Estudo morfológico ultraestrutural e imuno-histoquímico da influência do excesso de flúor no desenvolvimento do germe dental de incisivo de rato / Morphological ultrastructural and immunohistochemical study of the fluorine excess influence on rat incisor tooth germ development

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The dental fluorosis is a result of fluorine toxicity during odontogenesis. Several experimental models have been used in attempt to explain the fluorine pathogenesis in enamel, but during the fetal or the initial postnatal period, there is not much information about its action. For this reason, in this research, the female rats received 0, 7 or 100 ppm of sodium fluoride in drinking water, one week before matching, during all gestation (21 days) and nursing phases. The hemimandibles of the pups at the age of 0, 7 and 14 days of postnatal life (n = 6) were collected for the morphologic study in optical and electronic microscopy, immunohistochemistrical analysis for the amelogenin and morphometric study of the enamel matrix and of ameloblasts in the secretion and maturation phases of the lower incisive. The results showed a reduction of the enamel matrix secretion, disorganization of the mitochondrial crests, large vacuoles in the apical portion of the cytoplasm, retention of the intracisternal material and dilatation of some cisterns in rough endoplasmic reticulum for the secretory ameloblasts of 100 ppm experimental group in all experimental periods. In the groups of animals at the age of 7 and 14 days, a reduction (p<0.05) in the cytoplasmic volume of 23.80% and 24.75%, respectively, was observed in relation to the control groups. In smoothed-border maturation ameloblasts, there was a great amount of vacuoles with endocited electrondense matrix, suggesting a retard in the reabsorption process. In ruffled-border ameloblasts, there were some dilated mitochondrias. The immunohistochemistrical analysis showed no difference in intensity and marking pattern of the enamel matrix in any of the studied groups. Therefore, part of the excessive dose of sodium fluoride given to the mother in drinking water can reach the pup by the placenta and by the mothers milk, causing morphological alterations in ameloblasts and suggesting a reduction in the secretion and a retard in the matrix reabsorption.

ASSUNTO(S)

incisivo flúor (influências) germe de dente (desenvolvimento)

Documentos Relacionados