Table 2. Descriptive and clinical characteristics of the examined individuals (all), the study population (Aa-cultivation positive), and the reference group (Aa-negative) at baseline (BL), and at the two-year follow-up (FU) examination.

	Examined individuals
Clinical	BL n = 500		FU n = 397
	n	%	n	%
N individuals (%) with sites AL ≥3 mm	107	21.4	156	39.2
	mean	SD	mean	SD
N of teeth (mean) with AL ≥3 mm	0.52	1.37	1.92	3.34
	Aa -cultivation-positive
	BL n = 200		FU n = 148
	n	%	n	%
N individuals (%) with sites AL ≥3 mm	54	27.0	82	54.4
	mean	SD	mean	SD
N of teeth (mean) with AL ≥3 mm	0.67	1.44	3.01	3.90
	Reference group ( Aa -negative)
	BL n = 228		FU n = 190
	n	%	n	%
N individuals (%) with sites AL ≥3 mm	33	14.4	37	19.4
	mean	SD	mean	SD
N of teeth (mean) with AL ≥3 mm	0.34	1.28	0.89	2.63

AL; attachment loss; BL, at baseline; FU, at two-year follow-up.

Aa; Aggregatibacter actinomycetemcomitans.

SD; standard deviation.