[Evaluation of dark field microscopic techniques and correlation between DFM data and clinical periodontal parameters].

Two subgingival sampling methods (curette and washing) used in DFM were compared. The effect of repeated washing sampling to subgingival microflora were also evaluated. These results demonstrated that washing techniques and curette could be used alternatively. No significant change of subgingival flora were observed after repeated washing sampling were used. 204 bacterial samples obtained from different periodontal status were analysed by DFM. The data showed that there was significant positive correlation between spirochete%, motile rods % and P1I. BI. PD, both incross-sectioned and longitudinal analysis (22 samples DFM assessed before and after periodontal treatment). Also, our data suggested that it was impossible to establish a threshold level of microorganism to diagnose periodontal diseases only by DFM analysis.