Comparative Study Of Periodontal Regenerative Potential Of Advanced Platelet Rich Fibrin And Concentrated Growth Factor

BackgroundPeriodontitis is a chronic infective disease with the bacteria in dental plaque as its main pathogenic factor,which exhibits a progressive destruction of the periodontal supportive tissue,leading to the gingival inflammation,periodontal pockets formation and alveolar bone resorption,thus eventually resulting in the migration and even the loss of tooth in adults.Also,it is regarded as a risk factor for systemic diseases such as cardiovascular disease,diabetes,rheumatoid arthritis,inflammatory bowel disease,etc.Accordingly,how to reconstruct and regenerate the periodontal tissue remains an urgent but hard tissue.As a common clinical choice,guided tissue regeneration(GTR)does make some effects on repairing periodontal defects,but it still has shortages of limited indications,poor efficacy and inadequate regeneration activity.Currently,platelet concentrates(PCs)extracted from autogenous blood extraction have been paid extensive attention due to their safety,immunogenicity,growth factors enrichment and high regenerative activity.In our study,APRF and CGF,the latest 3rd generation PCs,were adopted as research objects to observe the external and internal structure,the growth factor content and the release regularity;meanwhile,APRF and CGF were applied to clinical regeneration surgeries respectively to explore the promotion of periodontal defects repair and the application value in periodontal regeneration.Besides,by comparing the actual regeneration efficacy of APRF and CGF provide,it might provide reference to the correct choosing of PCs applications and new technology means for clinical periodontal regeneration treatments.Part 1Comparative Study on the Contents and Release Rules of KeyGrowth Factors in APRF/IPRF/CGFObjective:To compare the differences of fibrin structure and growth factor contents between APRF and CGF(2 kinds of the 3rd generation PCs),and explore the release rules of PCs with different characters(gel and liquid).Methods:The gel-like APRF,CGF and liquid version of IPRF were prepared by the standard centrifugal scheme,and the whole blood was conventionally centrifuged to obtain gel-like PC as control.The morphology,texture and internal fibrin structure of each group were observed with visual inspection and scanning electron microscope.Moreover,4 kinds of PCs with addition of the DMEM medium were incubated at 37? and the supernatants were collected after 1,3,7 and 14 days to detect the levels of growth factors PDGF-AB,TGF-beta,VEGF and BMP-2 by ELISA.Results:The visual inspection images showed that the APRF and CGF gel were apparently denser compared with the control PCs.Besides,among 3 groups,the CGF gel possessed the highest density,the smoothest surface and the clearest demarcation between the fibrin layer and the erythrocyte layer.Similarly,the observation of scanning electron microscope revealed that the fiber network of APRF and CGF gel were denser and more orderly than that of the control PCs,and the fibrin interweaving degree of APRF gel was slightly looser than that of CGF gel.In addition,the results of ELISA indicated that the release of PDGF-AB,TGF-beta and VEGF in APRF and CGF groups were clearly higher than those in the control group;APRF and CGF groups have approximate total release contents of PDGF and TGF-beta,while the total release of VEGF in APRF group was evidently higher than that in CGF group.What's more,the release of TGF-beta 1 in APRF group was significantly higher than that in CGF group after 7 days.As for the IPRF group,the initial growth factor release was relatively high,especially PDGF-AB.Conclusion:The APRF and CGF gel had more stable and ordered structure than those PCs obtained by conventional centrifugation.Although the APRF gel had looser fibrin network than the CGF gel,but it presented larger amounts and more sustained release in the later period,suggesting that the APRF gel may have better structure and function in promoting tissue repair and regeneration.Part 2Comparative Study on the Promotion of Periodontal DefectRegeneration via GTR combined with APRF/CGFObjective:At present,there are few studies on APRF and CGF in the clinical application of periodontal regeneration.In this study,APRF and CGF were applied in 2 forms(gel and membrane)with GTR in order to explore the application value and different effect between APRF and CGF in periodontal regeneration surgeries.Methods:From May,2014 to May,2018,30 patients with periodontal bone defects,divided into APRF+GTR group and CGF+GTR group according to the different PCs used during the operation,underwent GTR/bone grafting combined with APRF or CGF.The periodontal examination and CBCT were performed 6 months before and after the operation.Changes of clinical indexes and radiological values of the periodontal depth(PPD),clinical attachment level(CAL),radiological bone level(RBL)and intrabony component(IC)depth were measured and analyzed.The filling rate of defect was calculated and the therapeutic effect was compared between 2 groups.Results:The PPD and CAL of the 2 groups were significantly improved.On average,the PPD decreased by 4.33 mm and 4.60mm while CAL increased by 4.20 mm and 4.40 mm,for group APRF+GTR and group CGF+GTR respectively.It was observed with CBCT that filling implants were stable in the alveolar bone defect and the defect bottom rose higher 6 months after treatments,which were reflected by the quite good filling rate of 87%and 84%,and the declining IC depth of 5.11mm and 4.71mm,respectively.x Overall,there were no significant differences between the two groups in the clinical indexes and radiological values.Conclusion:GTR combined with APRF/CGF was able to achieve good clinical results to repair periodontal bone defects.Undoubtedly,APRF and CGF could help to improve curative effects of conventional regeneration surgeries.APRF and CGF PCs had no significant differences in the efficacy of periodontal regeneration for now,which still needs larger samples for further prospective trials.