Abstract
BACKGROUND: Nitrite (NO(2) (-)) is produced through enzymatic reduction of dietary nitrate (NO(3) (-)) by oral bacteria: a process contributing to cardiovascular - and possibly oral - health. NO(2) (-) quantitation in biological samples is a complex exercise, and available methods are not well-adapted for chairside use. Therefore, we aimed to develop and evaluate a semi-quantitative chairside test for NO(2) (-) in oral samples. We also evaluated NO(2) (-) generation in several bacterial species in vitro. MATERIALS AND METHODS: From 12 healthy individuals, tongue, saliva and plaque samples were collected and evaluated chairside across 4 weeks, using the rapid Griess assay (RGA). The RGA was further used to test bacterial species for NO(2) (-) production. RESULTS: In saliva, plaque and tongue samples, low, variable and high NO(2) (-) levels, respectively, were found. Tongue samples were the most stable over time. High and medium NO(2) (-) production capacities were shown by Actinomyces spp. (including Schaalia odontolytica), Veillonella parvula, and Rothia spp. RGA results were reproducible. CONCLUSION: The RGA provided stable and reliable results for chairside NO(2) (-) semi-quantitation, and revealed elevated and stable NO(2) (-) levels on the tongue. In vitro, bacterial NO(2) (-) production was consistent with the available literature, but uncertainty remains regarding Neisseria spp. Our results showed promise for clinical and research applications of the RGA.