Thursday July 2, 2009.

Dear Dr. Mady: You are a special person to help like this. I have a major concern. I am having partial dentures done for the bottom. I always had a plastic partial denture and have had it for thirty years with no shifting of teeth at all. After thirty years of being careful I accidentally threw it in the garbage can so now I am working with a dentist and she said she will make a metal device that connects four missing teeth on one side and three on the other. She said that it would be stronger, but I am concerned about what metals are used and if iron will seep into my system. What metals do they use and are they likely to seep into my blood? Isn't plastic healthier? I have arthritis and also a compromised immune system anyway. I have had a plastic partial for thirty years and have had no problem at all. Kindly help me with my decision if you can. I didn't sleep last night over this. Thank you. Joan in Louisiana

Dear Joan, I am on vacation and checking my e-mail messages but will answer you because it sounds like you need help making a decision and it can’t wait. Evidently your dentist wants to make you a lower cast removable partial denture. I fabricate these very often in my own practice and they are an excellent treatment option for many individuals who do not want to spend the money on dental implants. It would be helpful for you to discuss the exact differences between the acrylic (plastic) and cast metal removable partial dentures. Also inquire with her about other replacement alternatives and the risks and benefits of each.
The cast metal partial denture framework has no iron in it. The partial will still have acrylic or plastic in the areas where you are missing teeth to hold the replacement teeth in place. This type of prosthesis is strong, rigid, has superior strength characteristics and the type we use is made out of non-corrosive ingredients known as chromium-cobalt-molybdenum. The metal involved usually does not have any cytotoxic potential or cause any allergic sensitization. It also polishes very smooth and nicely, limiting plaque adhesion. I have seen an individual that claimed an allergy to this metal, but this was the only one in twenty years and it is very rare. As far as releasing toxins it is usually safe. If you are concerned about an allergy or have had reactions to metals in the past, get tested by an allergist first. This most likely will require a referral from your family physician.
These cast metal partials are usually tooth supported and can be harder on the teeth they hook onto but they are thinner, stronger and last longer than other types. Modifications often have to be made to the natural teeth to help the cast partial adapt better. The acrylic partials like the one you had are usually mostly tissue supported, even though they can have wrought (non-cast) clasps but they are thicker and break easier. In addition to these being easier on the remaining teeth, another tooth can be added to them easily if one is lost and they don’t usually require any natural tooth modifications prior to final impressions. It is more difficult but not impossible to add a tooth to a cast partial and they do seem to last a lot longer.
I hope this helps and believe me your decision is nothing to lose sleep over.
Dr. Mady
            Any questions for Dr. Mady can be e-mailed to and also visit his blog at (dental education network)
This column is reprinted with the permission of the author and The Windsor Star. "Ask the Dentist" is written by Windsor dentist (and ECDS member), Dr. David Mady Jr.. The column appears the first Thursday of each month in the Windsor Star. Readers with questions can write to "Ask The Dentist", c/o The Windsor Star, 167 Ferry St., Windsor Ontario, N9A 4M5


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