Significantly lower salivary OC concentrations in both healthy and diseased smokers than their non-smoker counterparts were reported by Özçaka et al. (2011b). The detrimental effects of smoking may explain these decreases in salivary levels of OC in smokers also indicating a deficiency in tissue response to the injuries in smoker subjects. The differences in patient numbers and/or the possible differences in the disease activity states may explain the differences in findings of the present study