Microbiological Study On Subgingival Plaque Of Dental Implant

Objective: To compare the main pathogenic bacterias and the clinical indicators of the implants in patients with a history of periodontitis and normal patients. Provide microbiology theories for regular maintenance of the implants .Methods: Collect 40 implants in 31 patients and divide them into two groups: group A—the experimental group, 20 implants of patients with a history of periodontitis; group B—the control group, 20 implants in healthy patients. Evaluate, in the four stages of one month, 3 months, 6 months and 12 months after restoration, their Plaque Index (PlI), Gingival Index (GI), Gingival Bleeding Index (GBI),and Probing Depth (PD). Subgingival plaque samples were taken at the four stages .Culture the anaerobian, black-pigment bacteria, F.nucleatum(F.n), Actinomyces viscosus,(A.v). of the samples in their Selective medium. Record the datas and analyze them statistically.Results : The horizontal comparison of group A and group B shows that the value of anaerobian,black-pigment bacteria,GI and PD in group A is statistically different from group B. Other tested indexes show no statistic difference. One month after restoration, the value of anaerobian, black-pigment bacteria in group A is significantly different from group B. In the longitudinal comparison of the two groups, the value of anaerobian, black-pigment bacteria, F.n is increasing as time extended. From the 1st to the 3rd month, their value increases most obviously and then becomes stable after 6th month. The value of anaerobium, black-pigment bacteria, F.n and A.v is statistically different between the 1st and the 3rd month, the 3rd month and the 6th month, but they show no statistical difference between the 6th and 12th month. Other tested indexes show no statistic difference.Conclusions: From the horizontal comparison: The microbiological indexes of patients with a history of periodontitis are higher than normal patients, a large number of bacteria may have been attached at 1st month after restoration . So we should pay attention to the maintenance of the patients with a history of periodontitis. It's important to do cleaning early and do long-term oral health education to prevent bacteria adhesion,so as to increase success rate of such implant patients. From the longitudinal observations: For periodontal healthy patients, pathogens grow fast from 1st month to 3rd month .So we should pay attention to the cleaning of the implants at this time. Microbiological examination is more sensitive than clinical examination, and can detect the inflammatory trend of implants early. If adding microbiological examination to the regular reexamination, early subgingival microflora changes can be found. Then we can control it before bone resorption and peri-implantitis, prevent hard and soft tissue injury around the implant.