Peridontopathogenic key species in correlation to the current classification system.

Objective: The present in-vivo-study aimed on identifying periodontopathogenic key species in correlation to the current classification system. It was evaluated if there is an association in frequency to single periodontitis stages and grades.

Materials and methods: The study included 100 patients that were assigned to 4 test groups (periodontitis stages I-IV) and one healthy control group, each n = 20. Samples were collected from the deepest pockets of each sextant and analyzed for: Fusobacterium nucleatum (F.n.), Aggregatibacter actinomycetemcomitans (A.a.), Porphyromonas gingivalis (P.g.), Tannerella forsythia (T.f.), Treponema denticola (T.d.) and Enterococcus faecalis (E.f.).

Results: Among all samples, F.n. was most common (98%), followed by T.f. (73%), T.d. (66%), P.g. (45%), A.a. (12%) and E.f. (3%). Controls showed no P.g., A.a. and E.f.. In stage I T.f. (p < 0.001) and T.d. (p = 0.022) were significantly more frequent. In stages II and III, P.g., T.f. and T.d. were significant (p < 0,001). In stage IV, A.a. (p = 0.003), P.g., T.f. and T.d. (p < 0.001) occurred with significant higher frequency. Grade C was more common among stage III and IV (20%) as compared to stage I and II (2.5%). Patients diagnosed with stage IV and grade C, showed significant association to A.a. (p = 0.001) and P.g. (p = 0.021).

Conclusions: The present investigation proved significant correlation between periodontopathogenic key species, disease severity and progression risk. A.a. and P.g were most frequently in stage IV and grade C.

Clinical relevance: Microbial analysis provide additional information in regard to the classification of periodontitis.