Rapid Griess assay (RGA): a chairside test for semi-quantitative oral nitrite measurement and assessment of nitrite production by oral bacteria.

BACKGROUND

Nitrite (NO ) is produced through enzymatic reduction of dietary nitrate (NO ) by oral bacteria: a process contributing to cardiovascular - and possibly oral - health. NO 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 in oral samples. We also evaluated NO generation in several bacterial species .

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 production.

RESULTS

In saliva, plaque and tongue samples, low, variable and high NO levels, respectively, were found. Tongue samples were the most stable over time. High and medium NO production capacities were shown by spp. (including ), and spp. RGA results were reproducible.

CONCLUSION

The RGA provided stable and reliable results for chairside NO semi-quantitation, and revealed elevated and stable NO levels on the tongue. , bacterial NO production was consistent with the available literature, but uncertainty remains regarding spp. Our results showed promise for clinical and research applications of the RGA.