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Biomedical subjects

S R Grobler

Publications and source records attributed to S R Grobler.

At least 55 records · Page 3Linked to original sources
PubMed1988

Fluoride distribution in the enamel of the mesio-lingual cusps of pairs of erupted and unerupted third molars of man with a low fluoride background.

The enamel fluoride concentrations at different depths were determined at 5 different sites on the mesio-lingual cusps of 16 pairs of erupted and unerupted third molars. Six successive acid etchings were done on each of the 5 sites. The 16 subjects (18 to 33 years) were living continuously since birth in a low fluoride area (F less than 0.10 ppm). They did not take any systemic fluoride since birth nor did they practise any other anti-caries fluoride program than brushing their teeth once or twice a day with fluoride-containing dentrifrices with about 1,000 ppm fluoride. The fluoride level in the etch solution was measured with the use of an adapted fluoride selective electrode. Statistically significant differences (p less than 0.05) were found in the mean etch depth between the erupted and unerupted molars, to a depth of approximately 5 micron. The mean enamel fluoride concentrations of the erupted and unerupted molars also differed significantly to a depth of approximately 5 micron. There was no influence of fluoride from the oral environment on enamel levels of approximately 10 micron and deeper. Over an exposure period of 1 to 16 years, sixty percent more enamel fluoride (at a depth of approximately 2 micron) was found in the erupted enamel relative to the unerupted enamel (with a low background fluoride) as a result of tooth brushing with fluoride-containing dentifrices. More enamel fluoride was found near the incisal edge than near the cervical margin of 14 of the 16 subjects independently of the age of the subjects.

Acid Etching, Dental↗
PubMed1987

Unusually high circumpulpal lead concentrations as valid evidence of lead intoxication.

A case is reported of a 59-year-old male who had been employed continuously as a motor technician for 32 years. During the latter period of his employment he gradually developed a number of the signs and symptoms typically manifested by persons suffering from lead intoxication. Five years after the termination of his employment, the lead content in the circumpulpal dentine of 2 of his teeth was determined and found to be more than 7 times higher than that of the controls. Thus, the probability of lead intoxication is supported very strongly.

Dentin↗
PubMed1986

Enamel-fluoride levels in deciduous and permanent teeth of children in high, medium and low fluoride areas.

The surface enamel-fluoride concentration (approximately 4 microns) of both deciduous and permanent teeth of the central upper incisors were determined in 5-7 and 11-13-year-old children, who were born and bred in isolated areas with naturally high (3.7 parts/10(6)), medium (0.6 parts/10(6)) and low (less than 0.1 parts/10(6)) fluoride in the drinking water. Samples were taken in vivo by an acid-etch procedure and fluoride levels measured with an adapted fluoride-ion selective electrode. There were no significant differences in the fluoride concentrations or between etching depths between boys and girls, none between the contralateral incisors nor between the etching depths of deciduous and permanent teeth either in a single area or the three different ones. However, a highly-significant difference (p less than 0.01) was found in the enamel fluoride levels between the deciduous and permanent teeth in a fluoride area or among the three different fluoride areas. The ratio of the mean enamel fluoride concentration of permanent teeth to that of deciduous teeth increased with rise in fluoride in the drinking water. It is concluded that the different lengths of time, during which the crowns of deciduous and permanent incisor mineralize, contribute to this differing ratio.

Adolescent↗
PubMed1986

Surface enamel fluoride concentrations of different types of human teeth in a high- and near-optimal-fluoride area.

The surface enamel (approximately 4 micron) fluoride concentrations of different tooth types (11, 21, 22, 23, 24) were determined in 12-13-year-old children who were life-long residents in a naturally high (3.70 ppm) and in a near optimal (0.62 ppm) fluoride area. Enamel biopsies were taken by means of an acid-etch procedure, and the fluoride levels were measured with an adapted fluoride-ion-selective electrode. The enamel fluoride concentrations were related to the fluoride levels of the drinking water, and it appeared that the enamel fluoride concentrations of the different tooth types (except for the pre-molars) were associated with the length of the pre-eruptive period. In general, for both areas, the mean enamel fluoride concentrations increased from the central incisor to the lateral incisor and were found to be the highest in the canine, while the mean fluoride content of the first pre-molar nearly equaled that of the central incisor. No statistically significant differences (p greater than 0.05) were found between the enamel fluoride concentrations of the different tooth types or the etching depths, from different sexes.

Acid Etching, Dental↗
PubMed1985

Blood lead levels in motor mechanics.

The whole-blood lead levels of a group of motor mechanics in the Cape Peninsula were determined. Blood was analysed using a graphite furnace atomic absorption spectrometer. The mean whole-blood lead levels of the motor mechanics and of urban controls were 28,4 micrograms/dl and 9,7 micrograms/dl respectively, and comparison of these with that of a group from an unpolluted rural area (3,4 micrograms/dl) revealed highly significant differences.

Adult↗
PubMed1985

Blood lead levels in a remote, unpolluted rural area in South Africa.

The whole-blood lead levels of 14-16-year-olds in a remote, unpolluted rural area (Wupperthal, north-western Cape Province) were determined. Graphite-furnace atomic absorption spectrometry was used to analyse lead levels. The mean whole-blood lead level was found to be 3,4 micrograms/dl. This value should also be considered to be representative of the natural 'background' whole-blood lead level of South Africans.

Adolescent↗
PubMed1985

Lead in teeth of weanling rats received via the maternal drinking water.

Pregnant rats were dosed with 0, 3 or 10 parts/10(6) lead (as acetate) in their drinking water, during pregnancy and during lactation until 21 days post partum. The litters were killed at the age of 21 days and the incisors, first, second and third molars analysed for lead by atomic absorption spectrophotometry. The findings confirmed that even at low concentrations lead has an affinity for hard tissues. The mean lead levels of the teeth of the three groups differed at the 1 per cent level. Pb levels of the first and second molars and the incisors also differed at the 1 per cent level. No significant differences between the four types of teeth within a group could be demonstrated. The no-effect level of Pb administered in drinking water, to the mother during lactation, and during pregnancy, was lower than 3 parts/10(6).

Animals↗
PubMed1985

Lead levels in circumpulpal dentine of children from different geographic areas.

Lead pollution can produce a variety of effects on the human body. Shed deciduous teeth were collected from primary school children in urban, suburban and rural areas in South Africa. The lead content was determined through atomic-absorption spectrophotometry. The average circumpulpal dentine lead levels in the urban, suburban and rural samples are 74.5, 44.3 and 26.5 parts/10(6) respectively. From the results it is clear that this most inner part of dentine (approximately 300 microns thick) can concentrate up to five times more lead than the total dentine. Comparison of the lead ratio of circumpulpal dentine to that of the total dentine for the different areas demonstrates the greatest tendency for preferential lead accumulation in the circumpulpal dentine. Lead analysis of circumpulpal dentine revealed that in deciduous teeth the lead level was related to the degree of industrialization.

Child↗
PubMed1984

Chemical analysis of cool drinks and pure fruit juices--some clinical implications.

The pH of cool drinks and fruit juices is very low and ranges from 2,4 (Pepsi Cola) to 3,7 (fresh orange juice). The osmotic concentration of most cool drinks and fruit juices is considerably higher than that of blood and, with the exception of Isotonic Game, ranges from 430 mOsm/kg (Coca Cola) to 1 297 mOsm/kg (Liquifruit Grape). Glucose, fructose and sucrose contribute from 72% to 98% of the osmotically active particles in cool drinks and fruit juices and their high carbohydrate content causes concern about substrates for oral bacteria to produce acid as well as daily energy intake. The sodium (Na), potassium (K), calcium (Ca) and phosphorus (P) content of cool drinks is low although K and P may contribute significantly to dietary intake when most fruit juices are consumed. K is virtually absent in Coca Cola and its use in replacing lost minerals, e.g. in infantile gastro-enteritis, is disputed. The relatively high levels of K and P in fruit juices could be harmful to patients suffering from chronic uraemia. The selected cool drinks and fruit juices analysed contain very little Na and should not pose problems to hypertensive patients.

Beverages↗
PubMed1983

lead levels in deciduous teeth of children from selected urban areas in the Cape Peninsula.

The lead levels in shed deciduous teeth of children from two selected urban regions in the Cape Peninsula were compared. The average levels in the teeth of children living in the vicinity of two large industrial plants were: whole teeth 20,419 ppm, enamel 10,952 ppm, and dentine 22,733 ppm. The lead levels in teeth from children living in the vicinity of light industries were: whole teeth 16,556 ppm, enamel 2,919 ppm, and dentine 19,926 ppm. These differences were significant at the 1% level (teeth and enamel) and 5% level (dentine).

Child↗