| Objective:During the regeneration surgeries of periodontology, Concentrate Growth Factors (CGF) is widely applied as a new type of regenerating material. Its advantages are minor post-surgery reactions, quicker healing reactions, impressive cooperation with the bone or bone-substitute on the enhancement of tissue regeneration and high biocompatibility. Early stage healing tissues (ESHTs) in the tooth extraction socket is the compound of osteoblasts, cytokines, vessels and fibrous connective tissues. Since it comes from the patient and contains high capability of tissue regeneration, the healing tissues in the extraction sockets is a good choice of small-scale regenerating material. It’s a new type of autogenous bone grafts(ABGs). In the study, by using a surgical periodontal tissue defect model, we would like to explore the effect of CGF on periodontal tissue regeneration and to figure out the better method for periodontal tissue regeneration..Methods:6 Beagle dogs (3 male and 3 female) were extracted of upper 3 premolars on both sides in surgery I. Two weeks later, we did the flap surgery on both sides of mandibular bone, covering second premolar to first molar. When the alveolar bone was exposed, we made a "U" shaped defect of 6mm × 6mm × 2mm sized on buccal side of the mesial root. The alveolar bone, periodontal ligament and cementum were all completely removed in the defect area, and a notch is made corronally and apically on the root surface respectively. There were 4 groups, named as A, B, C and D according to the different treatments. Group A, namely the control group, the defect was only filled with blood clot; Group B, the defect was filled with CGF; In group C, the defect received the CGF+Bio-Oss compound; while in Group D, the defect was filled with CGF+ ESHT taken out from the malxillary tooth socket. All animals were executed 12 weeks after surgery.Tooth blocks contained the defect tissue were decalcified, embedded in paraffin,serially sectioned and stained with hematoxylin eosin. Paraffin sections were performed for histological observation and histometric analysis were performed under microscope..Results:Histological observation disclosed that each defect were healed with similar structure. Newly formed bone extended apically from the bottom of apical notch. Along the root surface was the newly formed cementum which was characteristic of avascular and a thin layer of calcified connective tissue. There was always a space between the root surface and the newly formed cementum. Connective tissue between newly formed bone and cementum was composed of fibroblsts, blood vessels and fibers. Beyond the newly formed bone, a well organized connective tissue were formed and covered with epithelial cells in its outer surface.In CGF group, vessels and fibrin were more mature, trabecula arranged more regularly, and the formation of cells was just like old alveolar. The new bone showed higher quality but lack of thickness. New cementocyte, cementoblast and lamellar structure were seen in several slices of CGF, CGF+ESHT and CGF+Bio-Oss group. According to statistical analysis, heights of new bone in CGF, CGF+ESHT, CGF+Bio-Oss groups were significantly higher than that in control group. The CGF+ESHT group and CGF+Bio-Oss group showed no statistical difference, yet they were both significantly higher than CGF group.Conclusion:CGF can be used alone to promote periodontal tissue regeneration. ESHT and Bio-Oss both enhance CGF’s regenerative effect to the analytic extent. There may be a consistence between CGF+ESHT and CGF+Bio-Oss. The results further suggest that early stage of healing tissue derived from the tooth socket combined with CGF can be a better way to regenerate periodontal tissue defect due to their non-antigen characteristic.. |
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