FIG 1.

Clinical measures validate patient inclusion and demonstrate disease status and progression in specific cohorts. (A) Patient breath carbon monoxide levels in parts per million, saliva cotinine concentration, and the average distance from the free gingival margin to the depth of the pocket (pocket depth); sample number is given below cohort designation. Kruskal-Wallis H with post hoc Dunn’s test was performed, with multiplicity-adjusted P values reported. **, P < 0.01; ***, P < 0.001; ****, P < 0.0001. On each visit, patients were evaluated for the degree of periodontitis, as described by Xu et al. (7) (B). CS, conventional cigarette smokers; ES, e-cigarette users; NS, nonsmokers. Number of subjects is given below each cohort.