Dark‐pigmented Bacteroides species in subgingival plaque of adult patients on a rigorous recall program

This study was designed to examine human subgingival plaque for the presence of dark‐pigmented Bacteroides (DPB) species in a large adult population that had been following a rigorous oral hygiene and recall program for 2 years. Subjects received scaling and root planing and oral hygiene instructions at the time of entry and then a prophylaxis and/or oral hygiene instructions at frequent intervals. Clinical measurements were determined and microbial flora identified in subgingival plaque. The DPB species were found in 63% of the subjects and 47% of the total sites. The N‐acetyl‐B‐glucosaminidase‐positive DPB species (B. melaninogenicus, B. denticola or B. loescheii), B. intermedius, B. gingivalis and strains of unclassified pigmenting Bacteroides were found in 25, 50, 3 and 40% of the subjects, respectively, and at 15, 35, 2 and 25% of the sites, respectively. Plaque and bleeding indices, probing depth and mean proportions of motile rods and spirochetes were higher at sites with DPB as compared to sites without DPB species. Sites with B. intermedius had higher plaque and gingival indices and greater loss of probing attachment than sites with DPB other than B. intermedius. The prevalence of B. intermedius and other DPB species was high even though subjects were on a rigorous oral hygiene and recall program.