Clinical Research Of Platelet-rich Fibrin (PRF) Combined With Apically Repositioned Flap (ARF) To Enhance The Width Of Keratinized Tissue In The Edentulous Area

Objective:In order to enhance the keratinized tissue in the edentulous area,the clinical effect of Platelet-rich fibrin(PRF)combined with Apically repositioned flap(ARF)will be observed.Compared to the difference results of ARF with Free Gingival Graft(FGG)and ARF only and based on the effect of the keratinized tissue growth,the ability of PRF membrane to induce gingival soft tissue regeneration was evaluated.Method:Fifteen patients were selected from the first hospital of Shanxi Medical University,who had received treatments at the Department of oral from December 2016 to September 2017.There are 6 males and 9 females,aged from 29 to 63 years old and the average age is 49.2 years old.Because of lacking keratinized tissue(< 2mm)in the edentulous area,they are provided a good soft tissue foundation on the purpose of the later implant and repairment.There were 5 cases in group ARF,5 cases in group ARF+PRF and 5 cases in group ARF + FGG.The width and thickness of keratinized tissue were compared preoperation,immediately after operation,1 month after operation and 3 month after operation.SPSS 22.0 analysis was used,and differences were considered statistically significant at P < 0.05.Result:1.Fifteen patients were healed well,and no infection occurred.The patients were all revisited on time.2.The width of keratinized tissue in ARF group,ARF+PRF group and ARF+FGG group are changing with each measured time in the clinical observation.The width of keratinized tissue increased in different degrees in 3 months after operation compared with preoperation.The gingival thickness of ARF+FGG group increased obviously.3.Data statistical results(1)The repeated-measures of ANOVA was used to analyze the width of keratinized tissue in the three groups in each measure time.The data is satisfied with the mauchly's test of sphericity(P=0.498).Repeated measurement variance analysis showed that the width of keratinized tissue in different groups was significant difference(P < 0.001).The width of keratinized tissue at different measure time is also difference(P < 0.001).There was an interaction effect between time and groups(P < 0.001).The width of keratinized tissue was closing in the preoperation and immediately after operation,and the trend decreased in 1 and 3 month after the operation.The decrease trend of group FGG was the slowest,followed by group PRF.(2)?WKT(width of keratinized tissue in measured time / preoperative)was analyzed by repeated-measures of ANOVA in three groups postoperation.The results of variance analysis using Greenhouse-Geisser(P=0.640)correction showed that there was a interaction effect between time and groups(P < 0.001).The simple effects of ?WKT showed that there was no significant difference at the postoperative time(F=0.471,P=0.636).The significant difference of ?WKT was showed at 1 month after operation(F=36.200,P<0.001).Multiple comparisons show that ?WKT of FGG were compared with the other two groups showed significant difference(P < 0.001);PRF compared with ARF,the difference was significantly significant(P=0.047).There was a significant difference of ?WKT at 3 month after operation(F=50.889,P<0.001).Compared with the other two groups,the difference of FGG was significantly significant(P < 0.001);and compared with ARF,the difference of PRF was significantly significant(P=0.038).After 1,3 month after operation,the ?WKT in ARF,ARF+PRF and ARF+FGG are increasing in turn.(3)The variation of gingival thickness ?GTH in three groups(3 month after operation / preoperative)was analyzed by Kruskal-Wallis test.The distribution of ?GTH among the three groups is not identical(P=0.009).The results between each group showed that there was a significant difference between FGG and other two groups(P<0.05).PRF compared with ARF the difference was not significantly significant(P > 0.05).Conclusion: 1.ARF,ARF+PRF,ARF+FGG can increase the width of keratinized tissue,and the increment is increasing in turn.2.After 3 month of the operation,the width of keratinized tissue in group ARF+PRF was a little more than that in group ARF,suggesting that PRF can promote the regeneration of soft tissue.3.After 3 month of the operation,there is no obvious increase of gingival thickness in ARF+PRF,which need to be observed further.