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Acidogenicity and acid tolerance of Streptococcus oralis and Streptococcus mitis isolated from plaque of healthy and incipient caries teeth
Journal article   Open access   Peer reviewed

Acidogenicity and acid tolerance of Streptococcus oralis and Streptococcus mitis isolated from plaque of healthy and incipient caries teeth

Jeffrey A Banas, Min Zhu, Deborah V Dawson, Derek R Blanchette, David R Drake, Hongjie Gu, Ryan Frost, Grant McCaulley and Steven M Levy
Journal of Oral Microbiology, Vol.8(1), 32940
01/01/2016
DOI: 10.3402/jom.v8.32940
PMCID: PMC5084378
PMID: 27790973
url
https://doi.org/10.3402/jom.v8.32940View
Published (Version of record) Open Access

Abstract

Non-mutans low pH oral streptococci are postulated to contribute to caries etiology. This study was undertaken to investigate whether the acidogenicity and acid tolerance of clinical strains of Streptococcus oralis and Streptococcus mitis correlate with health or early-stage enamel caries. S. oralis and S. mitis were isolated from plaque samples taken from the occlusal surfaces of second molars sampled at two different visits 4 years apart. All sites were sound at Visit 1; subjects were segregated into one of three groups based on the status of the site at Visit 2 and caries elsewhere in the dentition. Strains of S. oralis and S. mitis were evaluated for acidogenicity and acid tolerance, and the results correlated with the clinical status of the sites from which they were isolated. Mutans streptococci (MS) isolated from the plaque samples were also quantified, and the presence or absence of growth on pH 5.5 media or on media selective for bifidobacteria was recorded. No significant positive correlations were found between the acidogenicity properties of the S. oralis and S. mitis clones and caries at either visit. Similar results were obtained for acid tolerance of S. oralis clones but were inconclusive for S. mitis clones. A statistically significant positive correlation between MS levels and caries (or future caries) was evident at both visits, but there were no statistical correlations with the growth on pH 5.5 media or media selective for bifidobacteria. The low pH potential likely varies considerably among oral streptococcal species and is least likely to be found among strains of S. mitis. Accordingly, the concept and constitution of 'low pH streptococci' may need to be re-evaluated.
dental plaque acid tolerance mutans streptococci oral microbiota acidogenicity cariogenicity

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