salivary total antioxidant capacity and lipid peroxidation in patients with erosive oral lichen planus

background and aims. oral lichen planus is a common chronic inflammatory disease of the oral mucosa with malignant potential, pathogenesis of which is not still well known. free radicals and reactive oxygen species can play an important role in the pathogenesis of oral lichen planus. the aim of this study was to investigate salivary oxidative stress and antioxidant systems in patients with oral lichen planus. materials and methods. in this case-control study, 30 patients with oral lichen planus (case group) and 30 age- and gender-matched healthy subjects (control group), referring to dental school of babol university of medical sciences, were selected using simple sampling method. unstimulated saliva of the two groups was collected. salivary total antioxidant capacity (tac) and lipid peroxidation products were investigated and compared, using ferric reducing antioxidant power (frap) and thiobarbituric acid reactive substance (tbars) methods, respectively. data were analyzed using student’s t-test. results. the mean and standard deviation of salivary tac in patients with oral lichen planus (297.23 ± 149.72 μm) was significantly lower than that in the controls (791.43±183.95 μm; p < 0.0001), and mean and standard deviation of salivary malondialdehyde (mda) (0.49 ± 0.30 μm) was remarkably higher in oral lichen planus patients compared to the control group (0.15 ± 0.11 μm) (p < 0.0001). tac was also reduced in both groups in line with an increase in the level of mda (p < 0.0001, r = −0.48). conclusion. the results of this study suggested that an increase in oxidative stress and an imbalance in antioxidant defense system in the saliva of oral lichen planus patients may be involved in the pathogenesis of oral lichen planus.