Simon Katz

Uptake and release of chlorhexidine by bovine pulp and dentin specimens and their subsequent acquisition of antibacterial properties

Bovine pulp and dentin specimens were treated with either a 0.02 or 1.00 percent solution of chlorhexidine for either 20 or 40 minutes. Culture determination of the acquisition of antibacterial properties by the treated specimens immediately and 1 week after the treatment was evaluated using the test organism Streptococcus faecalis. It was concluded that chlorhexidine is a potent antibacterial agent under the test conditions and that its use as an endodontic irrigating solution should be further evaluated.

Influence of selected fatty acids upon plaque formation and caries in the rat

Weanling rats were given high-sucrose cariogenic diets containing 2 per cent lauric acid, linoleic acid, nonanoic acid or monolaurin. Plaque accumulation was determined on the incisors of half the animals during only the last 3 days of the study and on the remaining animals at the conclusion of a 21-day test period when both sulcal and smooth-surface caries were assessed. No significant differences between the test groups in food consumption were observed nor were there any differences in body weight gain. The least amount of plaque was observed in the animals given monolaurin; the other fatty acids exerted no significant effect upon plaque accumulation. The smooth-surface caries data indicated that the least number of lesions occurred in the animals on the diet containing monolaurin. Nonanoic acid was significantly more effective in limiting sulcal caries than any of the other fatty acids studied. Thus both monolaurin and nonanoic acid have significant cariostatic activity in the rat.

Effect of Water Soluble Components Derived from Cocoa on Plaque Formation

Cariostatic and antibacterial properties of cocoa and chocolate products have been reported. The presence in cocoa of tannins, theobromine, xanthine and anthocyanins has been proposed as possible causative agents (Madsen, Dietary Chemicals vs Dental Caries, Washington, Amer Chem Soc, 1970, p. 67). This study tested the effect of water soluble components of cocoa on plaque formation by Streptococcus mutans 6715. A water spluble extract of non-sweetened cocoa powdert (5% W/V) was obtained by autoclaving at 1210C for 15 min and then centrifuging the solution at 6000 rpm for 20 min. Chemical analysis revealed the presence of carbohydrate and protein: 84.06 mg/ml of total sugar (Dubois et al., Anal Chem 28:350, 1956) was obtained, and 18.22% of this sugar (15.78 mg/ml) was pentose (Brown, Arch Biochem 11:269, 1946). The anmount of protein was 89.88 mg/ml (Lowry et a ., J Biol Chenm X 93:26 5, 1 95 1). To test the effect on plaque formation, tubes containing 5 ml of complex basal medium (Jordan et al., J Dent Res 39:116, 1961) supplemented with sucrose (5% W/V), a micro-coverslip (11 x2.5 cm) and sterile cocoa extract in varying concentrations (4 tubes/concentration) were inoculated with 0.05 ml of a S. mutans culture grown for 18 hrs in CBM supplemented with 0.25% (W/V) glucose. The inoculated tubes were incubated at 370C for 18 hrs, and the coverslips were then removed, gently washed in distilled water and dried overnight in a 55°C oven. The coverslips were then placed in a fabricated specimen holder, and the light absorbances were measured at 350

In Vivo Plaque Measurement in the Rat

A method fox the in vivo measurements of plaque in the albino rat is described, in which plaque is stained with basic fuchsin and observed through an otoscope fitted with a magnifying glass. The method permits successive assessments in the same rat, and it is simple, reliable, accurate, and reproducible.

Further Studies Concerning the Placental Transfer of Fluoride in the Rat

Female rats were given 25 ppm fluoride as various fluoride compounds during gestation or 25 ppm fluoride as NaF during gestation and a pregestational period. Offspring were killed at birth and analyzed for fluoride. Fluoride compounds given during gestation resulted in comparable amounts of fluoride in the offspring, but a greater amount was observed in pups whose mothers received ZrOGeF6. Pregestational fluoride exposure increased the amount of transplacental fluoride transfer.

Enamel Conditioning for Fluoride Treatments

One of the limiting factors of the fluoride-enamel reaction is the close proximity of the enamel crystals. We proposed to loosen the structure of enamel somewhat to cause a favorable reaction with fluoride. The final phase of the process, for which the name enamel conditioning is proposed, is the retightening of the enamel structure (triggered by fluoride ions) and the incorporation of fluoride into the enamel crystals.

Enhancement of the Antiplaque Value of Antibacterial Agents by Enamel-Conditioning Methods: I. Rationale, Mechanism, and Initial Findings

A method is proposed to induce chemically the incorporation of bacterial agents into enamel and thus render this tissue resistant to bacterial colonization. It consists of promoting a slight initial dissolution of enamel, followed immediately by its reprecipitation. During this latter phase, antibacterial agents included in the test formulations would become trapped in the reprecipitating enamel. That this happens is proved by the chemical detection of antibacterial agents in treated enamel, as well as by the development of a remarkable resistance of treated specimens to grow in vitro plaque.

Enhancement of the Antiplaque Value of Antibacterial Agents Through Enamel-Conditioning Methods: II. Acquisition of Antiplaque Properties by Treated Enamel

Enamel specimens treated with systems containing enamel conditioners and antibacterial agents have previously been shown to incorporate the latter into the enamel. It has now been demonstrated that enamel blocks treated with these systems become highly resistant to bacterial colonization, that this effect is rather long lasting, and that the treated specimens prevent acid formation when incubated with Streptococcus mutans in a sugar-containing medium.

Effects of Solvent Extracts of Rice Bran and Free-fatty Acids Upon Plaque and Acid Formation

Marked inhibition of S. mutans plaque and acid formation was observed when solvent extracts of rice bran or several fatty acids were added to the culture medium. It is proposed that the effects observed with bran extracts are due to their fatty acid content. It would appear that the growth of, and acid formation by, microorganisms frequently mentioned in relation to dental caries can be controlled by a mixture of two or more fatty acids.

Enhancement of the Antiplaque Value of Antibacterial Agents by Enamel Conditioning Methods: III. Animal Results

Rat experiments demonstrate that adding a suitable antibacterial agent to a placebo dentifrice markedly reduces plaque accumulations on teeth brushed with the experimental product. When an enamel-conditioning vehicle is used instead of the placebo, the antiplaque effectiveness is increased many-fold.