Periodontal micro-organisms detected at baseline and two years later in the women with (HRT) or without (non-HRT) hormone replacement therapy. Graph A shows the results of women with the Community Periodontal Index for Treatment Need (CPITN) score 3, indicating the existence of ≥ 4 mm deep periodontal pockets, and graph B of those with CPITN score 4, respectively, indicating ≥ 6 mm periodontal pockets. A.a. = Aggregatibacter actinomycetemcomitans, P.g. = Porphyromonas gingivalis, P.i. = Prevotella intermedia, P.n. = Prevotella nigrescens, T.f. = Tannerella forsythia, T.d. = Treponema denticola. The asterisks show statistically significant differences between baseline and follow-up samples (*p < 0.05, **p < 0.01; #p = 0.07).