Table 1. Demographic data and clinical and periodontal status of the study population including the mean age, the mean time of SLE diagnosis (in years), disease activity (inactive or active), gender distribution, current use of drugs as well as periodontal status and the number of missing teeth are described as the mean ± SD or total number (n) and percentage (%); periodontal parameters (bleeding sites, sites with periodontal pockets, probing depth and clinical attachment level are described as median (p25,p75).

Variable	Control	Periodontitis	SLE	SLE + Periodontitis	p value
	(n = 60)	(n = 51)	(n = 47)	(n = 38)
Age (mean SD)	38.48 (±8.16)	48.96 (±11.30)	33.17 (±8.95)	38.87 (±10.03)	0.110 I
Gender n (%)
Female	47 (78.30%)	29 (56.90%)	43 (91.50%)	36 (94.70%)	<0.001 II
Male	13 (21.70%)	22 (43.10%)	4 (8.50%)	2 (5.30%)
SLE duration (years)	-	-	5.21	10.34	0.001 III
(mean SD)			(5.17)	(7.81)
SLE activity
Inactive SLE n (%)	-	-	20 (42.60%)	24 (63.20%)	<0.001 IV
Active SLE n (%)	-		27 (57.40%)	14 (36.80%)
Medication use
Use of corticosteroid n (%)	-	-	18 (38.30%)	16 (42.10%)	0.086 IV
Use of immunosuppressive n (%)	-	-	30 (63.80%)	17 (44.70%)	0.825 IV
Use of hydroxychloroquine n (%)	-	-	42 (89.40%)	34 (89.50%)	0.987 IV
Periodontal status
Stage II n (%)	-	25 (49.00%)	-	18 (47.40%)	0.877 IV
Stage III or IV n (%)	-	26 (51.00%)	-	20 (52.60%)
Number of missing teeth (mean SD)	-	7.84 (5.84)	8.04 (5.15)	9.16 (4.54)	0.332 I
Bleeding sites (median (p25; p75))	-	41.00 a (24.00; 56.00)	3.00 b (1.00; 8.00)	19.50 c (7.00; 40.00)	<0.001 V
Sites with periodontal pockets (median (p25; p75))	-	25.00 (16.00; 46.00)	-	12.00 (6.00; 23.75)	0.002 VI
Probing depth (median (p25; p75))	-	7.00 (6.00; 8.00)	-	5.50 (5.00; 7.00)	0.032 VI
CAL (mean SD)	-	4.77 (+1.57)	-	5.14 (+1.42)	0.253 III

^IOne-way ANOVA (Tukey post-hoc test);

^IIChi-Square test with Yates Correction;

^IIIStudent T-test;

^IVChi-Square test;

^VKruskal-Wallis test;

^VIMann-Whitney U test. Significance level=5%.