evaluation of subgingival dental plaque microbiota changes in fixed orthodontic patients with syber green real time pcr

introduction: one of the most common problems we confront in orthodontic therapy is periodontal diseases. initial factor which causes these diseases is colonization of anaerobic microorganisms in subgingival plaque. technically, local environmental changes related to orthodontic band and brackets may influence the bacterial species in periodontal plaque. however, it seems necessary to assess variations in subgingival plaque caused by orthodontic appliances. the aim of this study was to investigate changes in subgingival microbiota and clinical parameters before and after bracket placement. methods: clinical parameters including probing depth (pd), plaque index (pi), clinical attachment level (cal), bleeding on probing (bop) and gingival index (gi) were recorded and subgingival microbial samples were collected in 30 people aged between 13 and 25. as a control group, 15 persons getting matched as to their age and sex with no need to orthodontic treatment were opted using specific primers, syber green real-time pcr was carried out in order to determine bacterial flora in stored samples. all mentioned procedures were reassessed in experimental group and in control group three months after band and bracket bonding. a descriptive analysis was conducted, and paired t test and wilcoxon test were used for differences between groups (p< 0.05). results: no changes in clinical attachment level were observed, but scores for bleeding on probing, plaque index, and gingival index increased 3 months after bracket placement in experimental group (p< 0.05). prevotella intermedia rose in experimental group after brackets placement compared with control group but actinobacillus actinomycetem comitans and tanerella forsythia proportions did increase. conclusions: treatment with fixed appliances may transitionally raise the growth of periodontopathogenic bacteria and consequently result in gingival inflammatory response but without destructive effect on deep periodontal tissues.