Effects of molybdenum, strontium and their combination on dental caries in the rat

The effect of Sr and Mo alone or in combination on dental caries has not extensively evaluated and still a subject of controversy. To investigate this effect, rats were given weaning 50 ppm Sr and 1 ppm Mo alone or in combination via the drinking water. The control group was given distilled water. The rats fed a formulated cariogenic diet from 21 to 71 days of age, were killed and the first, second and third molars were evaluated for carious lesions. Strontium and molybdenum or their combination decreased the number and the extent of enamel and dentin caries of molars erupted at the time of the elements administration. For third molars where the elements were given before and after its eruption, Sr and its combination with Mo decreased the caries. However, the Mo alone did not produce significant caries reduction. The results demonstrate that Sr and Sr + Mo combination has a pre- and post-eruptive cariostatic effect whereas Mo has a post- eruptive effect only. Also, it demonstrates that the Sr and Mo did not have synergistic effects

Histological and histochemical study of radiation effect on the specialized oral epithelium

The study was carried out on 60 healthy albino rats, seven days of age divided into two groups one as a control and the other received single whole body gamma irradiation at a dose level 3 gray. Irradiation was performed using gamma cell 40 manufactured by atomic energy of Canada Limited. The surviving rats were sacrificed serially one, two and three weeks after irradiation. The tongue specimens were dissected and each one divided into two halves longitudinally, the right one prepared and used for histological and histochemical study, while the other half was prepared for the determination of DNA synthesis. All the experimental rats were affected by irradiation and the tongue papillae specially the filiform type was greatly affected, the epithelium became thinner than normal with less thickness of keratin layer specially two and three weeks after irradiation, loss of taste bud in fungiform and decrease in number of taste buds in circumvallate papillae. Histochemically, both the alkaline phosphatase and acid phosphatase. enzymes in the epithelium of irradiated rats were greatly affected. On the other hand, the rate of DNA synthesis diminished by 32 percent after one week of irradiation, 53 percent after two weeks and 76 percent after three weeks. From the histological, histochemical, and the DNA synthesis results, we can conclude that, whole body gamma irradiation not only affect the epithelium covering the tongue but also, affect the taste buds and disturb the process of DNA synthesis of the tissue, as well as, affect its enzymatic activity