Microbiology and treatment of oral malodor.

Abstract

There is little knowledge of the composition of the tongue flora in health and disease. Its role in the pathogenesis of oral infections is poorly studied, although it has been implicated as a major site of odor production in patients with chronic halitosis. The anaerobic microflora contributes to the halitosis, yet it remains to be determined which species are responsible. Cultural studies of the dorsal surface of the tongue indicate that we can recover only 52% of the microscopic bacterial count from surface coatings. Of that 52%, only 40% are identifiable using standard biochemical assays. The growth media yielding the highest cultivable percent recovery of organisms contained human blood and saliva. The most commonly isolated bacterial species in health included <italic>V. parvula, S. intermedius, A. odontolyticus</italic> and <italic>C. innocuum</italic>. Using molecular phylogeny, we identified 92 different bacterial species in samples from both healthy and malodor subjects. Approximately half of these species were phylotypes, of which 25 were novel to the tongue microbiota. Those species associated with health were <italic>Streptococcus salivarius, Rothia mucilaginosa</italic>, and an uncharacterized species of <italic>Eubacterium </italic>. Those associated with halitosis were <italic>Atopobium parvulum </italic>, an uncharacterized species of <italic>Dialister, Eubacterium sulci, </italic> an uncultivated phylum TM7 phylotype, <italic>Bulleidia moorei</italic>, and a <italic>Streptococcus</italic> phylotype. Using over 100 species-specific 16S rRNA oligonucleotide probes in a checkerboard DNA-DNA hybridization assay, those tongue species encountered in health included <italic>Streptococcus salivarius</italic>, a <italic>Eubacterium </italic> sp., an<italic> Actinomyces</italic> sp., and <italic>Rothia mucilaginosa </italic>. Those encountered in malodor patients included <italic>Eubacterium sulci</italic>, a phylotype of <italic>Prevotella</italic>, a phylotype of <italic> Porphyromonas</italic>, <italic>Veillonella atypica</italic>, and several <italic> Fusobacterium</italic> species. In treated malodor patients after one year, the levels of halitosis-related species were reduced and levels of health-related species were increased, suggesting a specific microbiota associated with malodor. We have developed a treatment regimen that improves subjective and objective measurements of halitosis in 100% of treated individuals for up to 2 years. This is unprecedented compared to reports in the literature, which describe efficacy of up to 12 hours.