Probiotic suppresses periodontitis bacterium

Jun 22, 2009

A probiotic tablet containing a strain of Lactobacillus salivarius suppressed at least one of the bacteria responsible for periodontitis in a randomized controlled study, according to researchers from Wakamoto Pharmaceutical, which markets the tablets.

The researchers had previously found the tablets to improve clinical parameters of periodontitis in smokers. In a study published this year in the Journal of Clinical Periodontology (JCP, June 2009, Vol. 36:6, pp. 506-513), the researchers studied the tablets' effects on Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia.

They gave 34 healthy volunteers 2.01 x 10⁹ colony-forming units of L. salivarius WB21 per day in a tablet containing xylitol. Another 32 healthy volunteers took a placebo with xylitol. After 4 weeks, the researchers found reduction in the total number of the subgingival periodontitis-related bacteria in the test group. The reduction was significantly greater in the test group than in the placebo group.

After adjusting for bacterial counts at base line, smoking status, and plaque index, only the reduction of T. forsythia was statistically significant.

L. salivarius may suppress other bacteria by producing lactic acid and other hydrogen peroxide metabolites, the researchers theorized. Too much lactic acid could dissolve tooth enamel, the researchers acknowledged, but they saw no sign of this problem after 8 weeks of observation.

In a previous study published last year (JCP, October 2008, Vol. 35:10, pp. 897-905), the researchers reported that all the patient groups who took the tablets improved clinical parameters of periodontitis. But the improvement wasn't statistically significant compared to a placebo group, except in probing pocket depth, gingival index, and plaque index for smokers.