Eleanor J. Edmonds

Effect of Rice Hulls and Other Seed Hulls on Dental Caries Production in the Cotton Rat

While studying natural diets which were cariogenic to the cotton rat, Constant, Sievert, Phillips, and Elvehjem1 found that the degree of dental caries produced by an oatmeal diet was sharply decreased by the inclusion of finely ground oat hulls in the diet. The protective effect was greater at the 25 per cent level than at the 12.5 per cent level. Later work by Taketa and Phillips2 demonstrated that oat hulls were also protective in a semipurified diet at both 25 and 10 per cent levels. These workers furnished evidence suggesting that the protective effect was due neither to a brushing or abrasive action by the hulls nor to a dilution of the cariogenic diet by the hulls. They also verified an earlier observation by Constant et al.1 that the ash portion of the hulls was not anticariogenic. Jenkins and Phillips3 showed that the crude fiber, hemicellulose, and lignin fractions of the hulls were devoid of anticariogenic activity. Taketa and Phillips2 found that the greatest activity was located in an ethanol-soluble fraction of the hulls, which comprised less than 5 per cent of their weight. Some activity remained in the residue; however, later studies4 showed that extraction with ammoniacal ethanol removed activity that was not removed by ethanol alone. The activity in the ethanol extract not only was effective in the inhibition of dental caries but was also capable of inhibiting the growth of organisms isolated from the carious cotton rat tooth.5 This observation, coupled with the fact that a pure culture of Lactobacillus acidophilus var. Farr was inhibited by the extracted solids, indicated that the anticariogenic activity of oat hulls was related to an alteration in the oral flora of the cotton rat. Using L. acidophilus as an assay organism for oat-hull anticariogenic factors, Taketa and Phillips5 found the active factors to be acidic in nature and perhaps to be certain phenolic acids and palmitic acid. Madsen4 assayed other seed hulls for their anticariogenic activity by feeding them in an oatmeal diet at the 25 per cent level. It was found that, in addition to oat hulls, the hulls of rice and peanuts were also effective and reduced the incidence of caries by about 75 per cent; the hulls of cottonseed and barley reduced the incidence by about 35 per cent. Madsen also demonstrated that the acidic fraction prepared from ethanol extracts of these hulls was effective as a growth inhibitor of L. acidophilus var. Farr. Subsequent studies demonstrated that oat hulls were also anticariogenic in the diet of the albino rat. Madsen4 found them to be anticariogenic when fed in a semipurified diet to the Harvard strain of caries-susceptible rats. Buttner and Muhler6 demonstrated

Effect of Rate of Gland Function on Parotid Saliva Fluoride Concentration in the Human

A series of experiments were carried out to determine the effect of the rate of gland function on parotid saliva fluoride levels in the human. Means for fluoride for stimulated parotid saliva ranged f

Prolonged Effect on Caries of Short-Term Feeding of Rice Hulls to Cotton Rats

In a recent review of caries-inhibiting agents, Shawl has described and evaluated the procedures developed for experimental caries research. In general, it is useful to evaluate the anticariogenicity of a substance by incorporating it into a cariogenic diet that is fed to weanling caries-susceptible rodents. After a sufficient time for caries development in the control group, the caries inhibition by the test substance is measured. A compilation by Hein2 of a large number of assays for anticariogenic agents has indicated that, in most cases, the test substance was fed for the entire experimental period of about 100 days or more. In other studies animals were fed the test substance for a prolonged period, although for less than the experimental period. McClure3 has found a prolonged reduction in caries when he fed 100 ppm of fluoride to 40-, 100-, and 200-day-old rats for 85, 60, and 40 days, respectively, and followed this procedure by a cariogenic diet for 100 days. Keyes4 has recently described a new method for assaying caries-inhibiting agents. In his procedure, caries was developed in weanling hamsters until they were 39 days of age. They were then fed penicillin in the diet for 54 days. Penicillin was then removed, and the cariogenic diet was fed for an additional 50 days. Since the third molars had erupted between 35 and 40 days of age, all three molars received a prolonged treatment with the test substance. Remaining largely unexplored in experimental caries assays has been the possibility that it may not be necessary to feed the test material for the entire experimental period or even for a prolonged portion of it. If short-term feeding were effective in the animal assay employed, the opportunity of testing the anticariogenicity of scarce, as well as toxic, materials would be enhanced. Moreover, the ability of a material to exert a prolonged protective effect would be a useful criterion for the selection of anticariogenic materials for clinical trials. Successful short-term feeding trials have been reported. Fitzgerald, Jordan, and Poole5 have found that only 13 days of penicillin feeding, 1 day per week, reduced caries scores of rats fed a cariogenic diet for 13 weeks. Marthaler, Konig, and Muhlemann6 have found that rats exposed to stannous fluoride for 8 days were protected during subsequent feeding of the cariogenic diet. They have found that the pretreatment exerted a protective effect for 25 days. They did not determine the protective effect for longer periods, since their primary objective was to develop a short-term assay. In the present study a long experimental period of 98 days was used, but the test substance was included in the cariogenic diet for only 10 days. By feeding the test

Effect of fluoride dosage on human parotid saliva fluoride levels

Abstract Parotid fluid and urine F levels were studied in healthy young adult males receiving either 0, 1.0, 3.0, 5.0 or 10.0 mg of F by mouth. Urinary F excretion rates were virtually a linear function of size of dose. For the different doses of F, urine F recovery rates ranged from 20.0 to 31.3 per cent (mean = 25.3 per cent). For saliva F, dosage with 1.0 mg did not significantly change the placebo pattern. The 3.0 mg dose increased saliva F significantly in the 20–30 min sample. The 5.0 mg dose produced this change in the 10–20 min sample, and the 10 mg dose was effective in the 0–10 min specimen. Peak salivary F concentrations occurred at about 40–50 min after dosage and declines, with slopes a function of dose level, ensued thereafter. Even after 4 hr, saliva F levels for the 3 higher dose groups remained significantly elevated. There was a suggestion of carry-over effect in that pre-dose control saliva F levels each morning were significantly higher when subjects were receiving 3.0, 5.0 or 10.0 mg than when the dosage level was 1.0 mg.

Prolonged effect on caries of short term fluoride treatment—I

Abstract Sodium fluoride fed to weanling cotton rats for only 2 days on the 12–13 days of age significantly reduced the caries scores observed at 40 days of age. Fluoride at 45 p.p.m. had this effect when fed in either natural or semipurified cariogenic diets. The newly-erupted first molars were the only teeth protected significantly by early fluoride treatment. These experiments and previous studies using cotton rats demonstrated that newly-erupted teeth are readily influenced by short-term exposures to anticariogenic factors. The 12 day weanling cotton rat was found to he a valuable tool for studying such relationships.

Fluoride Levels in Human Parotid Saliva Following Ingestion of Fluoride Compounds of Varying Solubility

Healthy dental students received oral doses of 10.0 mg F daily in the form of compounds of widely varying solubilities. Parotid saliva F concentration and urinary F excretion were highest with NaF, Na 2 PO 3 F, and SnF 2 , lowest with CaF 2 , and intermediate with AlF 3 . Solubility of the ingested fluoride compound was a controlling factor in the amount of F excreted in the urine, the peak F concentration reached in parotid saliva, and the duration of a significant elevation in salivary F.

Topical applications of stannous fluoride: choice of concentration and duration of treatment

Abstract The capacity of 10, 0·4 and 0·1 per cent SnF 2 solutions, topically applied for 4, 2 or 1 minute or 30 or 15 seconds, to reduce the solubility of enamel, was evaluated by measuring the amount of phosphorus withdrawn from enamel surfaces by lactic acid before and after treatment. For treatment periods of 1 minute or longer, there was no significant difference in the performance of 10 and 0·4 per cent SnF 2 solutions. With treatment periods of 15 and 30 seconds the 10 per cent solution was more effective. Solutions containing only 0·1 per cent SnF 2 , suggested for use as a mouthrinse at home, were less effective than the more concentrated solutions, but 1- and 2-minute treatments with this concentration gave solubility-reduction figures of 42·2 and 47 per cent respectively. The possibility of use on a very frequent basis makes these figures particularly impressive. The results of this study indicate that quadrant-by-quadrant topical treatments with high concentrations of stannous fluoride may be adequately replaced by mouthrinsing with solutions of much lower concentration. Thus, frequent applications of low concentration SnF 2 preparations at home by the patient may offer a valuable degree of protection, particularly to the patient with a high caries risk.

Failure of environmental lighting to influence dental caries rate.

Summary Two experiments involving lit-termate cotton rats were conducted to determine the effect of cool-white fluorescent versus artificial sunlight environments on caries incidence. There were no significant differences in either the incidence or extent of caries associated with the different types of lighting. This contradicts our previous observations (1) with this species using identical experimentation and calls for a retraction. It is suggested that the difference is due primarily to the application of an inappropriate statistical approach in the earlier work.

Dental Caries Protection in Cotton Rats with Sodium Fluoride Solution

The ability to wean cotton rats satisfactorily at 12 days of age (K. 0. Madsen and E. J. Edmonds, J. dent. Res., 42:867-73, 1963) has provided a convenient means for studying the influence of dietary factors on dental caries when they are provided at various stages of molar tooth development. Sodium fluoride, incorporated in an oatmeal cariogenic diet and fed for only 2-3 days immediately after the eruption of the respective molars, has been found to reduce dental caries significantly (K. 0. Madsen and E. J. Edmonds, Fed. Proc., 22:553, 1963). Fluoride, fed at 45 ppm in the diet from the twelfth through the fourteenth day, significantly protected first molars, which erupt from 7 to 12 days of age, but had no effect on second molars, which erupt from 12 to 20 days of age. With an ad libitum feeding regimen, it is difficult to determine accurately the amount of fluoride ingested by the rats during the 3-day experimental period. The purpose of the present study was to determine whether fluoride administered in controlled amounts of 0.1 per cent solution for short periods would reduce dental caries as it does when incorporated in the diet fed ad libitum. The rats were weaned at 12 days of age, and littermates were divided into 2 groups. Both groups were housed in individual wire cages and provided with water and the oatmeal cariogenic diet ad libitum. The control group was supplemented with 2 drops of distilled water every hour 8 times daily for 3 days after weaning. The experimental group was supplemented in the same manner with 2 drops (0.1 ml.) of 0.1 per cent NaF. This amount of NaF solution provided a measured amount of fluoride about equal to that estimated to be normally consumed daily in a diet containing 45 ppm fluoride. The rats were sacrificed at 40 days of age and the teeth scored for fissure caries (J. H. Shaw, B. S. Schweigert, J. M. McIntire, C. A. Elvehjem, and P. H. Phillips, J. Nutr., 28:333-45, 1944). Frequent handling of the newly weaned animals during the experimental period did not affect food or water consumption or final body weights. Also, no noticeable differences in these parameters were observed between the controls and the group receiving fluoride. The table shows the caries scores.

Short assay periods and restricted feeding procedures in caries assays with cotton rats

Abstract Three varieties of rice hulls were assayed under equivalent conditions by either long, 98-day assays or by short, 28-day assays. In the long assays, 18-day-old weanlings were used, and caries scores were evaluated in all three molar teeth. In the short assays, 12-day-old weanlings were used, and caries was observed in first and second molars. A mixture of three rice hull varieties was tested in two 18-day assays under the same conditions as the 28-day assays. All assays readily detected anticariogenicity in the hull samples. It was concluded that for detecting rice hull activity, assays longer than 18 days and inclusion of third molar scores were unnecessary. The usefulness of assays employing only short preliminary feeding of rice hulls was also studied. An initial, 3-day feeding of hulls did not influence caries scores measured 15 days later at 30 days of age, but 18 days of hulls significantly decreased scores at 30 days and for as long as 30 days after feeding hulls was discontinued. These studies confirmed the advantages of such assays. They allow a substance to be evaluated for its ability to exert prolonged protection. If extended to 50 days of age or longer, they permit an evaluation of anticariogenic effects on unerupted teeth. The assay periods may be short if the agent being tested is sufficiently potent to protect after a few days of feeding. Sensitivity to short feedings can be increased by controlling dietary sucrose. Evidence reviewed indicated that the short assays and the restricted feeding procedures described would be useful for evaluating agents other than rice hulls and that the results of the assays would be of significance in caries studies other than those using cotton rats.