No abstract

Modern dental alloys have been used for 50 years to produce prosthetic dental restorations. Generally, the crowns and frames of a prosthesis are prepared in dental alloys, and then veneered by feldspar ceramics or composites. In use, the alloys are exposed to the corrosive influence of saliva and bacteria. Metallic dental materials can be classified as precious and non‐precious alloys. Precious alloys consist of gold, platinum, and small amounts of non‐precious components such as copper, tin, or zinc. The non‐precious alloys are based on either nickel or cobalt, alloyed with chrome, molybdenum, manganese, etc. Titanium is used as Grade 2 quality for dental purposes. As well as the dental casting alloys, high purity electroplated gold (99.8 wt.‐%) is used in dental technology. This review discusses the corrosion behavior of metallic dental materials with saliva in “in vitro” tests and the influence of alloy components on bacteria (Lactobacillus casei and Streptococcus mutans). The test results show that alloys with high gold content, cobalt‐based alloys, titanium, and electroplated gold are suitable for use as dental materials.

Die bislang nicht bekannten, unterhalb etwa ‐90°C existierenden Verbindungen K2Cs und K7Cs6 werden beschrieben.

Die Verbindung (I) wird als erster Vertreter einer Reihe von gemischten Rb‐Cs‐Suboxiden durch Umsetzung stöchiometrischer Anteile der Elemente dargestellt, wobei der Sauerstoff durch thermische Zersetzung von HgO erzeugt wird.