FIG 2.

Periodontal microbiome α-diversity remains similar among cohorts, yet community structure is unique. α- and β-diversities of periodontal microbial communities for conventional cigarette smokers, e-cigarette users, and nonsmokers are shown. Sample numbers are provided in Materials and Methods. α-Diversity between visits tended to increase within a cohort (A) (paired-sample Wilcoxon). The degree of change in α-diversity measures between visits (v2 – v1) for a given cohort was not significantly different between the cohorts (B) (Mann-Whitney U test). When visits were merged within a cohort, no significant differences in α-diversity were observed (C). Mean and SEM are shown for panels A to C; box indicates the interquartile range of the data. β-Diversity of periodontal microbial communities was significantly different between cohorts (PERMANOVA) (D). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. A Venn diagram depicts shared and unique amplicon sequence variants (ASVs) among the cohorts; percentages of total ASVs are in parentheses (E).