The Correlation Study About The Eight Kinds Of Microorganisms Both In The Peri-implant Gingival Sulcus And Implant-abutment Connections' Inside Under Three Different Kinds Of Connection Modes

Objective In this study,we use qualitative PCR technology with high sensitivity for microbial detection to detect the three implant systems of different implant-anutment connections used at Hangzhou Dental Hospital Oral Implantology Center affiliated to Zhejiang Chinese Medical University currently,to test the positive rates of 8 kinds of microorganisms(Aggregatibacter actinomycetemcomitans,Porphyromonas gingivalis,Prevotella intermedia,Treponema denticola,Fusobacterium nucleatum,Campylobacter rectus,Peptostreptococcus micros,Tennerella forsythensis)at the implant-abutment connection' inside and the peri-implant gingival sulcus,evaluate the differences in detection rates of 8 microorganisms in the peri-implant gingival sulcus and implant-abutment connections' inside under different implant abutment connection modes and compared the bacterial microleakage in different connection modes.To evaluate the difference of detection rate of 8 microorganisms in the gingival sulcus and abutment joint of the patients with preoperative periodontal health and the patients with chronic periodontitis.To understand the correlation between peri-implant clinical examination results(PPD,modified SBI and MBL)after at least 1 year of functional loading and 8 microorganisms in the gingival sulcus and abutment junction around the implant.Methods 1.From July 2011 to January 2018 in Hangzhou Dental Hospital,60 patients who had implantation treatment and completed restoration of prosthetic loading for more than 1 year.Among them,10 patients had multiple implants in their mouths,and one implant was selected by random sampling.There was no loosening of the central screw of the implants in the patients' mouths during the reexamination.There are three implant systems:Straumann BL,Thommen and Bego,with 20 implants in each implant system.A total of 60 implants were including 39 implants(HI)in patients with periodontal health and 21 implants(CI)in patients with chronic periodontitis before planting treatment.The patients with chronic periodontitis perfromed routine periodontal sequence therapy prior to implantation.These 60 implants were all adopted screw fixations.Three different implant-abutment connections were studied:Straumann BL implant system is platform-switched connection(group 1);Thommen implant system is modified butt-joint connection(group 2);Bego implan system is butt-joint connection(group 3).Each group contained 13 implants for patients with periodontal health and 7 implants for patients with chronic periodontitis before planting treatment.2.Clinical parameters such as peri-implant probe depth(PPD),modified peri-implant gingival crevicular bleeding index(modified SBI),calculated the implant marginal bone resorption(MBL)with imageological examination and so on were recorded in all patients.3.Samples for microbiological were obtained from two types of sites:peri-implant gingival sulcus and implant-abutment connections' inside.Then send these samples to Hangzhou Biological Watson biotechnology company to analysis the eight kinds of pathogenic bacteria(Aa,Pg,Pi,Td,Fn,Cr,Pm,Tf)for DNA extracted,qualitative PCR and electrophoresis detection.4.By collection and sorting out the data statistical analysis software SPSS23.0 was used to analyze the data among variables.Results 1.The sum of microbial detection rates in the gingival sulcus and the implant-abutment connections' inside were compared in each group,there were significant differences between group 1 and group 3(P<0.05),which has statistical significance.In group 1,the sum of the detection rates of microorganisms in the gingival sulcus and the implant-abutment connections' inside were lower than those in group 2 and group 3.2.Compared the detection rates of 8 microorganisms in the peri-implant gingival sulcus and implant-abutment connections' inside in each group,Fn in group 1 the detection rates in the gingival sulcus and the connections' inside were significantly different(P<0.05),which has statistical significance.However,there were no significant differences in the detection rates of other microorganisms in the peri-implant gingival sulcus and implant-abutment connections' inside(P>0.05).3.The comparison results between the implants of patients with periodontal health(HI)and the implants of patients with chronic periodontitis(CI)befor planting treatments showed that there was no significant difference in the detection rates of 8 microorganisms in the peri-implant gingival sulcus and implant-abutment connections'insides around HI group and CI group(P>0.05).The detection rates of Pg,Td and Cr in the CI group was higher than that in the HI group.The detection rates of Pi,Fn,Tf in the HI group were higher than that of CI group.4.The comparison results about the peri-implant probing depth(PPD?4mm;PPD>4mm)showed that there was no significant difference in the detection rates of 8 microorganisms in the peri-implant gingival sulcus and implant-abutment connections'insides(P>0.05).The detection rates of Pg,Pi,Td,Cr and Tf in the PPD>4mm group were both higher than that in the PPD?4mm group.5.There was no significant difference in the detection rates of 8 microorganisms in the gingival sulcus and implant-abutment connections' insides between healthy implants and peri-implant mucositis(P>0.05).The detection rate of Fn in the peri-implant mucositis was both higher than that in the healthy implants.6.Compared the two groups between the MBL<1mm group and the MBL?1mm group,the detection rates of Fn in the gingival sulcus and Pg in the connections'insides were significant differences(P<0.05).In the MBL?1mm group,the detection rates of Fn and Cr were both higher than that in the MBL<1mm group.The detection rate of Pg in the MBL?1mm group was both lower than that in the MBL<1mm group.Conclusion 1.As a prevalent phenomenon,micro-leakage occurred at dental implant-abutment interface can not be eliminated.Bacterial leakage occurred in all implants after 1 year of functional loading.2.There were differences among implants with different connection types,and the platform switched connection mode may have better resistance to bacterial microleakage.3.The patients with a history of periodontitis can be prevented from peri-implantitis by systematic preoperative periodontal treatment and daily maintenance.The stability of the implants was the same as that of the implants in periodontal healthy patients.4.After at least 1 year of functional loading,the implants' clinical manifestations were correlated with the detection rates of 8 microorganisms.Pg,Pi,Td,Fn and Pm may be associated with increased probing depth.Fn may be associated with peri-implant mucositis.Fn and Cr may be associated with peri-implant bone resorption,but Pg may be not associated with peri-implant bone resorption.