| Objective: Mandibular wisdom teeth,also known as the third mandibular molars,are located at the end of the dentition.As people eat more and more refined food,the degradation of the jaw bone can not keep up with the degradation of the amount of teeth.The jaw bone is not enough to hold so many teeth,which often leads to the obstruction of wisdom teeth by soft tissue or hard tissue.Impacted wisdom teeth can trigger A wisdom tooth pericoronitis or adjacent to the second molar teeth and periodontal disease,and improved the rich Platelet fibrin(Advanced-Platelet-rich fibrin,A-PRF)is the second generation of Platelet concentrate products rich Platelet fibrin(Platelet rich fibrin,PRF)of the modified version,on the basis of PRF,adopt the method of low delay,get more loose structure,is conducive to cell proliferation and differentiation.A-PRF is made from the autologous blood of patients,without any biological agents added,eliminating the risk of immune rejection and infection,and there is no safety risk.In addition,the preparation process is simple and easy to operate,and the price is low,easy to be promoted in clinical.In this study,modified platelet-rich fibrin was extracted to investigate the effect of A-PRF gel on distal bone defect repair of adjacent second mandibular molars after extraction of mandibular wisdom teeth.Methods: case selection and grouping: patients with unilateral vertical or horizontal impacted mandibular wisdom teeth admitted to the department of stomatology of Anqing hospital affiliated to Anhui medical university from November 2017 to April 2018 were selected.According to the serial number of patients,the odd-numbered patients were in the A-PRF group,and the even-numbered patients were in the control group,with 24 patients in each group.A-PRF made from the patients' autologous blood was implanted into the tooth extraction wound at the same time after the tooth extraction operation in the A-PRF group,while the tooth extraction wound in the control group did not know any substance after the tooth extraction operation.Experimental methods: All 48 patients with preoperative shot full of surface fault andcone CT(cone beam computed tomography,CBCT),preoperative assessment of the mandibular wisdom teeth and alveolar bone defect types,root,giving out patients with mandibular teeth under local anesthesia,A-PRF set out in the mandibular teeth of autologous venous blood collected at the same time,to 1500 r/min speed centrifugal 14 minutes,get altered platelet fibrin gel,after mandibular teeth pull out,will be altered platelet fibrin gel rich fill in after tooth extraction.Waitting for blood filling in the alveolar fossa,close suture the wound with half 8-word cross stitch method,bite the gauze roll for half an hour to stop bleeding.The surgical method of the control group was the same as that of the A-PRF group,and no substance was injected into the tooth extraction wound.The patients were re-examined 1,2,3 and 4 months after the operation to check the healing of the alveolar fossa and the periodontal condition.The patients were examined by periodontal examination 4 months after the operation to evaluate the periodontal condition of the second molar.Imaging analysis: The sagittal plane images of full-mouth curved tomography and CBCT were imported into the digital medical image analysis system Motic medical 6.0,and the gray values of the two regions,the bone defect area and the blank area were measured.The gray values of the bone defect area and the blank area were subtracted,and the obtained values were the actual gray values.Manual gray value analysis mode was selected in the system to select the distal bone defect area of the second mandibular molar and set the area size as(3*3)cm2.The system could automatically calculate the average gray value of the area and reflect the bone density of the area.The mean gray value of the distal alveolar bone after the second molars was recorded.CBCT examination was performed to record the mean values of the buccal axial Angle,lingual axial Angle of the distal alveolar bone of the second molars and the vertical distance from the top of alveolar bone crest to the junction of enamel dentin,and the difference between the two records was recorded as bone gain.Statistical methods: SPSS21.0 statistical software was used to compare the relationshipbetween gender distribution,left and right side parts,and type of third molars induced by chi-square test in the two groups.Non-parametric rank sum test was used to compare age and type of third molars induced by the two groups.Before the analysis,the normality test was carried out for all the imaging measurement data,and the two independent samples t test was used for the data conforming to the normal distribution.Nonparametric rank sum test is used for unnormal distribution data.P<0.05 was statistically significant.Results: A total of 48 patients were collected in this study.None of them were lost during the treatment,and all of them were included in the analysis of experimental results.All patients were aged between 18 and 59.26 males and 22 females;25 on the left and 23 on the right.There were 24 cases in A-PRF group and 24 cases in control group.There was no significant difference between the two groups in gender distribution,types of implantation and left and right side parts(P>0.05),and no statistical significance was found between the two groups in age and types of implantation(P>0.05).Statistical analysis showed that there was no statistical significance between the A-PRF group and the control group in the distal periodontal probing depth of the adjacent second molars.The results of full-mouth curved tomography and CBCT examination and measurement at the fourth month after surgery were analyzed,and the difference of ashes degree between the A-PRF group and the control group was statistically significant.The difference of bone gain between the A-PRF group and the control group was statistically significant.Conclusion: Modified platelet-rich fibrin can promote bone formation and promote bone healing.Implantation of modified platelet-rich fibrin at the same time of extraction of the third molars can effectively promote the regeneration and repair of the distal bone tissue of the second molars. |
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