The inhibitory effect of hydrolytic products of starch on in vitro colonization by Streptococcus mutans.

Synthetic culture medium containing potato starch and 1 gm% sucrose, with and without human parotid saliva, were pre-incubated. Filtrates from these mixtures were then incubated with Streptococcus mutans. S. mutans colonization on glass rods was suppressed in the cultures using filtrates from saliva and starch interaction. No inhibition was noted in filtrates pre-treated with parotid saliva in the absence of starch. The results suggest that the hydrolysis of starch by saliva yields by-products which inhibit in vitro S. mutans colonization.

Cell-mediated immune response to fractionated products of Actinomyces viscosus cultures.

Since bacterial invasion of host tissue has not been shown to occur in the course of periodontitis, many investigators believe that products released from dental plaque microorganisms enter the tissue and elicit a series of host responses leading to the pathological condition. This study, therefore, was designed to explore the possibility that cell-free products isolated from Actinomyces viscosus cultures are able to induce cell-mediated immunological responses in experimental animals. Hartley strain guinea pigs were sensitized with concentrated cell-free products of A. viscosus culture supernatant fluids mixed with Freund complete adjuvant. After 10 to 17 days the animals responded to challenge with this material with skin reactions indicative of delayed-type hypersensitivity. Furthermore, cells isolated from sensitized animals produced mitogenic factor and macrophage migration inhibition factor (MIF) when cultured with the material. The cell-free culture products were fractionated by column chromatography and electrophoresis. Several partially purified components were shown to induce cell-mediated responses in guinea pigs as determined by skin tests and by mitogenic factor and MIF assays. It is apparent that this single microorganism associated with dental plaque is capable of producing several substances which can induce a cell-mediated immune response and subsequent tissue inflammation in laboratory animals.

Effect of temperature on collagen-dissolving ability of sodium hypochlorite endodontic irrigant.

The collagen-dissolving ability of both 2.6% and 5.2% sodium hypochlorite endodontic irrigating solutions was compared at room temperature (21 degrees C) and body temperature (37 degrees C). The 2.6% sodium hypochlorite solution at a temperature of 37 degrees C. was found to be equally effective as a collagen-dissolving agent when compared to 5.2% sodium hypochlorite at either 21 degrees C. or 37 degrees C.

The effect of disaccharides on the plaque-forming potential of Streptoccoccus mutans.

The comparative and combined effects of sucrose, maltose, and lactose as factors on the plaque-forming potential of Streptococcus mutans were assessed. With increasing additions of maltose to sucrose-supplemented medium there was decreasing plaque formation. Lactose additions slightly increased plaque formation, but when combined with maltose they significantly enhanced the maltose inhibition of plaque formation.

Electrophoretic patterns of parotid fluid proteins from caries-resistant and caries-susceptible individuals.

Parotid saliva samples from caries-resistant and caries-rampant individuals were electrophoresed on polyacrylamide gel slabs. The parotid saliva of the caries-rampant group showed a significantly higher level of anodemigrating proteins, predominantly isoamylases, and a significantly lower level of cathode-migrating proteins than that of the caries-resistant group in both paraffin-stimulated and sour lemon-stimulated salivary flows.