The use of probiotics for a wide range of conditions has been promoted and a potential caries protective effect has also been postulated. The aim of this review was to assess the caries preventive effect of probiotics in humans.

The Medline and Embase databases were searched for randomised controlled trials assessing the in vivo role of probiotics administration on caries lesion development and on caries risk factors control. Only English language studies were included. Two reviewers carried out study selection independently with disagreements being resolved by discussion.  Study quality was assessed by scoring against the 2010 CONSORT checklist, with studies with ≥20 items being deemed excellent, those with 13 and 19 items good and those with ≤12 items rated as poor. A qualitative synthesis was presented.

• 23 papers were included, 4 were rated as excellent, 9 good and 10 poor.
• Only three studies had caries as an outcome the remainder used surrogate end points.
• Study duration varied from 10 days to 23 months with the majority (80%) being between 10-42 days.
• A majority of studies showed significant reductions in some relevant bacterial species.

The authors concluded

The use of probiotic strains for caries prevention showed promising results even if only few studies have demonstrated clear clinical outcomes. Therefore, the scientific evidence is still poor.

Comment

As only two databases and English language papers were included there is a strong possibility that not all studies have been included in this review.  The variety of probiotics and different vehicles used (milk, ice cream, cheese, chewing gum, yoghurt) presents a challenge for analysis. A majority of the studies looked at the effect of probiotics on bacterial species associated with caries, however many of these studies were small and of short duration.   The authors used the CONSORT checklist as a score sheet to rank the studies and while the CONSORT checklist provides a useful indication of items that should be reported in a trial not all the items are of equal importance. Consequently the risk of bias tools adopted by the Cochrane Collaboration would be more appropriate to assess quality. As the authors note the main aim of the use of probiotics is to replace or displace cariogenic bacteria and while some of the studies did show an effect in some cases this was short term only and re-colonisation occurred.  In addition the majority of the studies looked only at microbiological outcomes and there may be no effect on caries.

Links

Cagetti MG, Mastroberardino S, Milia E, Cocco F, Lingström P, Campus G. The use of probiotic strains in caries prevention: a systematic review. Nutrients. 2013 Jul 5;5(7):2530-50. doi: 10.3390/nu5072530. PubMed PMID: 23857225; PubMed Central PMCID: PMC3738986.