In the present study, detection patterns of subgingival Porphyromonas gingivalis (Pg), Prevotella intermedia/nigrescens (Pi/n), Tannerella forsythia (Tf) and Treponema denticola (Td) were analysed, using commercially available species-specific DNA probes (DMDX/PathoTek, Switzerland) in 16 untreated periodontitis patients (5-7 non-adjacent sites per subject) before and one month after mechanical non-surgical periodontal therapy. The detection patterns of the pathogens at the two time points were studied using configural frequency analysis (CFA) and Stuart-Maxwell χ2 test. All subjects showed favourable clinical treatment responses. Prevalence of all microbes followed was significantly reduced after treatment. CFA identified: (i) two statistically significant configural types at both time points: co-detection of Pg, Pi/n, Tf, Td, and none of the four pathogens detectable (Holm's criteria p = 0.003); and (ii) one statistically significant configural anti-type post-treatment: reduced detection pattern of Pi/n alone (Holm's criteria p = 0.004). For many of the pre-treatment sites with Tf, Pg, Pi/n, and Td configural type, all these periodontopathogens were undetectable one month after treatment (p < 0.001, McNemar's post hoc analysis with Bonferroni adjustment). Within the limitations of this study, the results indicated a co-detection of subgingival periodontopathogens Pg, Pi/n, Tf, and Td. Analysis of the subgingival colonisation of these microbes might be a useful adjunct in the assessment of periodontal therapeutic outcomes.
Keywords: Dental plaque/microbiology, periodontitis/microbiology, periodontitis/therapy, statistical model