Low basal salivary flow and burning mouth syndrome: new evidence in this enigmatic pathology.

Background: Burning mouth syndrome remains a puzzling condition. One symptom commonly associated with the burning sensation is xerostomia. The current study measured basal and stimulated salivary flow in a group of burning mouth syndrome patients.

Methods: Three groups of patients were recruited: 44 burning mouth syndrome patients, 27 oral lichen planus patients and 40 healthy patients. We chose to measure basal salivary flow and stimulated salivary flow in the three groups of patients using the 'spitting' method. Thus, the patients were asked to spit every minute for 5 min. Afterwards, they were asked to repeat the procedure a second time, but a drop of citric acid was positioned on their tongue every minute to stimulate salivary secretion. After 14 days, the same procedure was repeated for 15 min.

Results: Although there was no significant difference between the burning mouth syndrome group and the other two groups regarding the stimulated volumes, an important difference was found in the basal volumes, with the burning mouth syndrome patients showing lower values.

Conclusions: The outcomes of our research demonstrate the presence of very low basal salivary flow in burning mouth syndrome patients compared with the other two groups, but the stimulated salivary flow was equal, if not higher, in the burning mouth syndrome patients. This study contributes new topics for further investigation of a solution to the very mysterious pathology represented by burning mouth syndrome.