Actinomyces Antibodies as a Marker of Caries Protection by Fluoridated Dentifrices

Objectives: The use of fluoridated dentifrices has led to effective oral hygiene protecting from caries (Sheiham, Int. J. Epidemiol. 13:142, 1984). Effective oral hygiene increases Actinomyces naeslundii colonization in the tooth adherent microbiota (plaque) and elevates actinomyces-specific antibodies (A-Ab) in serum. A means of separating the caries protective effect of fluoridated dentifrices from that of fluoridated drinking water would be useful because fluoride in saliva or enamel poorly predicts caries experience. The aim of this study was to investigate whether clinical measurements, especially caries experience, associate with A-Ab. Methods: DMFT, clinical pocket depth and number of sites that bled on probing or stained for plaque were measured in 67 dental students and 41 patients with known exposure to fluoridated water. Their serum antibodies to purified actinomyces antigen (A-Ab) and to streptococcal D-alanyl lipoteichoic acid (S-Ab) were also measured (Levine et al., J. Clin. Periodontol., 29, 935, 2002). S-Ab indicates exposure to cariogenic bacteria (BMC Oral Health, 2, 2, 2002). Results: Multiple regression analysis indicated that A-Ab concentration decreased with plaque prevalence and DMFT adjusted for Flu, but increased with S-Ab concentration (R² = 0.51, p < 0.002). DMFT covaried with plaque prevalence (R² = 0.14) leaving only a small residual but significant regression (R² = 0.04) with A-Ab. In ANOVA, high A-Ab response (>10.0 µg protein/mL serum) and high Flu reduced mean DMFT by 31.1% and 24.6% respectively: F statistic (A-Ab) = 10.07, p < 0.003; F statistic (Flu) = 4.65, p < 0.02; interactions not significant. Age was a significant DMFT covariate (ANOVA F statistic = 4.83, p < 0.04). Conclusion: A high A-Ab response indicates caries protection independently of water fluoridation, likely due to efficient fluoridated dentifrice use in association with low plaque prevalence. Supported by NIDCR: 1R01 DE-06740.