Virulent Tooth Decay in Toddlers

Early childhood caries, a highly ag­gressive and painful form of tooth decay that frequently occurs in pre­school children, may result from a partnership between a bacterium and a fungus. The resulting tooth decay can be so severe that treatment frequently requires surgery in the operating room. Re­searchers have showed that infection by Streptococcus mutans and Candida albicans together doubled the number of cavities, and boosted their severity several-fold in rats. The bacterium S mutans has long been assumed to be the sole microbial culprit, but researchers noticed that the fungus, C albicans, was almost always present in plaque from cases of early childhood caries. S mutans sticks to the surfaces of teeth by converting sugars to a sticky glue-like material called extracellular polysaccharide (EPS). Candida usually does not associate with S mu­tans, nor does it colonize teeth very effectively. The research­ers discovered that the “exoenzyme” which S mu­tans uses to react with sugar to produce EPS, also enables Candida to produce a glue-like polymer in the presence of sugar, allowing it to adhere to teeth and to bind S mu­tans, 2 abilities it otherwise lacks. Under these circumstances, the fungus now contributes the bulk of the plaque. The combination of the 2 organisms leads to greatly elevated accumulation next to the teeth of the acid that dissolves enamel, leading to cavity formation. This supports the hypothesis that early childhood caries in toddlers results from infection by both organisms, with frequent exposure to sucrose.

(Source: American So­ciety for Mi­crobiology, March 12, 2014)