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Biomedical subjects

G Daculsi

Publications and source records attributed to G Daculsi.

At least 145 records · Page 8Linked to original sources
PubMed1983

In vitro caries-like lesion formation in F-containing tooth enamel.

In vitro caries-like lesion formation in F-containing tooth enamel (shark) showed a lower depth of penetration compared to that in human enamel (42 vs. 100%). After longer periods of exposure, the depth of penetration in shark enamel is only 33% relative to that in human enamel. The extent of dissolution in acetate buffer for powdered human enamel and for synthetic F-free calcium-carbonated-apatites was greater than for powdered shark enamel and for synthetic F-containing apatites. These results suggest that the cariostatic action of fluoride may be explained in terms of a combination of two effects: (a) the stabilizing effect against acid dissolution (caries) when fluoride is incorporated in the tooth mineral (apatite), and (b) a greater degree of remineralization (repair) in the presence of F solution.

Animals↗
PubMed1982

[The posterior manubrial ligament].

The posterior manubrial ligament is part of the suspensory ligamentous system of the ossicles, and extends backwards from the posterosuperior spine of the tympanic notch to the postero-internal portion of the manubrium just below the neck of the malleus. It lies in relation to structures in the posterosuperior region of the tympanic barrier to downwards extension of epitympanic recess lesions during chronic otitis.

Ear, Middle↗
PubMed1982

Apatites in heterotopic calcifications.

Calcified material obtained from three patients suffering from calcifications of the shoulder tendon sheath and from a subcutaneous with calcinosis was studied. A panel of different techniques was applied to this study: scanning electron microscopy, X-ray diffraction, infrared spectrometry, scanning and transmission wavelength dispersive X-ray spectrometry, high resolution transmission electron microscopy and electron microdiffraction. These calcifications, made of carbonate containing apatite, are heterogeneous and composed of at least two separate phases the crystallinity of which appear different.

Apatites↗
PubMed1981

Effects of fluoride on human enamel and selachian enameloid in vitro: a high-resolution TEM and electron diffraction study.

The effects of fluoride on human enamel and selachian enameloid in vitro were visualized in TEM and analyzed with electron diffraction. It is demonstrated that under precise pH conditions, inducing concentration balance between F-ions and apatite, calcium fluoride is no longer formed, and crystalline changes occur instead. A secondary growing process, inducing a twofold increase in crystal size, involves all crystal faces, altering the hexagonal symmetry. It is suggested that the mechanism involved is not a dissolution/precipitation process but rather a secondary growth of residual crystallites induced by apatite dissolution.

Animals↗
PubMed1981

The inorganic phase in dentinogenesis imperfecta.

The inorganic phase in dentin with dentinogenesis imperfecta was investigated, using the correlated techniques of high resolution TEM, X-ray diffraction analyses, infrared absorption spectroscopy, thermogravimetry, and chemical and electron microprobe analyses. It was shown that crystallites in dentin with dentinogenesis imperfecta are of normal size (from 3 to 6 lattice planes thick), but less numerous than in normal dentin. Electron microprobe analyses indicated significant differences in the mineral content of dentin with dentinogenesis imperfecta compared to normal dentin. A higher Ca/P ratio, a loss in Ca and P, and a severe significant loss in Mg, corroborated by chemical analyses, were recorded. The main component of the inorganic phase in dentin with dentinogenesis imperfecta was found to be poorly crystallized carbonated apatite. It is suggested that the water content, greatly increased in dentin with dentinogenesis imperfecta, is at least partly related to lattice water tightly bound to the inorganic phase.

Adolescent↗
PubMed1981

[Effect of vitamin D3 and vitamin D3 sulfate on dental and bone tissues in the pig].

The repairing effects of vit. D3 and vit. D3 sulfate upon the hard tissues of vit. D3 deficient pigs have been studied using SEM and electron microprobe analyses. It was demonstrated that a vit. D3 therapy could balance lesions induced by vit. D3 deficiency. The effects of vit. D3 sulfate were not so clear. Results obtained were varying, sometimes similar to those obtained with vit. D3 but not always statistically significant. The rate of mineralization of dentine and bone was higher in animals having received vit. D3 and vit. D3 sulfate compared to the deficient group. In dentine and bone, the Ca/P ratio, thus the crystalline phases, wee modified, which was not the case for enamel and acellular cementum. It was shown that dentine and bone, which both include cells and cell processes in the calcified matrix, undergo similar modifications in the course of vit. D3 deficiencies and their therapy. On the contrary, enamel and acellular cementum in vit. D3 deficiency presented a lower rate of mineralization without any structural defects or modifications in Ca, P, Mg and F- ratios. Repair of lesions due to vit. D3 deficiencies by vit. D3 and, to a lower degree, by vit. D3 sulfate, concern, in order, bone, dentine, cementum and very little enamel.

Animals↗
PubMed1979

Ultrastructural studies of enamel crystallites.

High resolution electron microscopy has provided precise measurements of human enamel crystallites from the first stages of enamel development to the last stage of maturation, through counting of lattice planes and statistical analysis. Thickness and width measurements of human enamel crystallities in their mature stage are 263 A (21.9 standard error) and 683 A (134 standard error), respectively. The growth curve of enamel crystallites was drawn, the increase in the number of lattice planes in the course of enamel development was demonstrated. Fusions and dislocations related to the maturation process were visualized and discussed. Difficulties linked to the use of ultrastructural techniques were mentioned. The question of the organic stroma of the crystals remained unsettled.

Ameloblasts↗