BACKGROUND: Both chronic plaque psoriasis and periodontitis have an increasing prevalence worldwide and have been associated with the metabolic syndrome; however limited information is available on their association.OBJECTIVE: To evaluate the possible association of severe periodontitis and chronic plaque psoriasis.METHODS: This was a hospital based case-control study. Chronic plaque psoriasis patients and age- and gender-matched controls have been recruited. Baseline demographic data have been recorded. To explore correlations between different dichotomous variables the Sperman Rho correlation coefficient was used. Correlations were further explored non-parametrically and univariate and multivariate logistic regression was utilized after adjustment for the effect of confounders.RESULTS: During the study enrollment period 100 patients with CPP and 100 age- and gender-matched controls were included in this study. Mean age for both groups was 57.2 ± 5.3 years. 43% of patients and controls were males. Significant correlations where noted between psoriasis and 1) periodontitis (rho = 0.219, P = 0.02) and 2) metabolic syndrome (rho = 0.191, P = 0.07) using Spearman's Rho correlation co-efficient. Univariate logistic regression reported significant relations between psoriasis and periodontitis (OR = 3.329, 95%CI: 1.513-7.324, P = 0.003) and psoriasis and metabolic syndrome (OR = 2.293, 95%CI: 1.250-4.207, P = 0.007). On the contrary, a non-significant relation between psoriasis and active smoking status was detected (OR = 1.041, 95%CI: 0.597-1.817, P = 0.887). In a multivariate analysis model we found a significant correlation of psoriasis and periodontitis when controlled for the presence of metabolic syndrome (OR: 2.486, 95%CI: 1.002-5.842, P = 0.049).CONCLUSION: Periodontitis may be associated with psoriasis but further studies are required to elucidate their relationship in the context of the biologic plausibility.