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Corrosion of five different dental amalgams
W J van der Merwe1, F A de Wet, R I Mc Crindle
1Faculty of Dentistry, Medical University of South Africa.
The Journal of the Dental Association of South Africa = Die Tydskrif Van Die Tandheelkundige Vereniging Van Suid-Afrika
|November 1, 1991
Summary
The gamma-2 phase, a key factor in dental amalgam corrosion, was detected in South African amalgams. Only Dispersalloy showed no gamma-2 presence initially, while others exhibited electrochemical activity.
Area of Science:
- Materials Science
- Electrochemistry
- Biomaterials
Background:
- The gamma-2 phase (Ag2Hg3) in dental amalgam is known to be susceptible to corrosion.
- Understanding gamma-2 presence is crucial for assessing amalgam durability and biocompatibility.
Purpose of the Study:
- To determine the presence and electrochemical activity of the gamma-2 phase in two South African dental amalgams.
- To compare these findings with amalgams known to contain or lack the gamma-2 phase.
Main Methods:
- Samples of Amalgaphase, Silvalloy, Amalcap, Dispersalloy, and Permite-C were prepared following ISO standards.
- The rotating disc electrode technique was employed to assess electrochemical activity indicative of gamma-2 presence.
- Electrochemical evaluations were conducted at 24 hours and nine days post-preparation.
Main Results:
- Dispersalloy showed no detectable gamma-2 at 24 hours.
- Amalgaphase, Silvalloy, and Permite-C exhibited electrochemical activity between -200 and -250 mV at 24 hours, indicating gamma-2 presence.
- After nine days, only Amalcap, a known gamma-2 containing amalgam, retained a detectable reaction peak.
Conclusions:
- The South African amalgams Amalgaphase and Silvalloy contain the gamma-2 phase, exhibiting electrochemical activity.
- Further clinical studies are necessary to ascertain the long-term clinical performance and durability of these South African dental materials.