Probiotics and dental caries
Probiotic bacteria have long been a part of the diet in many countries. The most frequently used strains are from bifidobacteria and lactobacilli, but also some streptococcus strains have been used in experiments, and can be found in some products.
The most common forms of administration are chewing tablets or milk (either plain milk or powdered milk), but several other vehicles, such as yogurt, kefir, ice cream, cheese, porridge and drops have also been used. Different mechanisms of action are believed to be involved in the effect of probiotic bacteria on caries. These may be divided into a local effect and systemic effect.
Two systematic reviews have concluded that there is evidence that a regular intake of probiotic bacteria can reduce the proportion of mutans streptococci in saliva and suggest that probiotics thereby may be beneficial in caries prevention.
The clinical studies on caries are published from 2001 and upward, but the majority is published within the last 3 years. The preventive effects in clinical studies claim to vary between 5% and 75% This wide range may be caused by highly varying design, bacterial strain, intervention period and number of participants. In these studies, the effect on caries is measured immediately after an intervention period of varying length, but some recent studies also follows up the effect of an intervention period several years earlier. These studies with long follow-up are interesting because they suggest that it is possible to achieve an effect with early intervention.