Experimental Caries Research Articles

Experimental Dental Caries in Rats

Experimental Dental Caries in Rats

Observations on Experimental Dental Caries. XI. Influence of Pregnancy

SummaryThe influence of pregnancy on caries activity has been studied in hamsters reared from weaning for 100 days on a sub-optimal diet, with their respective litter-mate controls. The results show that pregnancy does not influence caries activity in any direction.

The Effect of Carbohydrates on Experimental Caries in the Rat

The Effect of Carbohydrates on Experimental Caries in the Rat

The Effect of Topical "Septochem" Applications on Experimental Caries

The Effect of Topical "Septochem" Applications on Experimental Caries

Effect of Age on the Incidence of Experimental Caries in Normal and Castrate Female Rats

Attention has recently been focused on the problems of aging of dental structures by Robinson, Boling and Lischer (1). Although these authors have compiled an imposing list of references concerning the changes in the teeth and jaws with age, little is known of the effect of age on experimental caries in the rat. Most of the studies on caries in rats (2-19) have been made over relatively short periods and on young animals. Only a few studies (20-26) have included rats of advanced age or rats which have been observed over a period of 1 year or more. From these long-term studies the general impression is gained that rats on adequate dietary regimes do not develop caries, whereas those fed deficient diets may have carious teeth. No data are available on the incidence of caries in old rats placed on the coarse corn diet. A colony of 17 normal and 12 castrate female rats were put on the Hoppert, Weber, and Caniff diet (3) at the age of 1 year. They were maintained on this diet until death from old age or other causes supervened, with the exception of 4 rats which were sacrificed after 19 months on the diet in order to end the experiment. At death the jaws were removed and the teeth examined under binoculars (15X) according to the technique previously described (25). Missing cusps and microscopic lesions were recorded although it was frequently difficult to distinguish between fractures and carious lesions in the presence of advanced attrition. The data on the normal rats are given in Table I. It is interesting to observe that little evidence of caries was found in some of the rats after periods as long as 13 months on the experimental diet. The number of cavities, the number of cusps involved, and the number of teeth totally destroyed are seen to increase with increasing time on the diet. In Table II are given the corresponding data on the castrate female rats. None of these had any caries up to 9 months on the diet. As in the case of the normal animals the numbers of cavities, of cusps involved, and of teeth totally destroyed increased with the time on the diet. There is little difference between the observations on the normal and on the castrate female rats. The normal rats averaged 2.8 cavities per rat; the castrates 2.2. The normal rats averaged 7.5 cusps involved per rat; the castrates 5.8. The normal rats averaged 0.9 teeth totally destroyed per rat; the castrates 0.7. There is apparently a tendency for the normal rats to have somewhat higher average values per rat. However, these differences can be accounted for by the

The Mechanism by Which Iodoacetic Acid Inhibits Experimental Dental Caries in the Rat

The Mechanism by Which Iodoacetic Acid Inhibits Experimental Dental Caries in the Rat

Inhibition of Experimental Dental Caries in the Rat by Iodoacetic Acid

Inhibition of Experimental Dental Caries in the Rat by Iodoacetic Acid

Dietary Repair of Experimental Caries

Dietary Repair of Experimental Caries

Dietary Repair of Experimental Caries

Dietary Repair of Experimental Caries

Bacteriological Studies on Experimental Dental Caries in the Rat: I. Bacterial Flora of Normal, Non-Carious Teeth

Journal Article Bacteriological Studies on Experimental Dental Caries in the Rat: I. Bacterial Flora of Normal, Non-Carious Teeth Get access R. W. Harrison R. W. Harrison From the Walter G. Zoller Memorial Dental Clinics and the Department of Bacteriology and Parasitology, University of Chicago Search for other works by this author on: Oxford Academic PubMed Google Scholar The Journal of Infectious Diseases, Volume 67, Issue 2, September 1940, Pages 91–96, https://doi.org/10.1093/infdis/67.2.91 Published: 01 September 1940 Article history Received: 06 July 1940 Published: 01 September 1940

Bacteriological Studies on Experimental Dental Caries in the Rat: II. Changes in Tooth Surface Flora Associated with Development and Inhibition, of Dental Caries

general the same groups of microorganisms that are found in the normal, non-carious oral flora. These findings indicate that if the cause of caries is bacterial it lies in increased incidence or increased activity of organisms already present, in species or varieties not easily distinguished from closely related forms commonly present in the normal flora or in forms not readily isolated by the laboratory methods ordinarily used. There have been many studies2,3 showing that lactobacilli, though often found in human mouths showing no evidence of caries activity, are increased markedly in numbers in active dental caries. This is presumably true also of certain streptococci.4-6 The results of several investigators7-9 have shown that the oral micro-organisms commonly believed to be associated with human caries are also found in the oral flora of the rat. The present series of studies was undertaken to try to determine, first, whether there are any significant changes in the oral flora which can be shown to be associated with the development of dental caries and, second, if the production of caries in rats could be prevented by chemical means, whether there would be at the same time inhibition of any of the flora of the carious mouth. In the preceding paper9 the various micro-organisms in the normal oral flora were considered

A Method for Staining of Carious Lesions in Teeth.

In the study of experimental rat caries large numbers of animals must be employed to obtain significant statistical results. As a result the methods for examination of the molar teeth become very important. Some investigators have employed the very tedious method of preparing stained thin-sections by the ordinary technics. Others have attempted to reduce the time and expense by resorting to either gross inspection of the carious teeth or to rapid grinding and examination of ground sections. At the suggestion of Dr. B. F. Miller of the University of Chicago the author has developed a rapid, simple and precise method for the staining of carious areas in rat molars (and also in human teeth). Previously,1 the author had developed a method for the demonstration of insoluble calcium salts in the tissues. It was found that this method cannot be applied to the study of teeth because the silver solution used in the techmc will not penetrate the dense dental tissues. Dentin will get a very superficial black coating...

Inhibition of Experimental Dental Caries by Fluorine in the Absence of Saliva.

Although the inhibition of dental caries by fluorine has been demonstrated in endemic areas1, 2 and in laboratory rats fed on a caries-producing diet3, 4 the mechanism by which the action takes place has not yet been adequately demonstrated. Armstrong and Brekhus5 found a higher fluorine content of sound enamel than in carious and offered the hypothesis that this may be the factor responsible for the inhibition. In this report we have attempted a further investigation of this mechanism. Since the enamel of the molar teeth of the animals used was fully formed before fluorine was applied it would appear that the action of fluorine must be due to its being held in the region of the tooth surface or, as far as the dentin is concerned, to the possibility of fluorine reaching it through the circulation.Previous studies are inclined to disregard the ability of fluorine becoming incorporated into the tooth surface after formation and thus causing an increased resistance to the mechanism responsible for decalcific...

Effects of Selective Salivary Gland Extirpation upon Experimental Dental Caries in the Rat.

ConclusionsDisturbance of normal salivary flow in the rat results in an increased incidence of experimental caries. The effect is most marked in rats with retained mucous saliva on a caries-producing diet and is in direct proportion to the amount of serous saliva removed. Caries production has even been observed in operated rats deprived of their serous saliva when fed a diet known to produce minimal dental destruction. The lower ratio of fracture to carious lesions in rats with such saliva indicates that the rate of development of carious lesions in these groups is very rapid.

Susceptibility to Dental Caries in the Rat

It is apparent that several dietary factors cooperate in the production of experimental dental fissure caries in rats. The lesions are due primarily to the ingestion of particles of coarsely ground raw cereal, such as rice or corn, included in the diet from the time of weaning; but other dietary conditions influence the prevalence of caries in significant degree (7, 8, 9). This report presents the results of further studies of some of these secondary or modifying influences on caries produced with coarse rice and corn diets.

Bacterial Flora in Experimental Dental Caries of the Rat

According to Miller's theory dental caries is caused by acids elaborated by microörganisms. Of the acidogenic and aciduric bacteria present in the plaques covering early lesions and in the carious dentine of advanced cavities, lactobacilli and acid-producing streptococci are the forms commonly believed to be implicated in decalcification of human teeth. However, these organisms are regularly found in the mouths of caries-free rats and if they are involved in experimental rat-caries their activities must be dependent upon other not well understood factors. The present investigation was made with animals used by Dr. B. F. Miller in a study of the inhibition of rat-caries and cultures were taken with his kind coöperation. Material from the surfaces of molar teeth of 60 young rats was cultured aërobically, at the beginning of the diet periods and again after 7 and 13 weeks, on Kulp's agar, Jay's broth, blood-agar, and brom-cresol-green serum-dextrose agar. The methods were not quantitative but all samples were handled in the same way and the results therefore have comparative value. In the first culture-period streptococci comprised from half to three-fourths of the colonies obtained. They were in general about equally divided between α, β and γ types and in most cases about twice as many were acidogenic as non-acidogenic. The remaining organisms were largely lactobacilli, staphylococci, and micrococci. Other forms were encountered less frequently and usually in small numbers. From Jay's and modified Kulp's media lactobacilli were recovered in all cases but since these media tend to suppress organisms that are not aciduric, comparative counts of acidogenic organisms were confined to indicator-plates. The studies of Miller have shown a high incidence of cavities in animals on a caries-producing diet, fewer lesions in a group receiving this diet together with calcium fluoride and little or no caries in groups with added sodium fluoride or iodoacetic acid.

Inhibition of Experimental Dental Caries in the Rat by Fluoride and Iodoacetic Acid

SummarySodium fluoride and iodoacteic acid added to a caries-producing diet fed to albino rats diminished greatly the incidence of carious lesions in the molar teeth.

Failures to Produce Experimental Dental Caries in the White Rat with High Carbo-hydrate Diet and Bacillus Acidophilus or with Vitamin D Deficiency

Failures to Produce Experimental Dental Caries in the White Rat with High Carbo-hydrate Diet and Bacillus Acidophilus or with Vitamin D Deficiency

The Histopathology of Experimental Molar Caries in Rats

The Histopathology of Experimental Molar Caries in Rats