Clinical effectiveness of essential oil-containing dentifrices in controlling oral malodor

To assess the efficacy of two essential oil-containing dentifrices in the reduction of human intrinsic oral malodor ("morning bad breath").

Two clinical trials were conducted which used observer-blind, negative control, parallel designs. To insure a homogeneous test population with similar oral odor characteristics, subjects followed instructions that included toothbrushing with a standard ADA-accepted fluoride dentifrice the night before. On odor evaluation days, subjects refrained from all oral hygiene procedures and from eating or drinking any food or beverage or smoking prior to and during the odor evaluations. Eighty healthy adult subjects in the first trial and 90 in the second trial with qualifying baseline levels of oral malodor participated. Odor ratings of each subject's breath were made by 4-5 trained judges using a nine point hedonic scale, i.e., 1 = most pleasant, 5 = neutral, 9 = most unpleasant. Qualifying subjects were randomly assigned one of two essential oil dentifrices or a negative control dentifrice. Subjects brushed with their assigned dentifrice for 60 s, rinsed with 20 ml of water for 10 s, and received post-treatment hedonic odor ratings at 30, 60, 90, 120, 180, and 240 min. Data were analyzed using an ANCOVA to adjust for baseline scores.

The essential oil dentifrices were significantly more effective (P < or = 0.033) than the control in reducing intrinsic oral malodor from 90 to 120 min.