Investigations on the Influencing ofthe Subgingival Microflora in ChronicPeriodontitis

AIM: The aim of the present study was to investigate changes in the subgingival flora in adults with chronic periodontitis undergoing orthodontic fixed appliance therapy. PATIENTS AND METHODS: In seven adult patients who had undergone nonantibiotic periodontal pretreatment, the subgingival bacteria were subjected to microbiological examination and the number of periodontopathogenic organisms was determined before (T1: prior to treatment being started), during (T2: 6 weeks after orthodontic treatment was started) and after the end of orthodontic treatment (T3: 6 weeks after removal of the fixed appliances). RESULTS AND CONCLUSION: During the fixed appliance therapy (metal brackets, NiTi archwires, stainless steel archwires), a marked reduction was observed in the total bacteria count from the subgingival pocket despite the clinical periodontal parameters remaining almost unchanged. However, the total count of some highly pathogenic bacteria rose again slightly after the end of treatment. We attribute the marked improvement in the periodontopathogenic bacteria spectrum under fixed appliance therapy with metal brackets, NiTi archwires and stainless steel archwires to metal corrosion entailing the release of primarily nickel ions, which have a toxic effect on bacteria and thus enable the regeneration of the physiological bacterial flora. In none of the patients was a deterioration of the periodontal status observed during and after fixed appliance therapy.