Search

EDTA-soluble material, extracted from incisor teeth of rats given 50 ppm fluoride (NaF) in drinking water ad libitum from conception to age nine wk, contained significantly higher levels of protein (P less than 0.01) and gamma-carboxyglutamic acid (P less than 0.01) than did similar material from control rats. Tooth fluoride levels indicated that the incisors were mildly fluorosed. Analysis of these data indicates that mild fluorosis of rat incisor teeth involves not only the characteristic disturbances of pigmentation and mineral structure but also some alteration of the matrix protein.

Various doses of sodium fluoride (NaF), salmon calcitonin (CT) and NaF combined with CT were given intravenously to rats (236 +/- 2 g). Blood plasma samples were collected at various times up to 24 hours and measured for total calcium (adjusted for variation in plasma albumin), inorganic phosphate, ionic fluoride, urea, and creatinine. Following injection of NaF alone, significant hypocalcemia and hyperphosphatemia was observed. In contrast, CT injections resulted in hypocalcemia and hypophosphatemia. NaF and CT given in combination generally resulted in the hypocalcemia being equal to or greater than that calculated from the simple addition of their individual effects. Significant increases in both plasma creatinine and plasma urea were observed following treatment with NaF alone or with CT and NaF together, whereas CT alone had negligible effect. These results suggest that NaF does not mimic the effects of CT; rather that NaF and CT interact to modify their individual effects. The influence of NaF probably occurs via an effect on kidney function.

Over a 24-h period, Wistar rats from 4 litters, 6 to 9 days old, were given five intraperitoneal injections of a solution of 0.9% sodium chloride containing sodium fluoride (3 mg F/kg body weight). Within-litter controls were used. All rats were killed by decapitation 2 h after the final injection and the rat heads, cut sagittally, were processed for protein histochemistry. The intensity of staining of the protein in the enamel matrix of the upper jaw molar tooth buds was quantified using the two-wavelength method of microphotometry. A significant increase in the intensity of staining of fluoride-treated tissues over controls was observed with the histochemical methods specific for arginine (P less than 0.01), tyrosine (P less than 0.05), and cysteine (P less than 0.05). Other histochemical methods specific for amino acid groups failed to show any significant difference between fluoride and non-fluoride-treated enamel matrix.

Staining reactions for a number of histochemical procedures for lipophilic staining and protein were studied in the enamel matrix along the length of rat incisors. Sudan Black gave a positive stain across the whole thickness of very early enamel (up to 30 micrometer) but this staining only continued as a narrow band close to the ameloblasts as the enamel matured. A variety of tests for protein produced almost identical staining patterns in enamel matrix up to 100 micrometer thick. Since the pattern of "lipid" staining persisted, after using a number of procedures which could normally be expected to remove lipid, it is suggested that Sudan Black positive staining may be due to lipophilic protein rather than lipid itself. Fluoride did not significantly alter the staining reactions for "lipid" and protein but did produce matrix which was much more effectively stained by cross-linking agents FFDNB and FF sulphone.

The article discusses a study on the effects of molybdenum and fluoride on the tooth morphology of rats. Researchers gave intraperitoneal injections of molybdenum and fluoride to rats. They found that these injections did not influence the size of the teeth. However, fluoride and molybdenum did cause variations in the widths of fissures as well as the amount of dentin and enamel that lined the fissures.

The article discusses the use of scanning electron microscopy in studying fluorosed dental enamel in rats. Rats can be given intraperitoneal injections of fluoride to cause dental enamel mottling. This dental enamel can then be examined using scanning electron microscopy. Images produced in this manner can be studied to gain a better understanding of mottled enamel. Photographs accompany the article.