Sheila A. Mundorff

Enamel Dissolution: II. Action of Titanium Tetrafluoride

Mechanisms by which titanium tetrafluoride (TiF4) reduces enamel solubility were investigated. An association was found between solubility reduction and the formation of a glaze on the enamel surface. Also, TiF4treated enamel had higher levels of fluoride than enamel treated with acidulated phosphate-sodium fluoride. Solubility reductions and fluoride levels decreased slightly with washing but after 48 hours the fluoride level was still 60% of the maximum, and solubility reductions ranged between 64 and 70%.

Enamel Demineralization by Snack Foods

The amount of enamel destroyed by salivary fermentation of snack foods and confections was not dependent on their sugar content; starch, flavoring agents, and other components also played a part. Most enamel destruction was produced by fruit-flavored candies in which the inherent acid or high sugar concentration or both inhibited bacterial fermentation.

Enamel Dissolution: I. Effects of Various Agents and Titanium Tetrafluoride

By comparing phosphorus loss from enamel windows during successive exposures in acetic acid buffer, measurements were made of the effects of a number of uncommon fluoride and nonfluoride compounds on enamel dissolution. Acidulated ytterbium chloride and the tetrafluorides of titanium, zirconium, and hafnium gave much more lasting protection against the action of acid than did the fluorides commonly used for caries prophylaxis.

Correlations between Numbers of Microf lora in Plaque and Saliva

An epidemiologic investigation to reliably identify caries-susceptible subjects by microbiological and chemical assessment of plaque and saliva is currently in progress. As part of that study, the numerical relationships of mutans streptococci, lactobacilli and total viable microflora in plaque and saliva among 12- to 15-year-old children in a fluoridated community were determined. Paraffin-stimulated whole saliva and pooled dental plaque were collected. Each sample was suspended in reduced transport fluid, chilled on ice, and assayed. The bivariate normal distribution was found to be a suitable model for the distribution of the pairs [numbers of bacteria in plaque (log10), numbers of bacteria in saliva (log10)]. Statistically significant positive correlations were found between numbers of mutans streptococci in plaque and saliva, and between lactobacilli in plaque and saliva.

Oral food clearance and the pH of plaque and saliva

Carbohydrate clearance, plaque pH, and saliva pH resulting from eating foods containing high levels of sugar or starch were measured in the same experimental runs on the same test subjects. Foods with a higher content of sugar were removed more rapidly and depressed the pH of the plaque for a shorter time than did starchy foods containing less sugar. This finding suggests that retention of food in the mouth may be as important an indicator of its cariogenic potential as is the level of the pH it produces in plaque.

Preliminary Studies on Calcium Lactate as an Anticaries Food Additive

Enamel dissolution, Orofax and rat caries studies were carried out to assess the effects of calcium lactate in reducing the cariogenicity of four commercially used candies. When used at the 5% level, calcium lactate was effective in reducing enamel dissolution by as much as 43% in fermenting candy-saliva mixtures. In Orofax studies it reduced the amount of in vitro caries by as much as 87%. In a rat caries study, a test group fed a chocolate caramel candy containing 1.5% calcium lactate produced reductions of 38 and 17% in number and 47 and 31% in severity of smooth surface (buccolingual) and sulcal lesions, respectively, as compared to a control group fed the same candy without additive. These findings plus the fact that calcium lactate is a tasteless, nontoxic chemical compound, commonly used in a number of food products, all indicate that calcium lactate my be considered an effective anticaries food additive.

Effect of Fluoridated Sucrose on Rat Caries

The present study was designed to test the effect of frequent pulses of low fluoride levels on rat caries when supplied in a standardized cariogenic rat diet containing 67% sucrose (MIT-200). The test diets were variants of Diet MIT-200 in which the sucrose component had been fluoridated with NaF solution resulting in total concentrations of 0 (control), 2, 3, 5, 10, or 20 ppm fluoride in the final diets. Rats received one of the test lots 17 times daily in a programmed feeding machine beginning at age 22 days, and were inoculated with Streptococcus mutans at age 23, 24, and 25 days. After 5 weeks, the rats were sacrificed and their mandibular molars scored for number and severity of sulcal, buccolingual, and proximal caries. Frequent daily pulses of as little as 2 ppm fluoride in dietary sucrose were effective in significantly (p less than 0.01) reducing buccolingual rat caries.

Enamel Demineralization Tests with Some Standard Foods and Candies

To indicate the cariogenic potential of some standard foods and confections, their ability to demineralize powdered enamel or enamel sections was tested by incubation with mouth organisms in saliva or plaque. With a few exceptions, the amounts of demineralization produced by the tested substrates in either a closed or flowing system fell within relatively narrow ranges.

Inhibitory Effect of Barium on Caries Formation in Rats

The aim of this investigation was to study the effect of barium and fluoride in drinking water on caries formation in rats. Sprague-Dawley rats were fed a cariogenic diet (MIT-200) 17 times daily in a König-Hofer programmed feeding machine for 37 days. Drinking water containing barium (0, 50 or 100 ppm) and fluoride (0 or 10 ppm) was available ad libitum. Rats to whose water was added 50 ppm barium had significant reductions in the mean severity of both buccolingual lesions and sulcal lesions compared with those rats whose water contained no barium. As expected, F at 10 ppm in the drinking water significantly reduced caries severity but this F effect was independent of the barium effect. This suggests that the inhibitory effects of barium and fluoride at these levels are additive and operate by separate mechanisms.

Comparison of essential nutrient supplement effects on rat growth and dental caries.

Rat weight gains and dental caries, in relation to salivary gland weights, flow rates and microbial data, were compared in three groups of sucrose-fed rats, provided with NCP2, NAV456 (1:1.5) or MIT-2