An etch resistance phase was found in dental silver amalgam when the amalgam was examined metallographically. This phase was common to the silver alloy ingot as well as to its prepared amalgam. Qualitative electron microprobe technics were used to identify this phase. Quantitative electron microprobe analysis defined it as the R' phase of the copper-tin system or the intermetallic compound Cu6Sn5.

Numerous studies have been done in the past to identify the phases present in dental amalgam. Both metallographic and X-ray diffraction techniques have been used.-' Most researchers now presume that dental amalgam consists mainly of three phases. The original particle is an alloy of Ag, Sn, Cu, and sometimes Zn; the major portion is the compound Ag3Sn, which is often referred to as Py. After am...

Koichi MATSUDA*, Yuji IBARAKI*, Hideyuki SAKAI** and Hirokata SHIMOKOBE** * Department of Operative Dentistry , School of Dentistry, Higashi-Nippon-Gakuen University, Ishikari-Tobetsu, Hokkaido 061-02, Japan. ** Department of Operative Dentistry , School of Dentistry, Hokkaido University, Kita-13, Nishi-7, Kita-Ku, Sapporo, Hokkaido 060, Japan. Received on September 30, 1986 Accepted on Novembe...

Resistance to cefuroxime, penicillin, tetracycline, and mercury is reported for 839 Streptococcus mutans isolates from 209 human study subjects. The MICs of these drugs did not differ for isolates from one dental amalgam group and two nonamalgam subsets: a group with no known exposure to amalgam and a group whose members had their amalgam fillings removed.

Mercury-containing dental amalgam is known to be a source of human exposure to mercury. We have explored the use of electron yield Hg L(III) X-ray absorption spectroscopy to characterize the chemical nature of dental amalgam surfaces. We find that the method is practical and that it shows extensive mercury depletion in the surface of the aged amalgam with significant differences between old and...

The aim of the present study was to compare the reduction of subjective complaints by 3 treatment strategies in 90 "amalgam patients" whose complaints could not be explained by a medical or psychological disorder. The individuals were randomly assigned either to removal of dental amalgam only (removal group), or removal in combination with a "biological detoxification" therapy with high doses o...

OBJECTIVE The attachment behavior of the human periodontal ligament (PDL) fibroblasts to root-end filling materials (amalgam and Super-EBA) was compared in vitro to gutta-percha by means of scanning electron microscope. STUDY DESIGN Amalgam and Super-EBA were placed in a prepared cavity of root slices of freshly extracted human teeth and evaluated freshly prepared. Root slices of teeth with c...

BACKGROUND AND AIM: Surgical endodontics may sometimes fail despite using root-end filling materials (REFMs). In this case report, a symptomatic right maxillary first premolar underwent periradicular surgery (PS) for replacing huge rate of amalgam with mineral trioxide aggregate (MTA).CASE REPORT: A thirty-year-old healthy woman attended with the chief complaint of recurrent swelling and absces...