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Letters: Experiences with amalgam

September 07, 2015 Dr. Stephen Chronister's letter (Letters, July 13 ADA News) seemed to indicate that he thinks amalgam restorations are responsible for tooth fractures, among other things. He indicates the expansion of amalgam when setting is the cause of fractures. His quote, "This is caused by the amalgam," is a very bold statement.

He relates recurrent caries associated with amalgam but he does acknowledge that "any dental restoration" can, and does, have recurrent caries issues. With that I agree.

However, my experience has been a little different from Dr. Chronister's concerning amalgam and composites. Amalgam does expand upon setting but composites shrink upon setting creating "negative" tension versus "positive" tension. This "negative" tension also puts stress on tooth structure and bonding agents and can contribute to open margins.

Recurrent caries seems to me to be very closely related to the patient's quality of oral hygiene; but having said that, it seems to me that recurrent caries issues are more of a problem with composites than amalgams, for whatever reason.

As far as fractures, over the years I have seen fractures in teeth with both amalgams and composites. It seems to me that the extent of the older restoration, the occlusion of the tooth (teeth) involved, paranormal habits (bruxism and clenching) and recurrent caries result in fractures, not an amalgam's expansion upon setting or a composite's shrinkage upon setting.

Many patients of mine have amalgams that are well over 30 years old — some I placed and some placed by other dentists — that are still serving the patients well with no fractures.

I believe we all have our biases that color how we evaluate things, me included. As professionals, we need to be very careful when evaluating situations because that can possibly affect the treatment we render to our patients.

By the way, I do many more composites than amalgams because it looks better and that's what patients want.

Paul L. Powell Jr., D.D.S.
Siler City, North Carolina