Effect of prenatal, preeruptive, and posteruptive strontium administration on dental caries in hamster molars

Patient-applied treatment of dentinal hypersensitivity

This article reviews the evidence regarding the effectiveness of various patient-applied interventions for dentinal hypersensitivity. Self-applied treatments are popular because they are both economical and easy to use. The disadvantages include compliance, difficulty to deliver to specific sites, slow onset of action, and the requirement for continuous use. Conflicting research findings make it difficult for the practitioner to determine which self-applied product to advise patients to use. There are a number of issues that have plagued research in this area, including the lack of standardization of stimulus testing and inadequate sample size. The evidence is insufficient to permit the development of evidence-based guidelines for the treatment of dentinal hypersensitivity.

Dental caries and strontium concentration in drinking water and surface enamel

We investigated the possible cariostatic effect of strontium in the absence of effective amounts of fluoride by relating the DMFT index of the population to the strontium and fluoride concentrations in drinking water and enamel surfaces. The epidemiological survey was conducted in two neighboring districts in the northwest part of Greece, involving 582 children ranging in age from 11 to 14. The average DMFT values were 5.26 in the high-strontium (2.9-7 ppm Sr) area and 6.95 in the low-strontium (0.2-1.3 ppm Sr) area, while fluoride was low (less than 0.06 ppm) in both districts. Further, the average strontium concentration in surface enamel was higher in the high-strontium area.

Combined effect of trace elements and fluoride on caries: changes over ten years in northwest Ohio (U.S.A.)

Dental caries examinations were carried out in an area of low caries prevalence, ascribed to a combined effect of fluoride and other trace elements. Repeat examinations in 1978 on lifelong resident children aged from 12 to 14 yr showed caries distribution patterns to be essentially the same as those found in a previous study in 1968. Some changes in DMFS scores had occurred, which were associated with changes in the strontium content of the drinking water; low caries levels were significantly associated with high strontium concentrations.

EDTA enhancement of strontium uptake by intact human enamel

The aim of this research was to study the effect of EDTA on the strontium uptake by intact tooth enamel. EDTA did not significantly affect the strontium uptake in an acid medium of pH 4.5. However, it caused a sharp rise in strontium uptake at pH 6.0. At such a pH, the stability constants of the Ca-EDTA complex are approaching a maximal value, and as a result of it a significant dissolution of the surface enamel, accompanied by a highly effective increase of the contact area for strontium uptake, is taking place. In all the experiments, treatment with strontium solution resulted in a decrease of the solubility and dissolution rate of enamel in an acidic environment. The resistance of enamel to acid attack was proportional to the quantity of absorbed strontium, reaching maximal values after treatment with strontium solutions in 10(-2) M EDTA at pH 6.0.

Effects of strontium administration on rat molar morphology

Strontium at concentrations of 0, 50 and 150 mg/l was given to rats during pregnancy and to the pups during a pre- and post-weaning period. Measurements were made on first and second mandibular molars to assess the morphology of tooth and fissure dimensions, and enamel and dentine thickness. A significant increase in horizontal and vertical dentine thickness was associated with a level of 50 mg Sr/l, a concentration previously found to be associated with decreased caries prevalence in rats.

In vivo and in vitro study of 90Sr in developing rat molar enamel

The uptake patterns of 90Sr in developing rat molar enamel were studied in vivo and in vitro. Autoradiographic methods were used that preclude loss or translocation of tracers associated with water-soluble compounds in the sections. In eight-day-old rats injected with the tracer, 90Sr uptake in the enamel was significantly less than for dentin and bone, particularly at early sacrifice times. The uptake pattern of 90Sr was somewhat different from that previously observed for 45Ca. The in vitro experiments indicated that the viable intact enamel organ limits uptake of 90Sr by enamel in both the secretory and maturation phases of enamel formation.

Relationship of strontium in drinking water and surface enamel

The Sr content of surface enamel of 233 teeth from nine communities was related to drinking water Sr concentrations. These water concentrations ranged from 0.02 microgram/ml to 33.9 microgram/ml. The relationship between enamel concentrations and water concentrations was linear for water concentrations less than 10 microgram/ml Sr, but leveled off at approximately 300 microgram/gm Sr in the enamel for communities with greater than 10 microgram/ml Sr in drinking water. Binding of Sr to components in the oral environment is proposed as an explanation of this effect.