Use of essential oil-containing mouthrinses by xerostomic individuals: Determination of potential for oral mucosal irritation

Purpose: To assess the irritation potential of an essential oil-containing mouthrinse (Listerine Antiseptic) in a population with objectively documented xerostomia (hyposalivation) using an exaggerated-exposure clinical model. Methods: Following a baseline oral soft tissue examination, 19 qualifying female subjects with a mean age of 61 years and a mean unstimulated baseline salivary flow of 0.06 mL/min were randomly assigned either the essential oil mouthrinse or a negative control rinse. They rinsed under supervision with 20 ml of their assigned rinse for 30 seconds and 5 minutes later a second salivary flow rate was determined. They then rinsed unsupervised with 20 ml for 30 seconds three times daily for the next 14 days, and received soft tissue examinations on days 7 and 14. After a 1-week interim period, subjects switched to the alternate rinse and the examination and rinsing regimens were repeated during the subsequent 2 weeks. Results: The oral irritation potential of the essential oil mouthrinse was minimal. Oral mucosal abnormalities attributable to the test rinses were seen in only 2 subjects, both at the 7-day examination. These subjects were both using the essential oil mouthrinse. The abnormalities consisted of an asymptomatic "whitish slough" which was readily wiped off leaving a normal appearing, non-erythematous mucosa. In both subjects, the oral mucosa appeared normal at the 14-day examination.