[The changes of subgingival microbials during periodontal maintenance in patients with gingivitic and wearing fixed orthodontic appliances].

OBJECTIVE: To investigate the microbiological changes of subgingival microbials in patients with gingivitis and wearing fixed orthodontic appliances. METHODS: 48 subjects (10 to 17 years old) with gingivitis, and wearing fixed orthodontic appliances, were divided randomly into three groups (placebo, NS and CH). Placebo group had normal saline mouthrinse; only and no oral hygiene instruction (OHI). The NS group had OHI and normal saline mouthrinse; The CH group had OHI and 0.12% chlorhexidine gluconate mouthrinse. Bacterial examinations were carried out on baseline, one week, one month and three months after scaling. The bacterial examination was carried out. The percentage of coccus, bacillus and spirochete was calculated. RESULTS: In placebo group and NS group, the percentage of coccus increased up to the third examination then dropped down. The spirochete's percentage changed inversely. CH group maintained an increasing trend in coccus' percentage and decreasing trend in spirochete's percentage. The percentage changes of coccus and bacillus between placebo group and CH group are statistically significant (P < 0.05). CONCLUSIONS: During the three-month examination, the CH group had better microbiologic change than the other two groups.