Variation of suspected periodontal pathogens and clinical periodontal index in patients before and after fixed appliance bonding

Objective: Through the examination of flora in gingival marginal plaque and periodontal status at different time intervals before and after fixed appliance bonding,in order to analysis the dynamic variation of suspected periodontal pathogens and clinical periodontal index.Methods:18 orthodontic subjects were selected.Plaque index(PI),gingival index(GI),probing depths(PD) and bleeding on probing(BOP) of observed teeth,16 and 41,were examined and gingival marginal plaque samples were collected at different time intervals:baseline,1 months,3 months,6 months after the bonding.The detective amount and detective ratio of suspected periodontal pathogens were assayed by cultivation,respectively.Results:Compared with baseline,the detective amount and detective ratio of black-pigmented gram negative anaerobic rod(BPAR) increases at both observed teeth during the survey( P 0.05),and eubacterium,campylobacter,bacteroides and prevotella increase at 41 ( P 0.05).The total amount of the bacteria doesn't show significant changes.Gingival index(buccal side) of 41 decreases.Conclusion:In spite of strict oral hygiene instructions the amount of suspected periodontal pathogens also increases after fixed appliance bonding,although the dental plaque could be effectively controlled.