Biomedical subjects

P Hørsted-Bindslev

Publications and source records attributed to P Hørsted-Bindslev.

3 recordsLinked to original sources

PubMed1998

Discrimination between restorative dental materials by their radiopacity measured in film radiographs and digital images.

The aim of this study was to investigate the possibility of differentiating between various dental restorative materials by means of their radiopacity. Ten extracted molars and ten canines/anterior teeth were selected for the study. In the molar group a class II cavity and in the canines/anterior teeth group a class III cavity were cut by airrotor. The cavities were coated with vaseline before filling with five molar- and three anterior tooth restorative materials in the following sequence: for molars: amalgam, light-cured composite, glass ionomer cement, reinforced glass ionomer cement and light-cured composite. After each filling sequence radiographs were taken of the teeth on conventional film (Ektaspeed Plus) and by two digital systems: a storage phosphor plate (Digora) and a ccd-based sensor (Sidexis). Density was measured in the films with a densitometer in three areas of "air", in three areas of the class II fillings and one area of the class III fillings. The same areas were measured in the digital images where the program calculated automatically the mean grey shade values. The density values obtained from the filling areas were taken as a proportion of the values obtained from the areas of "air". Statistically significant differences in material density when related to "air" density (Wilcoxon's test) were observed between all materials in film (p < 0.01 for molars and p < 0.02 for canines/anterior teeth). For Digora only half of the materials differed significantly which was also the case for the Sidexis system (none of the CF materials were significantly different). In conclusion, the molar filling materials could be distinguished with a high probability in film while the two digital systems were less reliable. The results may be useful in forensic dentistry.

Absorptiometry, Photon↗

PubMed1993

[Dental amalgam: a toxicological evaluation].

During the latest decades the use of dental amalgam has been discussed with respect to potential toxic effects of the mercury component. In order to evaluate potential risks from this practice the recent literature is reviewed. Corrosion of fillings results in liberation of mercury. The absorption from this source in the Danish population can be estimated to be one to five micrograms/24 hrs. This exposure level is far below that accepted in occupational exposure and far below the minimum toxic level. Investigation of placental transfer of mercury has not provided any reason to avoid using amalgam during pregnancy. Micromercurialism or metal syndrome is claimed to be related to amalgam fillings. This syndrome consists mainly of complaints from the central nervous system, but also from muscles, joints and the gastrointestinal tract. The symptoms are non-specific and the documentation of the existence of such a syndrome related to mercury exposure is weak. The symptoms reported can be due to other chemical exposures, but psycho-social conditions may also play an important role. Information on disappearance of symptoms after removal of fillings may be a result of a placebo effect, which may be suggested until controlled experiments are performed. For this reason the use of chelating therapy is not indicated. Allergic contact eczema observed in few individuals is the only problem documented in connection with the use of amalgam fillings.

Brain↗

PubMed1990

Traces of mercury in organs from primates with amalgam fillings.

In order to trace possible accumulations of mercury, three vervet monkeys received occlusal amalgam fillings, three others maxillary bone implants of amalgam, and three untreated monkeys served as controls. One year later all animals were sacrificed by transcardial perfusion with glutaraldehyde. Tissue sections from different organs were subjected to silver amplification by autometallography and analyzed at light and electron microscopical levels. It was found that amalgam fillings (total, 0.7-1.2 g) caused deposition of mercury in the following tissues: spinal ganglia, anterior pituitary, adrenal, medulla, liver, kidneys, lungs, and intestinal lymph glands. In monkeys with maxillary silver amalgam implants (total, 0.1-0.3 g), mercury was found in the same organs except for liver, lungs, and intestinal lymph glands. Organs from the three control animals were devoid of precipitate. To evaluate whether silver released from the corroding amalgam fillings added to the staining pattern, tissue sections were exposed to potassium cyanide prior to being autometallographically developed. This treatment removes all traces of silver, leaving mercury sulfide accumulation untouched. By comparing sections that had been exposed to cyanide with untreated parallels no difference was seen in the pattern confirming that mercury was the only catalyst present in the tissue. These results strongly support what has been suggested previously that dental fillings in primates cause absorption of mercury released from amalgam fillings through lungs and intestinal tract, and that depending on exposure mercury is distributed to most organs and will eventually be found in the central nervous system. The present data also show that silver released from the corroding filling is not absorbed.

Animals↗