True about delayed expansion:
Correct Answer: All of the above
Description: Another important additive to amalgam alloy is zinc. Originally, zinc was added to conventional amalgam as a processing aid to suppress oxidation of the key elements in the alloy.
Zinc tends to oxidize preferentially forming a zinc oxide film that covers the surface of liquid alloy during manufacture and suppresses oxidation of other elements.
Generally, 1% or more is added to accomplish this end. However, some (0.2% to 1%) is left in the amalgam alloy at the end.
A detrimental side effect of this residual zinc was that moisture contamination before setting converted the zinc to zinc oxide and produced hydrogen gas that could expand the amalgam excessively, resulting in patient pain, a phenomenon called as delayed expansion.
Category:
Dental
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now