Probiotics for caries prevention?


Caries is the most common chronic disease in children and adults and it is costly to manage. Studies have suggested that probiotic bacteria may have a beneficial effect on caries prevalence.

The aim of this study was to evaluate the effect of a probiotic chewing tablet, given as a daily supplement after fluoride toothpaste use, on the development of early childhood caries in preschool children living in a multicultural low-socioeconomic area.


Healthy Children age 2-3 years of age were randomised to receive either probiotic chewing tablets containing not less than a 1 × 108 total CFU ProBiora3® blend of three strains of probiotic bacteria (S. uberis KJ2TM, S. oralis KJ3TM, S. rattus JH145TM) or placebo tablet. The tablets had a wild cherry flavour and were sweetened with erythritol, a natural low-cariogenic polylol.   Compliance was rated as ‘acceptable’ when ≤3 tablets per week were forgotten and as “questionable” when this happened more frequently.

All parents were thoroughly instructed to carry out tooth brushing with a smear layer of fluoridated toothpaste (1,100 ppm) twice a day (morning and evening) throughout the entire study period. Children were clinically examined at baseline and after 1 year by one of two trained and calibrated dental hygienists.

Caries was visually scored on surface level as, sound (no evidence of caries), initial (first visual change in enamel), cavitated (breakdown of enamel, with or without visible dentine) or arrested (hard and smooth surface but whitish, brownish or black) after drying and cleaning and expressed as decayed surfaces (ds). Caries increment was calculated for each patient.


  • 138 patients were randomised (71 intervention, 67 placebo)
  • 28 patients (20%) were lost to follow up, 17 in intervention group 11 in placebo group.
  • Compliance was graded as acceptable in 72 % of the children in the test group and 69 % in the placebo group.
  • Mean caries increment (ds) at 1 year was significantly lower in the  in test group =0.2 (SD, 1.2)  placebo group = 0.18 ( SD, 1.4)
    • Absolute risk reduction = 22%
    • Relative risk reduction = 0.47 (95% CI; 0.24–0.98)
    • Numbers needed to treat = 5
  • No adverse effects were reported.


The authors concluded:

Within the limitations of the present study, the results suggested that early childhood caries development could be reduced through daily administration of these probiotic chewing tablets as adjunct to daily use of fluoride toothpaste in preschool children. Therefore, further studies to confirm these findings and clarify a possible dose–response relationship, as well as health economic issues, seems justified.


This is an interesting trial that suggests that probiotics may be helpful in reducing caries. However as the authors’ note other studies conducted in a range of age groups provide conflicting results. The authors also highlight the challenges they faced in recruitment and the high level of drop out (20%) should be noted. Both recruitment to the study, drop out and compliance could have been related to the potentially challenging treatment regime of a daily pill for children. Additional studies need to be carried out to see if these findings are repeatable if there is a dose-response and the whether the intervention is acceptable and cost effective.

Previously we looked at a systematic review ( Dental Elf 28th April) which suggested that probiotics reduced mutans streptococci counts. While that review included 19 studies only 2 reported caries as an outcome.


Primary paper

Hedayati-Hajikand T, Lundberg U, Eldh C, Twetman S. Effect of probiotic chewing tablets on early childhood caries-a randomized controlled trial. BMC Oral Health. 2015 Sep 24;15(1):112. doi: 10.1186/s12903-015-0096-5. PubMed PMID: 26403472; PubMed Central PMCID: PMC4583156.

Other references

Original trial protocol

Dental Elf -28th Apr 2014 – Insufficient evidence that probiotics can prevent caries, but they can reduce the mutans streptococci counts in the short term

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Derek Richards

Derek Richards is a specialist in dental public health, Director of the Centre for Evidence-Based Dentistry and Specialist Advisor to the Scottish Dental Clinical Effectiveness Programme (SDCEP) Development Team. A former editor of the Evidence-Based Dentistry Journal and chief blogger for the Dental Elf website until December 2023. Derek has been involved with a wide range of evidence-based initiatives both nationally and internationally since 1994. Derek retired from the NHS in 2019 remaining as a part-time senior lecturer at Dundee Dental School until the end of 2023.

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