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Updated: Aug 17, 2026

Oral Biofilm Sampling for Microbiome Analysis in Healthy Children
Published on: December 31, 2017
Dental caries and microbial acid production in twins
W A Bretz1, P M A Corby, T C Hart
1School of Dental Medicine, University of Pittsburgh, 3501 Terrace Street, Pittsburgh, PA 15261, USA. wab2@pitt.edu
Objective:
To determine the relative contribution of genetic and environmental stimuli on dental caries traits and microbial acid production in a twin model.
Methods:
Dental caries examinations and microbial acid production assays were performed on 388 pairs of twins 1.5-8 years old from the city of Montes Claros, Brazil. Genotyping 8 polymorphic DNA markers determined zygosity. Caries exams followed NIDCR criteria modified to distinguish white spot lesions from cavitated lesions. Surface-based caries prevalence rates (SBCPR) were computed and lesion severity was determined by a weighted index (LSI). Biofilm samples were collected from the tongue using a lactic acid indicator swab. Assay scores were categorized based on acid formation as 1 = low, 2 = medium, and 3 = high. Heritability analyses were performed using the SOLAR software package.
Results:
Heritability estimates for SBCPRs, LSI and for microbial acid production were H = 76.3 (p < 0.001), H = 70.6 (p < 0.001), H = 16.2 (p = 0.0078), respectively. Treating microbial acid production as a covariate in the SBCPR and LSI models did not significantly alter the heritability estimates, i.e. H = 76.5 (p < 0.001) and H = 70.8 (p < 0.001), respectively.
Conclusions:
These results suggest that variation in dental caries surface traits has a significant genetic contribution and that microbial acid production is modulated by the environment.
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