Effects of diphenylhydantoin on teeth in rabbit.

The drug diphenylhydantoin (DPH) is well known to affect the gingiva of humans. Among other known unwanted effects is that on calcified tissues. The initial purpose of our study was to examine the effect of chronic administration of DPH on the continuously erupting incisors of the rabbit. While studying the dentin a second investigation was undertaken when it was noticed that the pulps in DPH-treated rabbits were apparently more vascular than those in the control rabbits. After a treatment period of from 5-6.5 weeks the rabbits were killed, the jaws decalcified, sectioned and stained. The results presented here show that the animals treated with DPH developed less dentin. The pulps from the DPH-treated animals showed a greater area occupied by blood vessels. These experimental results are of interest in view of reported clinical findings that some patients treated with DPH develop smaller teeth with blunted apices. The vessel changes remain unexplained.

Immune response to keyhole limpet hemocyanin and oral Actinomyces viscosus antigens in Macaca arctoides.

The humoral and cell-mediated immune response to keyhole limpet hemocyanin and antigens from a monkey oral strain of Actinomyces viscosus were investigated in Macaca arctoides. Prior to immunization no responses were detected. Immunization resulted in the production of antibodies to both antigen preparations, the development of a positive skin test and significant stimulation of peripheral blood lymphocytes using the in vitro lymphocyte blastogenesis technique. Furthermore, these responses were continuously detectable for more than 1 year postimmunization with keyhole limpet hemocyanin and for up to 6 months postimmunization with A. viscosus antigens. The capability of developing immune responses in these animals, particularly to A. viscosus antigens, added further to their use as a model for the study of the role of the host immune response to these antigens in the pathogenesis of human periodontal disease.

Interaction of macrophages and lymphocytes in rat skin allografts.

Light microscopy of 2 microgram sections of rejecting rat skin allografts, embedded in hydroxyethyl methacrylate, revealed among the cells infiltrating the graft base extravascular macrophages containing a small lymphocyte. Toluidine blue staining indicated DNA degradation in some of these phagocytosed lymphocytes. More frequently small lymphocytes were in intimate contact with the surface of the macrophages, resembling "Periopolesis', which others have previously observed in vitro. These macrophage-lymphocyte interactions were not seen in sections of autografts. Despite a previous report that diphenylhydantoin (phenytoin) impairs macrophage function, these macrophage-lymphocyte interactions were present in grafts placed in rats receiving this drug. This treatment did not hasten or delay the onset of graft rejection. These in vivo findings both accord with recent in vitro studies on the mechanisms of phagocytosis and with reports that phagocytosis is one of the effector mechanisms in allograft rejection. However, macrophage phagocytosis of lymphocytes has also been observed in testicular lymph collected from conscious normal sheep.

Dental root abnormalities and gingival overgrowth in epileptic patients receiving anticonvulsant therapy.

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.

Use of chlorhexidine gluconate to inhibit dental plaque accumulation in Macaca speciosa.

Oral swabbing with 2% aqueous chlorhexidine gluconate together with thorough approximal flossing effectively reduce plaque accumulation to negligible levels in M. speciosa.

Improved technique for anaestesia of Macaca speciosa with methohexitone sodium.

Injection of methohexitone sodium, 5% w/v in 0.9 % saline, into the deltoid muscle at a dose of 16-17 mg/kg bodyweight was satisfactory for dailty general anaesthesia of Macaca speciosa monkeys.

Effects of chronic administration of sodium diphenylhydantoin ('Dilantin') on bones and teeth of the rat and hamster: a preliminary study.

Male Charles River rats, 31-days old, received i.p. injection of sodium diphenylhydantoin (DPH), 100 mg/kg in 0.9% NaCl, once daily for 26-27 days before death. Male Syrian hamsters, 40-days-old, received similar injections of DPH, 25 mg/kg for 46 days, no treatment for 39 dyas, then DPH FOR A FURTHER 17 DYAS BEfore sacrifice. All rats receiving DPH gained less weight than the controls, and more than 50% displayed acute neurotoxic reactions to the drug; hamsters were not so affected. Morphology and composition of caudal vertebrae, teeth, and jaws from control and DPH-rats were compared on the basis of measurements on radiographs and gross specimens, histological investigation, and determined of % dry volumes of ash, volatile inorganic component, lipid, and organic matrix. DPH-bertebrae were smaller and showed impaired osteogenesis; but chondrogenesis was similar to controls. Overall tail length was similar in both animal groups because caudal intervertebral spaces were wider in DPH-rats, compensating for reduced longitudinal growth of corresponding vertebrae. Incisors were smaller and third molar roots shorter in DPH-rats. In DPH-hamsters the attachment of the periodontal ligament to maxillary incisors was deranged. DPH administration did not change the composition of rat bone or teeth. Densities of dry bones and teeth were in accord with their composition. Possible modes of action of DPH are discussed. Species differences in response of mineralized tissues to DPH administration are emphasized in relation to reports of rickets and osteomalacia in patients on long term DPH therapy.