Table 2. Interactions of interacting core taxa.

Specificity to disease groups	Species name	Log2 mRNA/rc-rRNA ratio	Number of samples detected	Species name	Log2 mRNA/rc-rRNA ratio	Number of samples detected	Positive correlation coefficient
Specific to peri-implantitis group	Porphyromonas sp.	6.863	12	Porphyromonas gingivalis	1.098	12	0.740
	Porphyromonas endodontalis	1.238	12	Filifactor alocis	1.207	12	0.643
	Streptococcus sp.	2.489	12	Streptococcus oralis	0.878	11	0.625
	Porphyromonas endodontalis	1.238	12	Eubacterium brachy	4.465	11	0.605
	Selenomonas sputigena	5.428	10	Selenomonas sp.	4.771	12	0.605
	Streptococcus sp.	2.489	12	Selenomonas sputigena	5.428	10	0.601
	Treponema medium	2.409	9	Porphyromonas endodontalis	1.238	12	0.526
	Treponema medium	2.409	9	Fretibacterium fastidiosum	2.154	12	0.496
	Oribacterium sp.	1.361	11	Eubacterium sulci	5.186	11	0.487
	Solobacterium moorei	2.421	9	Eubacterium infirmum	3.113	11	0.483
	Oribacterium sp.	1.361	11	Atopobium rimae	2.072	9	0.479
	Filifactor alocis	1.207	12	Desulfovibrio sp.	2.398	10	0.443
	Neisseria subflava	3.314	11	Corynebacterium durum	0.187	8	0.431
	Prevotella oralis	6.469	11	Atopobium parvulum	2.493	9	0.413
	Streptococcus mutans	1.760	11	Prevotella melaninogenica	2.460	11	0.392
	Selenomonas sputigena	5.428	10	Desulfovibrio sp.	2.398	10	0.375
Specific to periodontitis group	Treponema vincentii	4.598	11	Porphyromonas endodontalis	1.300	11	0.595
	Streptococcus pneumoniae	2.080	10	Gemella haemolysans	0.592	11	0.468
	Gemella morbillorum	1.696	11	Corynebacterium matruchotii	2.583	9	0.430
	Streptococcus sp.	2.615	10	Rothia mucilaginosa	2.928	9	0.384
	Prevotella oralis	7.763	11	Atopobium sp.	6.261	12	0.355