> Developmental dental toxicity of dioxin and related compounds ...
The effect of perinatal TCDD exposure on caries susceptibility in
rats.
TCDD, the model compound of polychlorinated dibenzo-p-dioxins and
furans, is a potent toxicant with the ability to hamper development.
Accidental exposure to TCDD has been linked with various developmental
dental aberrations in humans, and experimentally it has been shown
that TCDD causes, among other defects, hypomineralization of dental
hard tissues in rodents. Here, we studied the effect of very low
perinatal TCDD exposure on dental caries susceptibility and mineral
composition of tooth enamel in rats. Pregnant line C rats (rat line
developed in our laboratory) were dosed 0.03-1.0 microg/kg TCDD on
gestation day 15 and allowed to give birth and nurse until weaning on
postnatal day 21. The offspring were challenged with cariogenic
treatment including sugar-rich diet and three inoculations with
Streptococcus mutans. Control groups involved animals with or without
cariogenic challenge or TCDD treatment. The number of caries lesions
in left lower molars was determined by Schiff's staining after 8 weeks
of weaning. TCDD treatment increased cariogenic lesions in the enamel
at the lowest maternal dose used, 0.03 microg/kg, and at the highest
maternal dose, 1 microg/kg, the lesions extended through the enamel to
dentin more frequently. Changes in mineral composition measured by
electron probe microanalyzer, scanning electron microscopy, and energy-
dispersive spectrometry could not explain the increased caries
susceptibility. In conclusion, perinatal TCDD exposure can render rat
molars more susceptible to caries. PMID: 16543294
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