Ameloblast morphology and ultrastructure changes of dental fluorosis in rats / 中华地方病学杂志

ABSTRACT

Objective To observe the ameloblast morphology and ultrastructure changes of dental fluorosis in rats.Methods Forty SD rats were divided into experimental group and control group (20 rats in each group) by body weight using random number table method.Rats in experimental group were given drinking water with 50 mg/L fluoride to establish dental fluorosis model,and rats in control group were given drinking water without fluoride.All rats were killed at the 56th day,then ameloblast morphology and ultrastructure were observed by means of HE staining and transmission electron microscopy (TEM) at secretory,transition,maturation and post-maturation stages.Results Rats in experimental group showed typical symptoms of dental fluorosis,and lower incisors presented brown and white stripes on enamel surface,chalk color patches and other typical dental fluorosis changes,rats in control group no abnormality.HE staining results showed that differences were not observed between the two groups at the secretory and transformation stages,and few distortions and interstitial space widened were found in the experimental group at maturation and post-maturation stages.TEM displayed ultrastructure changes of ameloblasts,and no differences were observed between the two groups at secretory and transformation stages.Apoptosis was observed in some ameloblasts at the maturation stage in the experimental group,such as rough endoplasmic reticulum expansion,swelling,some ribosome particles exfoliating from endoplasmic reticulum,mitochondrial swelling and disappearance of crista,some nuclear membrane broken down,chromatin condensation and karyolysis.At post-maturation stage,intercellular space of the experimental group was wider than that of the control group.Conclusions Morphological and ultrastructure damage of ameloblasts may have occurred at the maturation stage in the process of dental fluorosis.Ameloblasts may be more sensitive to fluoride in dental enamel formation at maturation stage.