In vivo remineralization of human enamel and dental calculus formation.

The aim of this investigation was to determine the inorganic composition and the surface morphology of remineralized enamel areas and of dental calculus in heavy-calculus-formers (five subjects) and to compare these results with those of non-calculus-formers (two subjects). Electron probe micro-analysis (EPMA) was carried out on sound, acid-etched, and in vivo remineralized enamel samples from heavy- and non-calculus-formers. The mean values of Ca, P, Na, Mg, Al, Si, S, Cl, and K were compared with the SEM morphology. EPMA measurements showed no significant differences in the Ca/P ratio of the surface layers of prism-oriented and/or homogeneous enamel remineralization. The variations of remineralization pattern after acid-etching are similar in teeth from heavy dental-calculus-forming patients and in teeth from non-calculus-formers. The SEM appearances of remineralized areas and of the inner surface of mature dental calculus must be considered to be totally different. The experiments carried out suggest that the remineralization of enamel is not related to the formation of calculus.

[Superficial and marginal behavior of composite filling materials in class III and II cavities as compared with conventional filling materials (author's transl)]. / Oberflächen- und Randverhalten von Kompositionsfüllungsmaterialien bei Klasse-III- und II-Kavitäten im Vergleich zu konventionellen Füllungsmaterialien.

The superficial and marginal behavior of composite filling materials is better than that of conventional types of front tooth filling cements as regards plaque retention, danger of marginal caries, and microleakage with potential damage to the pulp caused by bacterial toxins.--According to the results obtained in vitro, Evicrol is a positive alternative to Frontasil and Achatit-biochromatic. Plastic foils are not suitable as matrices, whereas aluminum matrices have been found to meet the requirements of surface smoothness and anatomical adaptability in cavity classes III, IV, and V. Celluloid matrices show inadequate adaptational properties, although they offer smoothest surfaces. The marginal behavior of Evicrol in class II cavities in molars is virtually the same in the case of both conventional retentive preparation and modified preparation of initial occlusal-approximal defects by the enamel etching technique. Discontinuous microretentive securing of matrix tags in the enamel etch pattern corresponds neither occlusally nor approximally to the physical definition of adhesion in different areas of the enamel. Clinical comparison in a 12-month study with the results obtained in vitro restricts safe indication to classes III and V, it being necessary to give careful consideration to the directions for use.--Long-term clinical longitudinal studies are required to determine permanent successes of treatment and possible extensions of the range of indications.

Modification of the surface structure of murine peritoneal macrophages following chemotherapy. A scanning electron microscopic study.

The effects on peritoneal macrophages of some chemotherapeutic agents administered subcutaneously to conventional male AB/Jena mice were studied. beta-[1-ethyl-(5-bis-(beta-chloroethyl)-aminobenzimidazolyl-(2)]-DL-alanine (IMET 2925), beta-[1-phenyl-5-bis-(beta-chloroethyl)-amino-benzimidazolyl-(2)]-DL-alanine (IMET 3164), and gamma-[1-phenyl-5-bis-(beta-chloroethyl)-amino-benzimidazolyl-(2)]-butyric acid (IMET 37/70) evoked a pronounced variation of the cell surface consisting in a shortening, coarsening and reduction in number of the microvili and other projections. Likewise, 1.3-bis(piperidinomethyl)-5-ethyl-5-phenyl-barbituric acid induced a flattening of the surface, but the structures appeared to be increased in number per area. Chlorambucil, 6-mercaptopurine, and 5-fluoro-uracil failed to provoke any obvious change in the threedimensional cell surface structure. These morphological findings are consistent with functional results reported previously.