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Biomedical subjects

O Fejerskov

Publications and source records attributed to O Fejerskov.

At least 127 records · Page 7Linked to original sources
PubMed1986

Posteruptive tooth age and severity of dental fluorosis in Kenya.

The purpose of the present study was to assess whether the degree of severity of enamel changes in a population exhibiting rather severe dental fluorosis may be related to posteruptive tooth age and to describe the clinical manifestations of the enamel destructions. All permanent teeth in 102 children aged 10-15 yr who were born and reared in a 2 ppm fluoride area of Kenya were examined for dental fluorosis using the TF-Index. Clinically, at time of eruption all teeth appeared chalky white, but already prior to coming into occlusion discrete pits had formed. A variety of more extensive damages to the surface enamel was found in teeth already in occlusion. In particular, the maxillary incisors exhibited extensive artificial attrition for cosmetic reasons, which make these teeth unreliable for accurate scoring of severity in the present population. An analysis of the proportion of teeth exhibiting TFI-scores 4+, 5+ and 6+ showed that children aged 13-15 yr had a significantly greater proportion of teeth with TFI-scores greater than or equal to 6 compared to children aged 10-12 yr (Wilcoxon, P less than 0.0001). This finding is unlikely to be a result of different fluoride exposures in the two age groups and indicates that even several years after eruption there is a trend towards an increasing severity of enamel surface destructions in children exhibiting pronounced degrees of subsurface enamel hypomineralization at time of eruption.

Adolescent↗
PubMed1986

Dental fluorosis in an area of Kenya with 2 ppm fluoride in the drinking water.

We examined 102 children born and reared in an area of rural Kenya with 2 ppm fluoride in the drinking water for dental fluorosis, using the index developed by Thylstrup and Fejerskov (1978). The prevalence of dental fluorosis was 100%, 92% of all teeth exhibited a TFI score of 4 or higher, and 50% of the children had pitting or more severe enamel damage in at least half the teeth present. The fluorotic changes showed a high degree of bilateral symmetry. The intra-oral distribution of the changes corresponded to the pattern of fluoride-induced enamel changes reported by other investigators in high-fluoride areas. The high prevalence and severity of dental fluorosis in a 2-ppm-fluoride area is in accordance with recent observations on dental fluorosis being very prevalent in Kenya, even in low-fluoride areas (less than 1 ppm F). We are presently investigating the possible variables which may explain this unexpected susceptibility of large populations in Eastern Africa to fluorosis from exposure to low levels of fluoride.

Adolescent↗
PubMed1986

Dental fluorosis developed in post-secretory enamel.

The aim of this study was to test whether dental fluorosis can be produced by administration of chronic doses of fluoride during only the post-secretory stage of enamel mineralization. Eight control and eight experimental pigs matched by weight and litter were fed a low-fluoride diet (less than 0.05 mg F-/kg b.w. daily) from weaning to slaughter at 14 months. The test group received an oral dose of 2 mg F-/kg b.w. per day from 8 months of age. Lower fourth pre-molars were at the post-secretory stage at the start of fluoride administration (confirmed by tetracycline marker) and were just erupting at slaughter. All of the fourth pre-molar teeth from the test group developed diffuse enamel hypomineralization indistinguishable from human fluorosis. No such lesions were seen in any of the teeth from the control animals. It was concluded that enamel fluorosis may be caused by fluoride exposure in the maturation phase only. The pathogenic mechanism may be an effect either on the selective loss of protein or on the influx of mineral, both of which occur during the post-secretory or maturation stage of enamel formation.

Amelogenesis↗
PubMed1985

Prevalence of dental fluorosis after fluoride-gel treatments in a low-fluoride area.

The goal of the present investigation was to study whether periodic use of fluoride-gel treatments resulted in an increased prevalence of dental fluorosis. 269 children, from 14 to 16 years of age, who had received semi-annual or quarterly fluoride-gel treatments were examined for possible fluoride-induced enamel changes. Further, in order to determine the amount of fluoride retained during the gel treatment, the expectorate was analyzed in 18 younger children presently participating in the prophylaxis program. It was found that the retention of fluoride averaged 7.3 mg per treatment (up to 0.5 mg fluoride per kg body weight). An increased prevalence of dental fluorosis was not observed, even after up to five yearly treatments were given during tooth formation periods. The background prevalence of dental fluorosis in a low-fluoride area in Denmark is described.

Adolescent↗
PubMed1984

Experimental osteo-fluorosis in the domestic pig: a histomorphometric study of vertebral trabecular bone.

The experiment aimed at describing effects of fluoride on structure and remodeling of vertebral trabecular bone in pigs. Eight animals receiving a supplement of 2 mg F-/kg b.w. per day from age eight to 14 mo were compared with eight controls. Plasma fluoride increased from 0.7 +/- 0.1 microM/1 to 12.7 +/- 2.0 microM/1 in pigs receiving fluoride. At slaughter, the concentration of fluoride in dry fat-free bone was 149.3 +/- 10.5 mM/kg for fluorotic animals and 9.5 +/- 0.9 mM/kg for controls. Morphologic changes were assessed in un-decalcified specimens of the fourth lumbar vertebra by quantitative histology using fluorochromes as intra-vital tissue time markers. The volume of trabecular bone tissue (bone + marrow) was unchanged in fluorotic animals, but the volume density of bone was increased by 17%. Surface densities of cancellous bone were almost unchanged, whereas the thickness of trabeculae increased in fluorosis. Fluoride enhanced remodeling of trabecular surfaces: The fraction of surface occupied by resorption lacunae increased 40%, and the formative surface approximately 30%. No changes were demonstrated at surface points undergoing formation: Osteoid thickness, calcification rate, lamellar thickness, and completed wall thickness were normal. It is concluded that the observed findings cannot be explained by fluoride-induced changes in a single cell. Fluoride appears to affect all cells involved in remodeling by direct or indirect mechanisms.

Animals↗
PubMed1982

The relationship between water-borne fluoride, dental fluorosis and skeletal development in 11-15 year old Tanzanian girls.

Dental fluorosis was evaluated by a classification system, previously shown to be sensitive, and skeletal changes evaluated by bone maturity and structure. Dental fluorosis was more severe in posterior than in anterior teeth in both jaws irrespective of fluoride concentration of the drinking water. There appeared to be no dependence between fluoride content of the water and skeletal maturity or structure, but there was a definite relationship between the degree of dental fluorosis and skeletal maturity within the high fluoride area. Fluoride concentrations in the drinking water above 3 parts/10(6) seemed to affect all mineralizing tissues under formation. The unique pattern of enamel formation and mineralization renders it the only hard tissue which permits an early diagnosis of the biological effect of even low fluoride doses on the human body.

Adolescent↗
PubMed1982

Fluoride in mixed human saliva after different topical fluoride treatments and possible relation to caries inhibition.

Fluoride concentrations in mixed saliva were measured at different intervals following topical treatments with various fluoride preparations and procedures such as dentifrice, tablets, mouthrinse and topical solution. The results were related to available caries reduction data from corresponding clinical trials previously published. Salivary fluoride levels varied widely reflecting the different dosages applied, whereas the caries reduction data irrespective of type of treatment appear very similar, with a magnitude of about 30%. When combining salivary fluoride data with recent understanding of enamel-fluoride kinetics it was possible to explain the clinical caries reductions.

Adolescent↗