The main cause of persistent bad breath is are volatile sulphuric compounds. Bacteria in the mouth produce these compounds as a result of bacterial mixing and food debris associated with poor gum and dental hygiene.
The current treatments for halitosis include mechanical cleaning (scaling and tongue scraping) and chemical therapy (antibiotics, mouthwashes and other agents). However, mechanical therapy is often uncomfortable, even if carried out by the dentist. In addition, although chemical therapy is generally effective for a short time, it is always associated with various side effects including the disturbance of normal microbiome of the mouth and staining of the tongue and teeth. Emerging evidence suggests that probiotic bacteria might offer a simpler alternative.
The number of participants in the studies were small, ranging from 23 to 68, with an age range between 19 and 70. Monitoring periods spanned 2 to 12 weeks. Bad breath severity was defined by levels of volatile sulphuric compounds detected in the mouth or the OLP score, which measures breath odour at various distances from the mouth. Tongue coating scores (3 studies) and the plaque index (3 studies) were also included in the analysis because a dirty tongue and the build-up of tartar between the teeth are often regarded as major causes of bad breath.
The pooled data analysis showed that OLP scores fell significantly in those given probiotics compared with those in the comparison study who were not given probiotics, irrespective of the length of the monitoring period.
A similar result was observed for the levels of volatile sulphuric compounds detected, although these varied substantially in the individual studies, and the observed effects were relatively short-livedup to 4 weeks, after which there was no noticeable difference.
But there were no significant differences in tongue coating score or plaque index between those given probiotics and those who weren’t.
Probiotics may inhibit the decomposition of amino acids and proteins by anaerobic bacteria in the mouth, so curbing the production of smelly by-products, the researchers explain.
But they note that one should be cautious of the interpretation of their findings. The sample sizes of the included studies were small and some of the data was incomplete. These factors, on top of differences in detection methods, bacterial species, plus wide variations in the design and methodology of the clinical trials, all weaken the findings.
According to researchers, this systematic review and meta-analysis indicates that probiotics (eg, Lactobacillus salivarius, Lactobacillus reuteri, Streptococcus salivarius and Weissella cibaria) may ease halitosis by reducing the volatile sulphuric compound concentration levels in the short term, but there is no significant effect on the major causes of halitosis, such as plaque and tongue coating.
However, more high-quality randomised clinical trials are required in the future to verify the results and to provide evidence for the efficacy of probiotics in the management of halitosis.
- Efficacy of probiotics in the management of halitosis: a systematic review and meta-analysis – (https:bmjopen.bmj.com/content/bmjopen/12/12/e060753.full.pdf)