Both tongue brushing and oral probiotics were effective in reducing halitosis, with the combined intervention producing the most significant and sustained improvements.
Key Findings
Results
VSC levels were significantly decreased after 4-week intervention in the oral probiotics, tongue brushing, and combined groups.
All three active treatment groups showed statistically significant reductions in volatile sulfur compound (VSC) levels (all p < 0.05).
The greatest reduction in VSC levels was observed in the combined tongue brushing and oral probiotics group.
The control group was not reported to show significant VSC reduction.
Assessments were taken at baseline, after 4-week intervention, and at a 4-week intervention-free follow-up.
Results
The combined group's VSC levels remained significantly lower than baseline at the 4-week intervention-free follow-up despite slight rebounds.
The combined group showed sustained VSC reduction even after the intervention period ended.
VSC levels showed 'slight rebounds' during the follow-up period in the combined group.
The sustained effect was specific to the combined tongue brushing and oral probiotics group.
This finding suggests the combination approach produces more durable effects than either intervention alone.
Results
Self-reported halitosis scores decreased after both the intervention period and the follow-up period.
Self-reported halitosis scores decreased after intervention and follow-up (p < 0.05).
The improvement in self-reported halitosis was sustained through the 4-week intervention-free follow-up.
The specific groups showing this reduction were not individually specified in the abstract.
Results
Organoleptic scores improved only in the combined tongue brushing and oral probiotics group post-intervention.
Organoleptic score improvement was statistically significant in the combined group (p < 0.01).
Neither the oral probiotics group alone nor the tongue brushing group alone showed significant organoleptic score improvement.
The control group did not show organoleptic improvement.
Organoleptic scoring is a sensory assessment of breath odor by a trained evaluator.
Results
Tongue coating scores decreased in both the tongue brushing and combined groups, but not in the oral probiotics group.
Tongue brushing alone was effective in reducing tongue coating index scores.
The combined group also showed reduction in tongue coating scores.
Oral probiotics alone did not significantly reduce tongue coating scores.
The control group was not reported to show significant tongue coating reduction.
This suggests the mechanism of action for oral probiotics does not primarily involve reduction of tongue coating.
Methods
The study enrolled 80 participants randomized into four equal groups across a prospective, randomized, placebo-controlled trial design.
Participants were allocated to: control (n = 20), oral probiotics (n = 20), tongue brushing (n = 20), and combined tongue brushing and oral probiotics (n = 20).
The oral probiotic used was Streptococcus salivarius K12.
The study design was prospective and randomized with a placebo control.
Three assessment time points were used: baseline, after 4-week intervention, and after 4-week intervention-free follow-up.
Outcome measurements included VSC, self-reported halitosis, organoleptic score, and tongue coating index.
Mei L, Yan F, Cheng L, Na A, Cannon R, Guan G. (2026). Tongue brushing and oral probiotics for the treatment of halitosis: a randomized controlled trial.. Journal of breath research. https://doi.org/10.1088/1752-7163/ae3edc