Figure 2. Species detected by oligonucleotide DNA probes from pooled molar subgingival plaque samples from 28 healthy, 71 early periodontitis 1, and 42 early periodontitis 2 individuals. Health-associated species are at the top of the Fig., whereas species detected more frequently in early periodontitis 2 are at the bottom of the Fig. Mantel-Haenszel Chi-square for Trend: * p 0.05, ** p 0.01.