No abstract

Forty-six mentally retarded epileptic patients being treated with phenytoin and phenobarbital were studied to determine the root/crown length ratios. Forty-five mentally retarded patients not receiving anticonvulsant drugs provided the controls. Further, because serum phenytoin levels have been related to severity of gingival hyperplasia, efforts were made to determine if the hyperplasia was associated with dental root abnormalities and also whether these abnormalities could be related to epilepsy per se. Results showed that in certain teeth there was a smaller root/crown ratio in the patients taking anticonvulsant medication. The male patients were more affected than the female. The unusually short roots were not necessarily related to high serum phenytoin but the severity of gingival overgrowth was. Histologic study of teeth from patients taking anticonvulsants revealed developmental abnormalities and resorption.

By using the teeth for immobilisation and employing incident light microscopy at magnifications up to 240x, entire capillary beds could be observed in the labial gingiva in small laboratory animals. In the mandibular incisor region, simple capillary loops, as found in the human gingiva and nail bed, were absent in all species examined except in some guinea pigs. In the hamster, where the topography of the gingival capillary bed was studied in greatest detail, blood flow was regulated by changes in caliber of arterioles; by opening and closing of exits from main capillary channels into networks apparently devoid of vasomotor activity; and by opening and closing of arteriovenous anastomoses. Under certain conditions, settling of blood cells and blood cell clumps to the lower side of gingival veins, together with gravitationally layered flow, was observed.

No abstract

No abstract