OBJECTIVEThe study is to investigate the microbial composition of interdental and subgingival plaques of periodontitis patients with or without malodor, to explore the relationships between periodontitis and oral malodor.

METHODS20 patients of periodontitis with malodor were chosen from 210 patients of periodontitis, and the clinical parameter of plaque index (PLI), gingival bleeding index (GBI) and probing depth (PD) were measured and compared with the control group which had periodontal disease without malodor. During the experiment, the interdental and subgingival microbial samples in both groups were collected and sent to anaerobic culture for 48 hrs, then the total CFU/ml of each sample were counted, and each type of bacteria was separated and identified. All of the data were analyzed by using the statistical software SPSS 10.0.

RESULTS(1) There were no satistical differences on PLI, GBI, PD between experimental group and control group. (2) The percents of leptospira in both interdental and subgingival plaques of test group were significantly higher than that of the control group (P < 0.01). (3) Either the interdental or in subgingival plaques, the count results of CFU/ml were similar in both groups (P > 0.05). (4) The proportions of malodor producing anaerobic bacteria in interdental gingival plaque, such as P. gingivalis and Veillonelia, were singnificantly different between test group and control group.

CONCLUSIONThe proportions of VSC's producing anaerobic bacteria in interdental gingival plaque may be play the significant roles in oral malodor. Further studies should be taken to elucidate the relationship between malodor and periodontitis.