[Study of biomimetic apatite formation on dentine surface].

The aim of this study was investigation of the opportunity of biomimetic growth of apatite on a dentine surface at various methods of its processing. Artificial blood human plasma--simulated body fluid (SBF)--was used as a source of ions. According to the scanning electronic microscope (SEM) and confocal laser scanning microscope (CLSM) and energy dispersive X-ray analysis (EDX) they have revealed the growth of crystals of calcium--deficient apatite. The structure of the formed apatite layer differed depending on a kind of processing of a dentine surface. After acid etching the globules of the apatite are located chaotically and the part of a dentine surface remains free. The removal of the collagen fibres by NaClO promotes uniform, controllable growth of crystals, forming a monolithic layer. The hypermineralisated areas of a tooth create the best conditions for growth. The transformation hydroxyl apatite in a superficial dentine layer can be caused by increasing of pressure at preparing with diamond bur. The growth of crystals of brushite in the smear layer is possible at a storage in water at 37 degrees capital ES, Cyrillic. The crystals have lamellar form and are well integrated in a dentin surface.

Calcium release and pH-characteristics of calcium hydroxide plus points.

AIM: To evaluate calcium ion release and pH-characteristics of calcium hydroxide plus points (CHPP), conventional calcium hydroxide points (CHP, both Coltène/Whaledent, Langenau, Germany) and aqueous calcium hydroxide suspension (CHS) (Calxyl, OCO, Dirmstein, Germany). METHODOLOGY: Ten CHPP or CHP of size 50 were immersed into 5 mL isotonic sodium chloride solution. Conventional Ca(OH)2-free gutta-percha points served as negative control. Calcium release was measured up to 44 days by means of complexometric titration. Time dependent pH behaviour of all points in comparison with CHS was determined immersing 30 points of size 50 into 2.3 mL 0.9% wt NaCl-solution at time intervals of 0.5-72 h by a microelectrode measuring chain and a pH-meter. The surface morphologies of new and used gutta-percha points were evaluated qualitatively under a scanning electron microscope. Statistical evaluation was carried out using Kolmogorov-Smirnov-tests, Mann-Whitney-tests and multifactorial anova. RESULTS: For CHPP, a threefold greater calcium release was measured compared with CHP. Both types of points as well as CHS showed a maximum pH of approximately 12. Differences between groups were statistically significant for calcium release and pH (multifactorial anova; P < 0.001). Both types of points showed porous surfaces after usage, with a rougher surface for CHPP. CONCLUSIONS: CHPP and CHP increased the pH of isotonic sodium chloride >11 within 3 min. CHPP had a greater release of Ca2+ compared with CHP.

[New direct restorative materials]. / Nieuwe directe restauratiematerialen.

People worldwide have become increasingly aware of the potential adverse effects on the environment, of pollution control and of toxic effects of food, drugs and biomaterials. Amalgam and its potential toxic side effects (still scientifically unproven) continue to be discussed with increasing controversy by the media in some countries. Consequently, new direct restorative materials are now being explored by dentists, materials scientists and patients who are searching for the so-called 'amalgam substitute' or 'amalgam alternative'. From a critical point of view some of the new direct restorative materials are good with respect in aesthetics, but all material characteristics must be considered, such as mechanical properties, biological effects, and longterm clinical behaviour.

New direct restorative materials. FDI Commission Project.

People worldwide have become increasingly aware of the potential adverse effects on the environment, of pollution control and of toxic effects of food, drugs and biomaterials. Amalgam and its potential toxic side effects (still scientifically unproven) continue to be discussed with increasing controversy by the media in some countries. Consequently, new direct restorative materials are now being explored by dentists, materials scientists and patients who are searching for the so-called 'amalgam substitute' or 'amalgam alternative'. From a critical point of view some of the new direct restorative materials are good with respect to aesthetics, but all material characteristics must be considered, such as mechanical properties, biological effects, and longterm clinical behaviour.

CAD/CAM--fillings of the future?

The development of computer aided technology in restorative dentistry has created a range of techniques for the modern dentist. The types of systems now available and the literature published thus far on long term clinical results of restorations created by such techniques are reviewed.

[Transdermal salicylate absorption and behavior of corticosteroid plasma levels during epidermal administration of an antiphlogistic ointment]. / Transdermale Salicylat-Resorption und Verhalten des Corticosteroid-Plasmaspiegels nach epidermaler Applikatiion einer antiphlogistisch wirksamen Salbe.

After repeated epidermal application of an ointment containing salicylic acid, mucopolysaccharidepolysulfate and suprarenal extract (Mobilat) the transdermal absorption of salicylate was determined in seven healthy volunteers by measuring the renal excretion of salicylate as well as the plasma level. The determination of the corticosteroid plasma level was to elucidate a possible effect caused by the suprarenal extract contained in Mobilat ointment. By means of high pressure liquid chromatography the concentrations of salicylic acid and salicyluric acid in the collected urine and in the plasma were established. The quantitative determination of hydrocortisone, 11-desoxycortisol and 17 alpha-hydroxyprogesterone, selected as indicator steroids, was performed by radioimmuno assay. After repeated application of Mobilat ointment a constant level of salicylic acid in plasma of approximately 0.2 microgram/ml was observed. The total excretion of salicylate reaches a constant level of approximately 12 mg/day. About 6.9% of the amount of salicylate was renally excreted after 7 days. The corticosteroid plasma level showed no significant change.