Doran D. Zinner

EXPERIMENTAL CARIES INDUCED IN ANIMALS BY STREPTOCOCCI OF HUMAN ORIGIN.

Summary Streptococci were isolated from human dental carious lesions which reacted with fluorescein-tagged antisera against rat or hamster “cariogenic” streptococci. The human strains fell into 3 different categories, in fluorescence, morphology, microprecipitin and gel diffusion studies. One category, similar to the hamster strain, produced caries when used to infect hamsters. This occurred in 55 animals of 55 tested, and in no controls. The other 2 categories of human isolates failed to produce hamster caries; one of these is being studied for possible cariogenicity in germfree rats.

Epidemiologic Studies of Caries-Free and Caries-Active Students: II. Diet, Dental Plaque, and Oral Hygiene

Diet, extent of dental plaque, and oral hygiene scores for caries-free and caries-active students were significantly different. Results of this study suggest that these three parameters are contributing supplementary factors to the development of dental caries in the caries-active group. An experimental dietary questionnaire method used in this study may be used by dentists to identify children with a caries-conducive diet and to prescribe treatment accordingly.

Bactericidal properties of povidone-iodine and its effectiveness as an oral antiseptic☆

Abstract Povidone (polyvinylpyrrolidone)-iodine is an effective germicide. High dilutions are active in destroying, within fifteen seconds, the organisms commonly found in the mouth. It is effective in higher dilutions than the stock commercial preparations of the other common antiseptics studied. In 10 per cent aqueous solution, the antiseptic properties of polyvinylpyrrolidone iodine have been retained for more than one year. High dilutions, however, should be freshly prepared; color loss is accompanied by a weakening of germicidal activity. When povidone-iodine is used to prepare the oral mucosa for local anesthetic injection prior to dental procedures, the hazard of direct bacterial infection is removed almost completely. In the present study polyvinylpyrrolidone iodine was used in ninety-nine patients who received a total of 115 injections, and in only five instances were bacteria recovered from the injection needle.

Comparative pathogenicity of streptococci of human origin in hamster caries

A NUMBER of streptococci isolated from different host species, while possessing different antigenic and biochemical properties, appear to be related by their ability to induce experimental dental caries in animals. ORLAND (1955) induced experimental caries in germ-free rats with a strain of enterococcus; FITZGERALD, JORDAN and STANLEY (1960) also induced caries in germ-free rats, but with a different streptococcal strain (FA-1) of rat origin; and FITZGERALD and KEYES (1960) reported the development of experimental caries in hamsters with a streptococcal strain (HS-1) of hamster origin. The results of the work in experimental caries in animals suggested that dental caries in rodents was a specific bacterial disease in which certain strains of streptococci were of aetiologic significance. ZINNER et al. (1965a) reported the isolation of streptococcal strains from human carious lesions that were morphologically and antigenically similar to either the hamster (HS-1) or the rat (FA-1) strains. The human hamster-like strain, AHT, induced experimental caries in hamsters and the rat-like strain, BHT, induced caries in gnotobiotic rats (ZINNER et al. 1965b), both animal species requiring a special cariogenic diet (KEYES, 1959). In preliminary studies of human carious lesions it appeared that AHT-type strains were associated with severe, active, and rapidly progressive lesions while the BHTtype strains were associated with slowly progressive lesions (ZINNER ef al. 1965b). The present study compares the cariogenic activity of both strains in hamsters. Nineteen-day old hamsters, albino and golden, weighing 30 g, were maintained on a cariogenic diet (KEYES, 1959) and orally infected with AHT or BHT strains by established techniques (FITZGERALD et al. 1960). The albino hamsters were supplied originally by the National Institute of Dental Research and maintained at the National Children’s Cardiac Hospital for the past 5 years. The golden hamsters were purchased locally and the colony has been maintained since 1959.

Epidemiologic Studies of Caries-Free and Caries-Active Students : I. Prevalence of Potentially Cariogenic Streptococci

No significant difference was found in the prevalence of four potentially cariogenic streptococcal serotypes on molar surfaces of caries-free and caries-active students. Presence alone of these organisms did not correlate with the caries status of the individual. Other supplementary factors, apparently, are necessary for the induction of caries. Quantitative microbiologic procedures are needed to establish a more definitive elucidation of the role of specific microbiota in human dental caries.

Viruses of Cariogenic Streptococci

Eight cariogenic strains of Streptococcus mutans and one cariogenic strain of Streptococcus salivarius lysed after exposure to ultraviolet light, mitomycin, nitrosoguanidine, and streptomycin. Each of these strains released a virus with a similar morphology after ultraviolet light and mitomycin induction. Neither lysis nor a virus was demonstrated in several noncariogenic strains of streptococci.

Identification of Types of Potentially Cariogenic Streptococci on Human Tooth Surfaces by the Fluorescent Antibody Technique

The frequency distribution of four potentially cariogenic streptococcal types, AHT, BHT, GS-5, and HHT, on seven specific maxillary and mandibular tooth surface segments of 27 male teenagers was investigated. BHT and HHT serotypes were widespread in the dentition of all subjects. AHT and GS-5 organisms were identified in 7 and 89% of the population studied, respectively.

Bone Loss and Caries in Rats Infected with Human Streptococci

Gnotobiotic rats infected orally with various human cariogenic Streptococcus mutans strains or a Streptococcus salivarius strain exhibited greater alveolar loss of bone than control rats. The same strains also showed considerable differences in their cariogenic activity. There was a positive correlation between the extent of bone loss and carious surfaces.

Quantitation of Streptococcus mutans by the membrane filter fluorescent antibody technique

Abstract The aetiologic relationship of Streptococcus mutans to human dental caries may be of a quantitative nature. For the quantitation of these organisms, the fluorescent antibody technique (FA) was adapted for use in conjunction with the membrane filter technique. Membrane filters with a porosity of 0.45 μm were adequate for doing total colony counts of the oral flora and for screening Strep, mutans strains AHT, BHT, GS-5 and B13, Bratthall serotypes a, b, c and d, respectively. In the FA technique, the filters containing the samples were incubated anaerobically overnight on mitis-salivarius agar (Difco). Total colonies were counted and the filters were then stained for 30 min with fluorescein-labelled antisera specific for strains AHT and GS-5. The short incubation time was a distinct advantage. The Strep. mutans colonies were small and showed a sharp, bright fluorescence following staining. They could readily be differentiated from autofluorescent colonies which were much larger and had a hazy fluorescence. In addition, a bivalent fluorescent antiserum mixture was useful in quantitating strains AHT and GS-5 in one step. It is suggested that a mixture of a broader range of antisera to cover all serotypes of Strep. mutans could be useful in the total quantitation of Strep. mutans in dental plaque samples.