The microbial etiology of dental caries continues to be researched and debated. While S. mutans is recognized as a prominent cariogenic species, caries - even severe caries - have been observed in the absence of detectable levels of S. mutans. It has been postulated that certain strains among primary plaque- colonizing species of streptococci may represent an alternative etiology of dental decay. These strains have been designated low-pH, non-mutans-streptococci (non-MS) variants. They are significantly more acidogenic and aciduric than is typical for their species and rival the acid-related properties of . mutans. Data from a handful of cross-sectional studies supports the hypothesized role for the low-pH, non-MS in caries etiology. In this application we propose to further test the hypothesis that low-pH, non-MS strains have a potential role in caries etiology by taking advantage of an ongoing study, the Iowa Fluoride Study, that has collected and banked site-specific samples from the occlusal surfaces of second molars from subjects enrolled long-term within the study. In particular, we have samples from identical sites within subjects at ages 13 and 17. Some of these sites show incipient decay (white-spot lesions) at age 17 after being clinically sound at age 13. We propose to: 1) Isolate non-MS strains of primary colonizing streptococci from second molar occulsal samples, determine the diversity of genotypes present, and the diversity of acid-related phenotypes for those strains;and 2) Correlate the acid-related phenotypes with the site-specific caries experience of the subjects from whom they were isolated. The study design will allow longitudinal and cross-sectional data analyses that represent a unique approach to testing this important hypothesis.

Public Health Relevance

This application proposes to investigate whether dental caries may be caused by the presence of unique low-pH variants of streptococcal species that commonly colonize teeth and contribute to plaque formation. We will isolate strains from site-specific samples collected at different ages and correlate the acid properties of those strains with the clinical status of the sites from which they were isolated.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21DE022605-01
Application #
8278764
Study Section
Special Emphasis Panel (ZRG1-MOSS-S (03))
Program Officer
Lunsford, Dwayne
Project Start
2012-04-01
Project End
2014-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
1
Fiscal Year
2012
Total Cost
$188,750
Indirect Cost
$63,750
Name
University of Iowa
Department
Dentistry
Type
Schools of Dentistry
DUNS #
062761671
City
Iowa City
State
IA
Country
United States
Zip Code
52242
Banas, Jeffrey A; Popp, Eric T (2013) Recovery of Viable Bacteria from Probiotic Products that Target Oral Health. Probiotics Antimicrob Proteins 5:227-231