Research Of Subgingival Microecosystem Around Dental Implant In Different Conditions

Microorganism is the most important factor in subgingival microecosystem around dental implant. In peri-implant sulcular fluid (PISF), there are a lot of things could be exchanged between host and microorganisms, such as substance, energy and information. Researches show that late failures of dental implants are closely related to implant infections. Microorganisms play an important role in the process of implant infections. At present, many researches focus on detecting pathogens around failed implants. However, there are a few researches about proportion of subgingival microorganisms around implants which suffering from infections, but not failed. On the other hand, in the process of transmission of inflammatory cell signal, intercellular adhesion molecule-1(ICAM-1) participates in directional transfer of leucocyte and lymphocyte. By now, there are few reports about expression of sICAM-1 inPISF and relationships between sICAM-1 and peri-implant pathogens. PurposesBy investigating the relationship between beneficial bacteria and pathogens around infectious implants, the expression of ICAM-1 in PISF and pathogens' influence on ICAM-1, we wish to find a way to diagnosis and treat implant infections early.Contents and Methods1. Using culture and PCR technique to analyze the proportion of subgingival microorganisms around implants which having been implanted more than two years, and investigate the influence of different peri-implant pocket depths (PPD) and implant types on settlement and proportion of subgingival microorganisms around implants.2. Researching the changes of clinical parameters and subgingival microorganisms around infectious implants after non-surgical treatments.3. Using periopaper strips to collect PISF and an ELISA technique to measure the levels of sICAM-1 to investigate the relationship between sICAM-1 and pathogens.Results1. The proportion of gram positive facultatively anaerobic oral Streptococcus in subgingival microorganisms around implants among health, peri-implant mucositis and peri-implantitis group is 55.49%, 39.45% and 31.31% respectively. Also, proportion of Actinomyces is 17.34%, 13.24% and 9.30%. Proportion of gram negative anaerobic rods is 13.80%, 36.75% and 50.22%. The proportion of gram positivefacultatively anaerobic oral Streptococcus and Actinomyces in healthy implants are significantly higher than that in inflammatory implants (P< 0.01) , but the proportion of gram negative anaerobic rods in healthy implants are significantly lower than that in inflammatory implants (P< 0.01) . The proportion of Strepotococcus sanguis (S.s) in healthy implants is significantly higher than that in inflammatory implants (P^O.01) and Veillonella parvula (V.p) is also significantly higher than that in implants with peri-implantitis ( P < 0.01 ) . However, the proportion of Fusobacterium nucleatum (F.n), Prevotella intermedia (P.i), Prevotella nigrescens (P.n) and Porphyromonas gingivalis (P.g) in healthy implants are significantly lower than that in inflammatory implants (P<0.05) .2. The proportion of Strepotococcus sanguis (S.s) in these implants with PPDOmm is significantly higher than it in those implants with PPD^3mm (P<0.01), but F.n is contrary. P.i in these implants with PPD <3mm is significantly lower than it in those with PPD^5mm(P<0.01). P.g in these implants with PPD^5mm is significantly higher than it in those implants with PPDOmm (P<0.01) .3. The proportions of gram positive facultatively anaerobic oral Streptococcus, Actinomyces and gram negative anaerobic rods in subgingival microorganisms around healthy Frialit II and Hoist implants are 54.15%, 18.38%, 13.79% and 50.65%, 17.51%, 14.13% respectively. The proportions of the three kinds of bacteria in inflammatory Frialit II and Hoist implants are 31.08%, 15.88%, 40.47% and 28.42%, 13.46%, 48.79% respectively. There are no significant difference between healthy Frialit II and Hoist implants, also betweeninflammatory Frialit II and Hoist implants (P>0.05) .4. Applying the combined treatment, the clinical parameters and bacterial quantity after 4 weeks are significantly lower than those before treatment (P<0.05) . The proportions of gram positive facultatively anaerobic oral Streptococcus went up from 30.69% -to 64.27% after treatment 4 weeks (P<0.01) , and the proportion of gram negative anaerobic rods went down from 47.04% to 15.25% after treatment 4 weeks (P<0.01) . The proportions of F.n and P.n after treatment 4 weeks are significantly lower than those before treatment (P<0.05) .5. In PISF , the levels of sICAM-1 in healthy and non-plaque adhesion implants are significantly lower than that in inflammatory and plaque adhesion implants (P<0.05) . The level of sICAM-1 is significantly higher in only detecting F.n group than that in detecting F.n and P.g or none of this two pathogens being detected (P<0.01).Conclusion1. The dental implant infections result from the unbalance between gram positive facultatively anaerobic oral Streptococcus and gram negative anaerobic rods. Increasing with the degree of inflammation, the proportion of gram positive facultatively anaerobic oral Streptococcus goes up and gram negative anaerobic rods goes down.2. The peri-implant pocket depth has important influence on the proportion of subgingival microorganisms. The depth of 3 to 5mm indicates that peri-implant tissue may be in a state of sub-health. The pocket which is beyond 5mm could be in favor of pathogens growing.3. Whether peri-implant tissue is in state of health or in state ofinflammation, the proportion of subgingival microorganisms around the Frialit II implant is similar to that of Hoist implant. It doesn't show that the type of implant is related with the proportion of subgingival microorganisms.4. The combined treatment has good effect on early infectious implants. Properly cleaning implant could control plaque and supragingival and subgingival scaling natural teeth around implants could maintain the effect of treatment. 2% HCI-minocycline could improve the clinical syndromes rapidly.5. Whether peri-implant tissue is in state of health or in state of inflammation, sICAM-1 could be expressed in PISF. Plaque accumulation might trigger the up-regulation of sICAM-1 levels; and the onset of inflammation would enhance the up-trend. Microorganism is one of the important factors which regulating the expression of sICAM-1 in PISF. F.n might up-regulate expression of sICAM-1. P.g might down-regulate it.