evaluation of salivary nitric oxide level in children with early childhood caries

background: nitric oxide (no), a highly reactive radical, participates in the nonspecific natural defense mechanism of the oral cavity. aims and objectives: the present study was attempted to evaluate the salivary no levels in 4–5 year‑old children with early childhood caries (ecc). the objective of the present study was to assess the salivary no concentration in children with different caries activity. materials and methods: the study included 120 healthy 4–5 year‑old children and they were equally divided into three groups based on decayed, missing, filled surfaces (dmfs) score; forty caries‑free children (control group), forty children with dmfs 1–5 (ecc group), and forty with dmfs ≥6 (severe ecc group). saliva collected was measured for no concentration by griess reaction method. the obtained data were analyzed by anova and pearson’s correlation coefficient. results: the mean level of no in the saliva of the control group was 51.2 ± 8.3457 and that of ecc and severe ecc were 47.1 ± 5.2614 and 33.625 ± 4.6942, respectively. the mean salivary no concentration was significantly higher in healthy controls when compared to children with ecc and severe ecc. moreover, a negative correlation ( r = −0.6658) was observed between the salivary no level and the mean dmfs, suggesting that as the salivary no level decreases, the caries incidence increases. conclusion: the obtained results support the antimicrobial activity of salivary no and also suggest that an increase in no production might contribute to lower the caries occurrence in children. key words: dental caries, nitric oxide, saliva