Introduction Nitric oxide (NO) is involved in second messenger formation, osteoblast and osteoclast function, and blood flow. This raises the question of whether or not altered salivary NO levels interfere with tooth loss by influencing the bone remodelling cycle. This study investigates if different levels of salivary NO are associated with existing number of teeth among Korean elderly.

Methods A total of 178 subjects (68 males and 110 females; age range 48–84 years) received a dental and general examination in 2009 and 2010. Number of remaining teeth and salivary flow rate were evaluated by a dentist. Fasting plasma glucose level and blood pressure were also measured. Age, gender, education level, and smoking were evaluated through interview. Salivary NO was determined by the Griess reagent. ANCOVA and Multiple linear regression analyses were applied.

Results After controlling for age, gender, education level, smoking, physical activity, salivary flow rate, fasting plasma glucose level, systolic blood pressure and diastolic blood pressure, higher NO level group showed increased number of teeth compared to moderate and lower NO level group, which is not significant. However, salivary NO levels had a dose-response relationship with the existing number of teeth in Korean elderly (β=−0.007, p=0.046).

Conclusion This study presents for the first time a dose-dependent relationship between salivary NO levels and number of teeth, indicating a link between oral health and salivary NO levels, and that the levels of salivary NO could be a proper indicator for oral health in this respect.