The Effect Of Guided Bone Regeneration On Susceptibility Of Peri-implantitis In Mandibular Posterior Region

Objective:The implants in the guided bone regeneration(GBR)area were analyzed for clinical examination indicators,bone loss on the X-ray edge of the apical slice,and the level of inflammatory factors and proteases in gingival crevicular fluid,and compared with conventional implants.To evaluate the effect of horizontal alveolar ridge bone grafting on the long-term stability and inflammatory susceptibility of the soft and hard tissues around the implant.Methods:A total of 28 patients admitted to the Department of implantology of Dalian Stomatological Hospital from December 2019 to June 2021 were selected.Among them,there were 12 patients with 27 implant dentures(experimental group)who were implanted and repaired Straumann soft tissue level implants(Roxolid(?) SLActive(?)Straumann)after horizontal GBR bone grafting(absorbable collagen membrane combined with 1:1 autogenous bone particles and xenogenous bone replacement materials).There were 16 patients with the same system of implants in the mandibular posterior dental area undergoing conventional implant operation,with a total of 35implants(control group).The patients were recalled after meeting the load for 12-24 months.Clinical indexes of diagonalized soft-tissue level implants with Keratinized width ≥2mm were examined and the probing depth(PD),modified sulcus bleeding index(m SBI)and modified plaque index(m PLI)were recorded.After periapical X-ray examination,Image pro Plus6.0 software was used to measure the amount of marginal bone loss.The gingival crevicular fluid around all implants was collected using filter paper strips of the same specification.Meanwhile,the gingival crevicular fluid of the healthy control natural teeth of the patient was collected and the gingival crevicular fluid of all samples was measured.ELISA was used to detect the content of IL-1β,IL-6,TNF-α,MMP-8,OPG and RANKL.SPSS 26.0 software was used for statistical analysis of all data.Results:The survival rate of both groups after 12-24 months of implant loading was100%.After an average load of 18.70±4.45 months,PD of the experimental group was lower than that of the control group(P < 0.05),while there was no significant difference in m SBI and m PLI between the two groups(P > 0.05).In the experimental group,mesial neck margin bone decreased by 0.60±0.69 mm and distal bone decreased by0.77±0.71 mm.In control group,the proximal and distal changes were 0.15±0.67 mm and 0.15±0.59 mm,respectively.There was significant difference in bone loss at the implant edge between the two groups(P<0.05),and the difference was more significant at the distal edge.The contents of IL-1β,IL-6,TNF-α and MMP-8 in PICF of the experimental group were different from those of the control group in the range of 0.76-4.75pg/m L.However,there were no significant differences in the contents of various cytokines between the two groups and between the implants and healthy natural teeth(P>0.05).There was no significant difference in RANKL and OPG content in PICF between the two groups(P>0.05),but RANKL was slightly lower than that of natural teeth.The level of OPG in the experimental group PICF was slightly higher than that in the control group,and slightly higher than that in the natural teeth.RANKL/OPG ratios of implants and natural teeth were similar in the two groups(P>0.05).In addition,correlation analysis of experimental group data showed that IL-1β,IL-6,TNF-α and MMP-8 presented a significant correlation(P<0.01);the correlation between the amount of margin bone loss and IL-6 and TNF-α content was statistically significant(P<0.05).The amount of marginal bone loss was positively correlated with probing depth and RANKL(P<0.01).Conclusions:In this study,the horizontal guided bone regeneration technique using 1:1autogenous bone/xenograft was used to achieve good clinical results.The history of guided bone regeneration bone grafting resulted in a slightly higher amount of cytokines in the gingival crevicular fluid of the implant,but did not significantly affect the stability of the soft and hard tissues around the implant and the susceptibility to inflammation.