Exposure to lead exacerbates dental fluorosis.
OBJECTIVE
Our aim was to test the hypothesis that co-exposure to lead and fluoride alter the severity of enamel fluorosis.


METHODS
Wistar rats were allocated in four groups: control, and 3 groups that received water containing 100 ppm of fluoride (F), 30 ppm of lead (Pb), or 100 ppm of F and 30 ppm of Pb (F+Pb) from the beginning of gestation. Enamel analysis and F and Pb determinations in enamel, dentine, and bone were performed in 81-day-old animals. Fluorosis was quantified using a new fluorosis index based on the identification of incisor enamel defects (white bands and white islets, representing hypomineralization, and cavities) weighted according to their severity and quantity. Hypomineralization was validated histopathologically by polarizing microscopy and microradiography. Scores were given by two blinded calibrated examiners (intra and interexaminer kappa values were 0.8 and 0.86, respectively).


RESULTS
The control and the Pb groups presented normal enamel. The F+Pb group presented more severe enamel defects compared with the F group (P<0.0001).


CONCLUSIONS
This study shows that lead exacerbates dental fluorosis in rodents, suggesting that co-exposure to lead may affect the degree of fluorosis.
Department of Morphology, Stomatology and Physiology, School of Dentistry of Ribeirao Preto, University of Sao Paulo (FORP/USP), Avenida do Café, S/N, 14040-904 Ribeirao Preto, SP, Brazil.
G A S
GA
Leite
R M M
RM
Sawan
J M
JM
Teófilo
I M
IM
Porto
F B
FB
Sousa
R F
RF
Gerlach
D000818:Animals; D002327:Cariostatic Agents / Q000009:adverse effects* / Q000032:analysis; D003731:Dental Caries / Q000139:chemically induced / Q000473:pathology; D003743:Dental Enamel / Q000737:chemistry; D003804:Dentin / Q000737:chemistry; D004357:Drug Synergism; D004781:Environmental Exposure; D005260:Female; D005269:Femur / Q000737:chemistry; D005459:Fluorides / Q000009:adverse effects* / Q000032:analysis; D009050:Fluorosis, Dental / Q000145:classification / Q000209:etiology* / Q000473:pathology; D007180:Incisor / Q000737:chemistry; D007854:Lead / Q000009:adverse effects* / Q000032:analysis / Q000097:blood; D008297:Male; D008852:Microradiography; D008859:Microscopy, Polarization; D010758:Phosphorus / Q000032:analysis; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D014074:Tooth Calcification / Q000187:drug effects; D017001:Tooth Demineralization / Q000139:chemically induced / Q000145:classification / Q000473:pathology; D014881:Water Supply / Q000032:analysis
D002327:Cariostatic Agents; D010758:Phosphorus; D007854:Lead; D005459:Fluorides