Biomedical subjects

M V Stack

Publications and source records attributed to M V Stack.

11 recordsLinked to original sources

PubMed1989

Effects of fluoride and/or trace elements on enamel solubility.

Various studies have shown that the solubility of dental enamel can be reduced by exposing it to metal ions in the presence of fluoride. The purpose of this study was to determine the effects of various trace metal ions at two concentrations on dental enamel solubility and fluoride uptake. The solubilities of the enamel surfaces and their fluoride concentrations were first determined. Atypical teeth were discarded. Blocks of enamel were then divided into groups of five and solutions of salts of aluminium, strontium, titanium, molybdenum and vanadium followed by fluoride (4,000 ppm) were applied. Two successive layers were then etched off, using perchloric acid. Fluoride in the enamel was determined using an ion-specific electrode system. Calcium was determined by atomic absorption spectrophotometry. The values obtained were used to calculate the thicknesses of the layers removed. The results showed that combined application of aluminium and fluoride led to a marked reduction in solubility of enamel (p less than 0.001). Application of strontium (0.01 M) and fluoride also led to a significant reduction in enamel solubility (p less than 0.01). Pretreatment with titanium solution (both concentrations), aluminium or molybdenum solutions (higher concentrations) increased fluoride uptake in comparison with the control group. Statistically significant increase in fluoride uptake was seen only in those enamels treated with titanium solution at higher concentration when compared with those treated with fluoride alone.

Aluminum↗

PubMed1986

Superficial fluoride levels and response to in-vitro caries-like lesion induction of enamel from Bristol (U.K.) and Birmingham (U.K.) human deciduous teeth.

Surface enamel fluoride levels were measured in deciduous canine teeth from Bristol, with non-fluoridated water supplies, and Birmingham, with fluoridated water supplies. Three populations studied were from Bristol (teeth shed before 1960), Bristol (after 1975) and Birmingham (after 1975). Up to 75 micron from the enamel surface, fluoride concentrations of post-1975 Bristol and Birmingham teeth were, respectively, X 1.3 and 3.4 greater than those of pre-1960 Bristol teeth. The increase in the Bristol teeth is presumably due mainly to the increased use of fluoride-containing toothpastes, that in Birmingham to fluoridated water plus the use of fluoride toothpastes. No difference in the rates of penetration into enamel of acid-gel induced, caries-like lesions were found between the two Bristol populations; Birmingham teeth showed a reduction of 10 per cent in penetration rate. It is suggested that raised fluoride levels in surface enamel do not reduce solubility sufficiently to account, by themselves, for the recent nationwide marked reduction in caries in children. Possibly, the raising of plaque fluoride levels is a more important factor, affecting demineralization, remineralization and bacterial activity.

Acid Etching, Dental↗

PubMed1985

Postnatal changes in size, morphology and weight of developing postnatal deciduous anterior teeth.

The present investigation is concerned with the postnatal changes in size, morphology and weight of anterior deciduous teeth (maxillary and mandibular central and lateral incisors and canines) in infants aged 0-46 weeks. Relating tooth weight and height to the age of the infant revealed the time at which each tooth achieves its maximum crown height and root formation begins, the rate of root elongation and, in the case of the canine teeth, the postnatal rate of crown elongation.

Aging↗

PubMed1978

Discrimination between oral streptococci by pyrolysis gas-liquid chromatography.

Washed organisms, including strains of Streptococcus mitior, S. mutans, and S. sanguis, were examined by curie-point pyrolysis gas-liquid chromatography. A linear discriminant function based upon three items from the output data was adequate for segregating the strains according to species. Strains with intermediate properties were also encountered. Sources of variability in cultures were evaluated, chromatographic performance was maintained throughout the investigation, and matching performance from a duplicate pair of chromatographic columns was demonstrated.

Dental Plaque↗

PubMed1976