger force of the jaws early.The front traction treatment on bone remodeling effectly, but because ofcomplicated device, it is not easy to receive by children. We place the microexpansion screw in the splint appliance, We want to know whether it can playan importment role in malocclusion.Methods: fifteen eight-week-old New Zealand white rabbits (bodyweight1.5-1.7kg) were randomly divided into the experimental group andthe control group, the experimental group8and the contrast group7. Theexperimental group New Zealand white rabbits wore Protrusive一typeappliances for two weeks, while the control group did not wear appliances. Inaddition to the rabbits in the experimental group were eating pap, all animalswere eating pellets. Artificial light, free, drinking water. The experiment lastedfor two weeks. The experimental rabbits at7th day and1st day before killedwere injected tetraeyeline25mg/Per kg in abdominal cavity (tetracycline wasprovided by Chinese Medical and Biological Production Institute). After twoweeks of expandtion,Taking the organization (including the incisor, maxillarypalatal plate and palatal), along the middle of maxillary divided into rightand left, Take the left side maxillary bone to prepare HE slices, counted thecells of the osteoblasts and the right side Observated by tetracyclinefluoreseence stain: The photograph was magnified40times by OLYMPUSAX80fluorescence microscope.we observate the tetracycline band of the maxillary palatal and measured the integral optical density by MetamorphImaging System V4.5image analysis software.The measurement data was fed into the SPSS13.0analysis software,calculated the mean value of each group: use the mean±standarddeviation(x±SD) to represent. Using the t test to compared analysis the variousindicators between the experimental group and control group(α=0.05).Results:1Histological observation:The experimental group HE staining show there are a lot of collagen fiberalong the direction of stress in the stretch zone, where in visible large spindleformation fiber cells, undifferentiated mesenchymal cells and oval osteoblastaggregation. The experimental group maxilla palatal marginal bone osteoblastis active, and a small amount of osteoid appeared belowed the osteoblasts.While it appears of osteoblasts in some regional, it is less than the osteoblasts,so new bone appears, new bone trabecular alignment along the stress direction;There are varying amounts of osteoblasts in the control group of the maxillapalatal and the activity of the osteoblast is weak, occasionally osteoclasts.Statistical analysis show that: the experimental group and the control groupwere significantly different(P <0.05).2Observations by tetracycline fluorescence stain:The experimental group showed fluorescence broad bands along thestretch direction obviously in the osteoid. in some regions, a number offluorescent bands was parallel because osteoblastic activity was active in theexpansion process. At the same time, While in the control group, we can see alittle of fluorescence bands. Statistical analysis showed that: the experimentalgroup and the control group were significantly different(P <0.05).Conculusion:1It was successful in establishing the model of New Zealand rabbit maxillarysagittal maxillary expansion appliance.2The growth of New Zealand rabbit maxillary sagittal maxillary expansioncan cause palatal sagittal orientation of the bone remodeling and growth. |
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