[Effect of overdose fluoride on expression of bone sialoprotein in developing dental tissues of rats].
OBJECTIVE
To investigate the changes of bone sialoprotein (BSP) in developing dental tissues of rats exposed to fluoride.


METHODS
Twenty rats were randomly divided into two groups, one was with distilled water (control group), the other was with distilled water treated by fluoride (experimental group). When the fluorosis model was established, the changes of the expression of BSP were investigated and compared between the two groups. HE staining was used to observe the morphology of the cell, and immunohistochemisty assay was used to determine the expression of BSP in rat incisor. Student's t test was used for statistical analysis.


RESULTS
The ameloblasts had normal morphology and arranged orderly. Immunoreactivitis of BSP was present in matured ameloblasts, dentinoblasts, cementoblasts, and the matrix in the control group. But in the experimental group the ameloblasts arranged in multiple layers, the enamel matrix was confused and the expression of BSP was significantly lower than that of the control group. Statistical analysis showed significant differences between the two groups (P<0.01).


CONCLUSIONS
Fluoride can inhibit the expression of BSP in developing dental tissues of rats, and then inhibit differentiation of the tooth epithelial cells and secretion of matrix. This is a probable intracellular mechanism of dental fluorosis.
Xu
Zhi-ling
ZL
Department of Endodontics, School of Stomatology, Tongji University, Shanghai 200072, China.
Wang
Qiang
Q
Liu
Tian-lin
TL
Guo
Li-ying
LY
Jing
Feng-qiu
FQ
Liu
Hui
H