Probiotics for dental health?
Reviewed by Zijnge V.
Probiotics are known for their beneficial effect on the gut flora. The application of probiotics to fight microbial related diseases in the oral cavity has gained not much attention. In the oral cavity, caries, periodontitis and halitosis are the main causes for dental treatment.
Caries is the result of acids produced by anaerobic degradation of sugars by bacteria. The genus Streptococcus is known for its cariogenic activity, especially Streptococcus mutans. In a Swiss study Streptococcus thermophilus NC1561 en Lactobacillus lactis NCC2211 were succesfully incorporated in a biofilm. This biofilm mimicked the biofilm on the teeth. L. lactis was able to diminish the colonization of the cariogenic bacteria Streptococcus oralis OMZ607 and Streptococcus sobrinus OMZ176. These results may stimulate further research in replacement of cariogenic bacteria by non-cariogenic dairy bacteria in dental plaque.
Periodontal diseases are characterized by inflammation of the gingiva and accompanied with the loss of supportive bone. The primary aetiologic factor is the bacterial biofilm. The biofilm is dominated by Gram-negative anaerobic rods. Porphyromonas gingivalis, Tannerella forsythensis en Treponema denticola are highly associated with periodontitis. Interestingly, little effort has been put into the field of replacement therapy in periodontal disease, despite the large medical and economical pressure of periodontal diseases on society.
Halitosis is known as oral maladour and may afflict up to half of the human population. Bad breath is caused by bacterial metabolic products. The most common products are volatile sulphur compounds, short-chain-fatty-acids and putrescine and cadaverine. These compounds are produced by bacteria located on the dorsum of the tongue like Porphyromonas gingivalis, Prevotella intermedia or Fusobacterium nucleatum, although the population is highly diverse. Recently, Streptococcus salivarius K12 has been tested as a probiotic. Twenty-three subjects with halitosis were treated with chlorhexidine during three days. Thirteen subjects received lozenges containing S. salivarius K12 at 2-hour intervals during 8 hours. Eleven subjects received a placebo. On day 2 and 3 subjects brushed their teeth and rinsed with chlorhexidin, followed by taking lozenges as on day 1 for the active group. Subsequently they took a lozenge every morning and evening after normal oral care for two weeks. After 1 week 85% of the K12-group and 30% of the placebo group showed a decrease ( >100 bbp) in volatile sulphur compounds.
Oral probiotics are a new field in probiotics and the exploration of their therapeutic potential has just started. Main issues are the establishment of probiotics in the oral cavity, the long- lasting effects and the possibility that probiotics can have both beneficial and adverse effects. For example, the introduction of streptococci for the treatment of halitosis may introduce a high number of cariogenic species. Finally, double-blind, randomized, placebo-controlled studies are needed to scientifically support the use of oral probiotics.