A Randomized Parallel Study to Assess the Effect of Three Tongue Cleaning Modalities on Oral Malodor

The objective of this study was to compare the effects of three tongue hygiene regimens on oral malodor.

This was a single-center, randomized, parallel design study with three treatment groups. Subjects were randomly assigned to perform tongue hygiene with either the Philips Sonicare TongueCare+ BreathRx regimen (STC), Listerine Cool Mint antiseptic rinse (LCM), or tongue brushing with an ADA reference manual toothbrush (MTB). Tooth brushing was standardized for all subjects during the study period, and no other oral or breath hygiene measures were allowed. Eligible subjects met the following criteria: aged 18-70 years, in good general and oral health, non-smoker, with an organoleptic score between 2.7 and 4.5 following a 12-18 hour oral hygiene abstention period. Subjects who had oral appliances or who had periodontal disease or excessive recession were not eligible. The primary endpoint analysis was to evaluate oral malodor based on an organoleptic (OL) score. Additional surrogate measures for oral malodor included quantification of oral hydrogen sulfide (H2S) level and counts of oral bacteria in secondary analyses. At Day 1, all three malodor endpoints were assessed prior to product use, immediately after use, and four and eight hours after use. Subjects were then provided with instructions on product use at home. Subjects returned to the clinic on Day 8 and the assessments for malodor were repeated for each of the three endpoints, i.e., prior to in-clinic use of the products, immediately after use, and four and eight hours after use.

One hundred sixty-eight (168) subjects were randomized to three groups, with 56 per treatment group. Of these, 165 completed all study visits. Randomized subjects were comparable for baseline characteristics (OL score, age, race, and ethnicity). Overall, oral malodor based on the organoleptic score decreased for all treatment groups at all timepoints. For the primary endpoint, reduction of OL score eight hours following a single product use, the STC regimen reduced malodor per OL score by 46.67% (SE = 2.28%), the LCM value was 22.83% (SE = 2.29%), and MTB was 26.19% (SE = 2.29%). The pair-wise comparisons between STC and each of the treatment groups were statistically significant (p-values < 0.0001). Statistically significant differences were also observed between STC and both LCM and MTB groups in pair-wise comparisons at Day 8 (p-values < 0.0001).

Reductions in malodor were evident following a single use of each product, and also following a seven-day repeat use period. The STC regimen, however, was statistically significantly superior to both LCM and MTB at improving malodor eight hours following the first use. Statistically significant differences in OL scores were sustained between STC and LCM, and STC and MTB at each efficacy timepoint following the seven-day home use period.