Table 2. The overall microbial community structure comparison using three nonparametric statistical methods.

Groups	MRPP	P-value	ANOSIM	P-value	Adonis	P-value
Among three groupsa	0.351	0.001	0.224	0.001	4.145	0.001
H vs MPa	0.336	0.002	0.301	0.001	4.785	0.001
H vs SPa	0.363	0.001	0.362	0.001	6.160	0.001
MP vs SP	0.352	0.111	0.025	0.216	1.446	0.155

Abbreviations: Adonis, nonparametric multivariate analysis of variance (MANOVA) with the adonis function; ANOSIM, analysis of similarity; H, healthy control; MP, moderate periodontitis; MRPP, multiresponse permutation procedure; SP, severe periodontitis.

^aIndicates significant difference (P<0.05).