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.

The aim of this study was to investigate if a videotaped feedback method enhanced teaching and learning outcomes in a preclinical operative laboratory setting for novice learners. In 2013, 60 dental students at a dental school in India were randomly assigned to two groups: control (n=30) and experimental (n=30). The control group prepared a Class II tooth preparation for amalgam after receiving...

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 objective of this study is to share cost analysis methodology and to obtain cost estimates for posterior restorations in public sector dental clinics. Two urban and 2 rural dental clinics in Selangor state were selected. Only cases of 1 posterior restoration per visit by dental officers were included over 6 months. One capsulated amalgam type, 1 capsulated tooth-colored, and 1 non-capsulate...

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...