Subgingival bacterial burden in relation to clinical and radiographic periodontal parameters

This cross-sectional study characterizes the association between subgingival bacterial profile and periodontal parameters in patients assigned to coronary angiography because of cardiologic problems, which may affect the oral microbiota.

Pooled subgingival bacterial samples were collected from 477 dentate individuals during the oral examinations, along with periodontal probing depth (PD) and assessments of bleeding on probing (BOP) and radiographic alveolar bone loss (ABL). The checkerboard DNA-DNA hybridization assay was used to determine the levels of 29 oral bacteria, which were divided into three bacterial complexes.

All bacterial combinations from the etiologic bacterial group and each species from the red complex were significantly associated (P <0.001) with grade of ABL. The prevalence of the etiologic bacterial group and the level of each species were also associated strongly with the proportion of sites with PD 4 to 5 mm and ≥ 6 mm, BOP, and ABL, except Aggregatibacter actinomycetemcomitans. Levels of Gram-negative oral bacteria correlated significantly with those of Gram-positive species (r = 0.840, P <0.001). In multiple logistic regression analysis, the prevalence of the etiologic bacterial group, levels of Gram-negative bacteria and Treponema denticola, and the prevalence of Porphyromonas gingivalis and T. denticola associated significantly with ABL, whereas other bacterial complexes and levels of Gram-positive species did not.

Although levels of Gram-negative and -positive species paralleled periodontal parameters, only the species considered etiologic were associated with ABL.