L.S. Fosdick

Chemical Studies in Periodontal Disease

It has been shown that saliva from individuals suffering from periodontal disturbances will putrefy more rapidly than the saliva from individuals with normal periodontal tissues (1). The small differences noted were obtained by methods that determined only the increase in carboxyl groups and the increase in malodorous substances, and hence may not be a true measure of the actual rate of putrefaction. In the process of putrefaction, the protein molecule is probably first hydrolyzed to amino acids, after which the amino acids undergo decarboxylation, a deaminization and certain oxidation-reduction reactions (2). When a protein is hydrolyzed, each peptide linkage yields an amino group and a carboxyl group. Thus, if no further actions were involved, the formol titration, which determines the number of free carboxyl groups, would be an accurate indication of the amount of hydrolysis that had occurred. However, decarboxylation, deamination and oxidation-reduction reactions also occur. Furthermore, it has not been definitely established whether these reactions occur according to a definite sequence, or whether they may occur simultaneously. If the rate of hydrolysis were faster than the decarboxylation, there would be an accumulation of carboxyl groups and the formol titration would yield quite accurate results. If decarboxylation were faster than the hydrolysis, little change in the number of carboxyl groups would occur and the hydrolysis could not be estimated by this method. Of the amino acids progressively formed by hydrolysis during putrefaction, only a few, such as tyrosine and tryptophane, can be rapidly and accurately estimated in saliva by available methods. However, certain degradation products, such as indole from tryptophane, phenol from tyrosine, and sulfides from the sulphur-bearing amino acids, can be estimated, thus frunishing a rough measure of the amount of decarboxylation, deaminization and oxidation-reduction. Furthermore, many compounds formed by these latter reactions, such as cadaverine, skatole and sulfides, are malodorous, and hence may be detected in small quantities by means of the osmoscope. Mucin is rich in amino acids which yield these compounds (3). In the present continuation of the earlier work, the rate of putrefaction of the salivary proteins was measured by means of the formol titration and by estima-

Some Conditions that Effect the Odor Concentration of Breath

Fetor ex ore, or unpleasant breath has long been a common condition in man. Although the condition is known to be quite prevalent and is thought to be a reflection of some systemic condition very little data concerning the source and cause is available. Although it has been considered a valuable aid in diagnosis (1) (2), before it can become an accurate diagnostic aid more evidence concerning its source and cause should be found. From a theoretical point of view breath can be contaminated from three primary sources. The odors can be derived from the mouth, the lungs, and the nasal passages. Putrefaction processes in the mouth such as stagnant saliva, decaying teeth, pyorrhea, and degenerated cells on the tongue may give rise to odiferous substances which would contaminate the breath. Digestive disturbances in the stomach and small intestines may give rise to volatile substances which after absorption into the blood stream would be absorbed in alveolar air and excreted in the breath. Any putrefaction process in the lungs or in the nasal passages would also give off odiferous substances during the excursion of air in the process of breathing. In a recent paper (3) the authors described a method whereby the odor intensity of breath, lung air, and the odors derived from the mouth could be determined. By specialized apparatus the odors from the various sources were segregated, frozen in liquid nitrogen to concentrate them, and the intensity determined by means of an osmoscope (4). By these methods the odor intensity was given a significant mathematical term that could be used for statistical pur-

Chemical Studies in Periodontal Disease. IV. Putrefaction Rate as Index of Periodontal Disease

When the putrefaction rate of saliva is determined, values are obtained which seem to be related to the periodontal condition of the mouth of the patient from whom the saliva was taken. It has appeared that such saliva analysis might constitute a test for susceptibility to periodontal disturbances and that the test might be useful clinically as the now common salivary tests for caries susceptibility are useful. Accordingly, the present experiment was set up to determine how well the results of the salivary analyses correspond with clinical and radiographic findings in a fairly large group of patients.

Chemical Studies on Periodontal Disease—I

The causes and nature of the periodontal disease usually known as pyorrhea alveolaris have been under discussion for many years. At intervals new theories concerning the etiology of this disease have appeared. The condition has been attributed to uric acid (1, 2, 3), senility (4), salivary (5) and serumal calculus (6), mechanical irritations (7, 8, 9, 10, 11), micro-organisms (12, 13), including amoebae (14, 15), occlusal trauma (16, 17, 18, 19), and physiological disturbances (10). Because of so much contradictory evidence it is extremely difficult to arrive at any definite conclusions concerning the role of many of the factors that have been indicated as influencing the disease. From the evidence at hand it would seem that 2 major factors are involved, local and the systemic. Many believe that the former is of major importance, while others hold that the latter is the primary cause. Nevertheless, most authors suggest that both are involved. In view of the fact that many people with good occlusion and exceptionally clean mouths develop the conditionwhile otherswith poor occlusion and extremely dirty mouths do not, it would seem that local factors are not alone involved. This would indicate that certain individuals, normally, have either more or less resistance, or more or less susceptibility to the disease, regardless of the obvious local conditions of the mouth. A review of this literature reveals that most of the research concerning periodontoclasia has been primarily clinical, bacteriological, or histo-pathological in nature, with little emphasis on the exact chemical reactions that occur during the progress of the disease. On this basis, it is thought that a chemical study of the normal and diseased oral tissues and saliva should yield some information concerning the disturbances that occur during the disease, and perhaps shed some light on the fundamental causes. Pelzer (20) compared the phosphatase in blood from the gingivae with that from the finger. He found that in many cases there was a marked difference, particularly in those cases exhibiting bone destruction of the alveolar crest. Although the method used would not yield accurate results on the initial rate of reaction, the differences they observed were of considerable magnitude. These differences in phosphatase activity may furnish valuable information concerning the bone disturbances.

Studies in Periodontal Disease: II. Putrefactive Organisms in the Mouth

In 1939 the osmoscope (1) was adopted for use in measuring the odor intensity of breath (2). It was subsequently shown that periodontal disease was one of the major conditions that was associated with fetor ex ore (3), which suggested that periodontosis might be a putrefactive disease. It was further shown that the production of mal odors was primarily confined to the mouth (4), as a thorough cleansing of the mouth materially reduced the putrefactive odors. In 1943, it was shown that the salivary proteins from individuals suffering from periodontal disease actually putrefied and hydrolyzed much more rapidly than did the salivary proteins from normal individuals (5). This was shown by measuring the rate of odor production and by means of the formol titration. The fact that saliva from individuals with periodontal disease putrefies more rapidly than normal saliva suggests that bacterial action in the two types may be different. In view of this, it was thought interesting to investigate the action of pure strain organisms, isolated from the mouth, in an effort to determine which of the bacteria were capable of causing putrefaction and hydrolysis when allowed to act on human saliva. It is well known that most of the characteristics of the common mouth organisms have been studied, and it is known which of the organisms are capable of forming products of putrefaction; however, no work has been done under conditions similar to those which are found in the mouth. For this reason, human saliva was used as the test medium for this experiment. The conditions in the mouth are such that aerobic as well as anaerobic conditions are present. Furthermore, there is never a single strain of organism present, which makes possible many types of symbiotic action. For this reason, one series of tests was made using raw saliva. In these experiments large quantities of pure strain organisms were introduced into the raw saliva. The number of organisms used was so large that the number normally present in the saliva was small in comparison. Furthermore, the number of organisms present was sufficiently large so that the enzyme systems of the organisms could act even if no further growth occurred. In addition to the experiments wherein raw saliva was used, other experiments

The Effect of 2-Methyl-1,4-Naphthoquinone on the Incidence of Dental Caries

In 1943 it was suggested that the production of dental caries depends upon first, the rate of acid formation in the mouth, and second, the rate of neutralization of acid in the regions associated with the caries susceptible portions of the teeth (1). On this basis dental caries should be retarded by a decrease in the rate of acid formation or an increase in the rate of acid neutralization. Most of the successful methods of controlling caries have worked by decreasing the rate of acid formation. This is natural, because the rate of acid neutralization is controlled by many factors which at present cannot be materially changed (1). Probably the most successful experimental control of the rate of acid formation, with subsequent decrease in caries activity, has been accomplished by the reduction of fermentable sugars and carbohydrates in the diet (2, 3, 4), or by their elimination from the mouth through oral hygiene (5). These methods of caries control, however, depend entirely upon the cooperation of the patient. This cooperation cannot be expected of large masses of population. Another way of reducing the rate of acid formation is by interfering with the enzyme or co-enzyme systems which are necessary for acid production. Several agents may be used, some of which have been tried experimentally and some clinically. Iodoacetic acid has been tried experimentally with rats (6). It is probably too toxic for human use. A 30% urea solution (7), used as a mouthwash, acts as a protein denaturant, destroying the enzymes and hence preventing acid formation. A urea quinine mouth rinse has also proved successful (8). Ammoniacal silver nitrate reduced on the susceptible surfaces of the teeth leaves a deposit of colloidal metal which presumably retards fermentation (9). The enzyme inhibitor which has had the most wide-spread study and experimental use is the fluoride ion (10). This ion inhibits the hydrolysis of phosphoric esters and hence retards acid formation. Furthermore, the fluoride ion is absorbed by the dental enamel, forming a compound less soluble than unchanged enamel. Probably both actions are responsible for the success of fluorides in controlling or preventing caries. In 1942 (11, 12), it was found that synthetic vitaminK (2-methyl-1 ,4-naphthoquinone), when added in minute quantities to saliva-glucose mixtures, in vitro, would prevent the formation of significant amounts of acid. There was no evidence that its action as an enzyme inhibitor was closely associated with the vitamin activity. Preliminary experiments indicated that the material would

The Solubility of Normal and Fluoridized Enamel

SODIUM fluoride, when topically applied to the teeth, will cause a marked reduction in the caries activity.1 This treatment is now used extensively by public health services and by general practitioners. On the basis of the chemical properties of the fluoride ion and upon the current concept of dental caries, the effect may be due to an enzyme inhibition or to a change in the solubility of the inorganic portions of the tooth. It is known that the fluoride ion will inhibit the hydrolysis of phosphoric esters and hence interfere with the formation of acids from glucose.2 3 This inhibition of the hydrolysis of esters, however, requires relatively high concentrations of the fluoride ion before a complete cessation of acid formation is observed. A slight retardatio~n of acid formation is observable in concentrations of 1 ppm.4 In order to cause a retardation of acid formation, the fluoride ion must be in solution. This precludes a permanent or lasting effect by the topical application of fluorides. Insofar as the topical application of fluorides to the surface does produce a lasting effect, it is quite probable that the enzyme inhibitory action is of minor importance. In view of this, it is quite probable that the observed effect is due to a change in acid solubility of the enamel. Many investigators have found that fluoroapatite is less soluble than hydroxyapatite in acid solution.5 6 7 Fluoridized human enamel acts very similarly to fluoroapatite. The solubility of fluoroapatite and fluoridized tooth enamel has been studied quite extensively in various acid solutions,8 but insofar as the type of acid used is of less importance than the reaction of the solution, it was thought desirable to determine solubility in relation to the pH of the solvent and to formulate the conditions under which the fluoride ion would protect the teeth.

The Amino Acid Decarboxylase of Salivary Sediment

SEVERAL investigatorsl-5 have demonstrated that periodontal disease is accompanied by an above normal rate of putrefaction in the mouth. Amino acid decarboxylation is one of the major pathways of the putrefactive process and, as such, may be studied as an indication of the extent to which putrefaction takes place. The present work is an investigation of the presence and activity of the bacterial amino acid decarboxylases in saliva. A quantitative assay procedure is described which was used to correlate the salivary decarboxylase activity of clinic patients with their periodontal condition. The method is based on Gales studies6 of the amino acid decarboxylases of washed suspensions of intestinal bacteria.

Studies on the physicochemical phenomena related to dental caries. III. The effect of sucrose upon the solubility of human dental enamel.

SOLUBILITY studies on human dental enamel have engaged the attention of many investigators.-75 While the methods used have varied widely the purpose of most of the studies was to learn about the caries process or how to prevent it. Many investigations have dealt with the dissolving effect of various solutions; most of the solutions used were acidic in nature. The belief that carbohydrates and, more specifically, products of carbohydrate degradation were involved in caries formation gradually gained prominence over a span of years. This idea stimulated further research involving the effect of carbohydrate fermentation upon enamel. In addition, many investigators have sought to treat enamel to render it less soluble in acidic solutions. The results of these efforts by many workers have been to establish that carbohydrates serve as the main source for acid formation by fermentation and that this acid is directly involved in the decalcification process. It also has been shown that many substances (the majority of which are fluoride compounds) when applied to the enamel surface diminish the acid solubility of that surface. In none of the many studies, however, has the possible effect of sucrose per se on the enamel solubility been emphasized. The purpose of the present paper is to report a study which was designed to test the effect of sucrose on tooth enamel solubility in acid solutions. Sugars are accepted by most investigators as the principal substrate for acid formation in the mouth and thus are seen to play a direct role in dental caries. It is possible that sugars may affect the dental caries process in other ways in addition to that of acting as a source of acid. Such a possibility has prompted or influenced several investigations. For example, the effect of sucrose and other sugars upon tooth permeability has been studied.7678 The effect of sucrose upon ion diffusion through semipermeable membranes also has been investigated.79-81 The latter studies showed that sucrose changes the diffusion rates of hydrogen ions, calcium ions, and phosphate ions. This may possibly indicate that sucrose influences factors affecting the development of dental caries and therefore it is of interest to determine further influences of a physicochemical nature exerted by sucrose on the process of caries development. Preliminary studies in this laboratory82 showed a definite

The Reduction of Breath and Mouth Odors by Means of Brushing the Teeth

During the past decade there has been an elaborate program of public education in mouth hygiene by means of advertisements of various proprietary preparations. Some of the manufacturers sponsoring advertising campaigns have given particular emphasis to halitosis or fetor ex ore, calling attention to the social disadvantages as well as the health implications of this condition. The objective of the advertising propaganda is to educate the public in oral hygiene and to effect an increase in sales of a particular product. The latter objective is legitimate if the statements are not misleading and are substantiated by scientific evidence and if the product is beneficial to the public. In some cases the advertising propaganda has been offensive to professional ethics due to highly exaggerated claims and many unsubstantiated statements. This has brought the whole subject into disrepute with the truly ethical dentist. While there is no doubt that many people are afflicted with unpleasant breath, and are much concerned to reduce or eliminate this condition, unfortunately, there is little authoritative scientific evidence to support or refute the claims of manufacturers. The exact causes of this condition are not thoroughly understood nor has a detailed study of the results of various methods of control been made. In view of many conflicting statements and of the lack of any authoritative information regarding fetor ex ore, a comprehensive study of this condition, and the numerous variables that might influence it was considered desirable. In 1934, the osmoscope, an instrument whereby the odor intensity of air could be determined (1), was devised. This instrument made