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Biomedical subjects

U Belser

Publications and source records attributed to U Belser.

25 records · Page 2Linked to original sources
PubMed1975

The precision of three enamel biopsy methods for fluoride determination.

3 different enamel biopsy methods were tested on 2 maxillary permanent incisors on each of 90 schoolchildren. In methods A and B the round biopsy field was bordered by copalite varnish, while method C utilized a scotch tape border. The biopsy itself resulted from etching the enamel surface with 2N perchloric acid for 7 sec for method A, and 14 sec for methods B and C. Flouride was measured with the fluoride activity electrode. The doubled etching time caused only a 30 to 40% increase of enamel removal. Method C showed the best reproducibility.

Adolescent↗
PubMed1975

Uptake and retention of fluoride by intact and etched enamel.

180 fluoride biopsies were taken in 30 children from the labial surfaces of the 6 maxillary anterior teeth. The average thickness of the biopsied surface enamel was 8.35+/-0.75 mjm. Intact, not treated enamel had an average F-content of the integral of 550 ppm. 7 days after one 3-min topical application of amine fluoride on intact enamel the average F-concentration was the integral of 1150 ppm. 7 days after one amine fluoride application on enamel previously etched with pyruvic or orthophosphoric acid, the average F-content was the integral of 3400 ppm and the integral of 2800 ppm respectively.

Adolescent↗
PubMedDate not supplied

Esthetic improvements and in vitro testing of In-Ceram Alumina and Spinell ceramic.

The original In-Ceram material (In-Ceram Alumina), composed of sintered aluminum oxide subsequently infused with a glass, features interesting mechanical properties. In-Ceram Spinell was marketed more recently to improve the esthetic potential. This study compared the flexural strength of various combinations of sintered alumina and spinel infiltrated with the associated glasses. In addition, the influence of vacuum during the infusion process was investigated using density measurements. The characteristic strength (load at which 63% of the specimens had failed) was 530 MPa for the original material, 523.7 MPa when the same material was infiltrated under vacuum, 481.4 MPa when sintered alumina was infused under vacuum with the glass originally marketed for the spinel, and 283.1 MPa for the sintered spinel infiltrated under vacuum with the associated glass. A significant increase in density was observed when the infiltration firing of sintered alumina was performed under vacuum. Furthermore, the in vivo evaluation of specific esthetic parameters inherent to different types of cores was made and revealed the relative opacity of alumina; spinel was found to have the ability to blend in with the underlying substrate. Both materials demonstrated a general lack of fluorescence.

Aluminum Oxide↗