Bacteria prevalence in a large Italian population sample: a clinical and microbiological study

The present study detects those bacterial species which are more strongly related to bleeding on probing, suppuration and smoking in periodontal-affected patients. Nine hundred and fifty-one patients with periodontal diseases were admitted to the Department of Periodontology and Implantology, Dental School of Bologna University where they underwent microbiological tests for six periodontal pathogens (Actinomyces actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Treponema denticola, Fusobacterium nucleatum and Tannerella forsythia). Cluster analysis explored the variables that mostly influence both the presence and absolute\relative bacterial load. Logistic regression and multivariate linear regression quantifies these relations. The probability of recovering bacteria belonging to the Red Complex is greater by 25-48% in presence of bleeding on probing. When probing depth is less than 3 mm the probability of presence of each bacterial species is inferior in comparison with depth >6 mm both for Red Complex (of 20-37%), the Orange complex (of 41-61%) and Actinomyces actinomycetemcomitans (46%). Total bacterial cell count increases with pocket depth above all for the Red Complex. As Treponema Denticola and Tannerella Forsytia presence is associated with bleeding on probing and Prevotella intermedia presence with suppuration and smoking. The examination of these three as indicators of periodontitis evolution is suggested.