No abstract

A method which could detect oral micro organisms in the exact location of their occurrence would reveal much concerning their role in dental caries. Most of the caries activity tests determine the presence of micro organisms in the saliva and not in situ. The detection and identification of oral micro-organisms in the carious lesion itself could help diagnosis and treat caries.Irreversible hydrocolloid full-mouth impressions were taken of dental clinic patients. The imprcssion material was carefully placed in the mouth and removed, so that a minimum of streaking of the dental plaque would occur. The impressions were boxed in wax and immediately poured with fortified selective agar medium. The medium was kept at 47' C., so that it would solidify on contact with the hydrocolloid. The poured impressions were chilled, and the agar medium model (Fig. 1) was carefully removed from the impression material. FIG. 1 (left).-Agar medium model. FIG. 2 (right).-Lactobacilli in the areas of open various lesions.Two selective media were used. The medium used for the isolation of oral lactobacilli was a modification of the formula of Rogosa, Mitchell, and Wiseman (J. Bact., 62:132, 1951). It consisted of lactobacillus selective broth containing brom-cresol green, 0.02 gm/liter, and 3 per cent fortified agart and adjusted to pH 5.5. Agar models were incubated anaerobically at 370 C. for 48 hours.The selective medium used for the isolation of oral yeasts was Sabouraud's dextrose broth containing penicillin, 20 units/ml; cyclohexamide, 0.5 mg/ml; streptomycin, 40 mg/ml; and 3 per cent fortified agar. Agar models from this were incubated at 300 C. for at least 72 hours. The modified LS medium showed lactobacilli in the areas of open carious lesions (Fig. 2). The yeast selective medium models had a growth of oral yeasts in the vicinity of carious lesions and in areas of chronic oral irritation. This technique, which transferred the micro-organisms from the oral tissue to the impression material and then to the agar model, localized the oral micro-organisms so that they could be related to the lesions in which they resided.

Sprague-Dawley rats, which are not susceptible to the teratogenic effects of adrenalectomy, adienal corticoids, and corticotropin noted in other species, were subjected to amniocentesis and to amnioceutesis plus adrenalectomy.Amniocentesis was shown to be teratogenic when performed at any time between the fourteenth and eighteenth gestational days inclusive, but no malformations occurred either in control fetuses or when amniocentcsi.; was performed on the thirteenth day of gestation. Fetal resorptions were increased following single amniocentesis on any gestational day from the thirteenth to the eighteenth inclusive. The predominant defects induced were cleft palate and limb deformity. Cleft palate occurred only after amniocentesis on the fourteenth, fifteenth, or sixteenth days of gestation, principally on the fifteenth day. However, limb deformity, consisting primarily of malrotation, syndactyly, and varying degrees of agenesis, occurred following single amniocentesis on any day of gestation from the fourteenth to the eighteenth inclusive, but principally on the fifteenth day. Adrenalectomy did not alter significantly either the nature or the incidence of the anomalies induced by amniocentesis.The data indicate that amniocentesis is teratogenic in the rat, and that the adrenal glands arc neither essential for, nor do they exert any detectable influence upon the induction of those malformations.