Samuel Dreizen

The Influence of Sodium Bisulphite on Acid Production in Saliva

The rdle of acids in tooth decalcification (1) is now generally accepted. As a result recent attempts at dental caries control have been in the direction of decreasing the rate of acid formation in the mouth, and/or increasing the rate of acid neutralization in regions associated with the caries susceptible portions of the teeth (2). Since the latter has been considered difficult to achieve, methods and means of decreasing the rate of acid formation in the mouth have been the aim of most of the recent investigations in this field. Controlled diet, oral hygiene, and interference with the enzyme or coenzyme systems necessary for carbohydrate degradation have each presented distinct possibilities. Chemical inhibitors of enzyme systems has been studied by Stephan (3) using urea, Zander (4) using ammoniacal silver nitrate, Dean, Jay, Arnold, and Elvove (5) using the fluoride ion, and most recently Burrill, Calandra, Tilden, and Fosdick (6) using synthetic vitamin K. These investigators have all succeeded in reducing significantly the rate of acid formation in the saliva. The work of Burrill, Calandra, Tilden, and Fosdick (6) was particularly interesting because a 2-methyl 1,4-napthoquinone-sodium bisulphite addition compound was employed. The results were attributed to the quinone which was regarded by these investigators as the active ingredient, the sodium bisulphite being used for the purpose of rendering the 2-methyl 1,4-napthoquinone water soluble so it would be more rapidly absorbed (7). Sodium bisulphite, however, has had some use in medicine as an antiseptic and an antifermentation agent (8). The possible effect of sodium bisulphite on the results obtained by Burrill, Calandra, Tilden, and Fosdick stimulated investigation in regard to the action of this salt on the process of acid production in saliva. Since Burrill and his associates used less than 0.75 mg. sodium bisulphite in their study with 2-methyl 1,4-napthoquinone (6), a series of preliminary tests were made using varying concentrations of sodium bisulphite. It was found that values ranging from 2.5 mg. to 10 mg. showed a definite interference with the acid formation, the most efficient concentration ranging from

Observations on the relationship between selected B vitamins and acid production by microorganisms associated with human dental caries.

M ANN, Dreizen, Spies, and Hunt,1 in 1947, found that persons with multiple B vitamin deficiencies of many years standing had little or no dental caries activity. Subsequently, Dreizen, Reed, and Spies2 noted that acid production by oral flora in saliva-glucose mixtures is related to the nicotinic acid content of this secretion. Human saliva contains, in addition to nicotinic acid, variable amounts of thiamine, riboflavin, pyridoxine, pantothenic acid, folic acid, and biotin.3 Because of their growth-promoting properties and coenzyme functions, differences in the availability and usability of these vitamins may constitute a prime limiting factor in the acid-producing microbial spectrum of the dentobacterial plaque. Acidogenic oral lactobacilli, streptococci, staphylococci, and yeasts have been singled out as possible initiators of or contributors to the caries process.5-13 Microorganisms differ in their B vitamin requirements and in their ability to synthesize these compounds or to utilize closely related chemical substances. The extent to which the oral acidogens differ in this respect has been determined by a series of investigations designed to establish: (a) the B vitamin needs of representative species of oral acid-producing microorganisms; (b) the effect of the deletion of each of the B vitamins present in human saliva on acid production by oral acidogenic flora; (c) the effect of the addition of a metabolic analogue of nicotinic acid on the growth of pure and mixed cultures of selected oral acidogens; and (d) the effect of the addition of this agent on acid production in human saliva.

Human Tooth Structure as a Bacterial Culture Medium

Whereas the microbial growth-promoting properties of human saliva have been the subject of numerous investigations (N. B. WILLIAMS, D. Pract., 3:265, 1953), little is known of the bacterial growth-supporting capacity of human tooth structure. The following in vitro studies were undertaken to obtain such information. Eight samples of paraffin-stimulated whole saliva and 8 carious teeth served as the source of the test organisms. The carious teeth had been thoroughly cleaned of extraneous matter after extraction and stored in empty screw-capped jars at 6° C. for more than 5 years. Primary cultures from each saliva sample and carious tooth were grown in 10 ml. of thioglycolate broth incubated at 37° C. for 24 hours. Inoculums were prepared from the 24-hour cultures by washing the organisms in physiologic saline solution as previously described (S. DREIZEN and T. D. SPIES, J. dent. Res., 26:409, 1947). One drop of each inoculum was seeded into duplicate tubes containing 100 mg. of ground tooth structure and 5 ml. water, the suspension having been autoclaved prior to use. The ground tooth material was obtained by pulverizing 15 cleaned, caries-free human teeth in a laboratory mill* fitted with a 2-mm.-mesh sieve. The powder was pooled and mixed before weighing and dispensing. One set of inoculated tubes containing powdered tooth was incubated at room temperature, the other at 370 C. After 24 hours, one loopful from each powder-containing tube was placed in 10 ml. of thioglycolate broth. The organisms recovered after incubation in this medium were then identified by conventional bacteriologic methods. They were cultivated in pure culture and reseeded into tubes containing powdered tooth and water in the aforementioned manner. Every 24 hours, single loop aliquots from each tube were returned to fresh thioglycolate broth. This procedure was continued until growth in thioglycolate medium could no longer be detected turbidimetrically. Each of the eight samples of whole saliva yielded an organism that tolerated the dispersion of tooth structure in water. Specifically, these included five