Wednesday, May 9, 2012


Many of our patients come to us asking for the facts about silver fillings.  Do they need to have them replaced?  Are they a health risk or just unsightly?

What is a silver filling?

Silver fillings, also called, mercury or amalgam fillings, have been used in dentistry for more than 150 years.  They are made up of 50 percent mercury mixed with silver, copper, tin and other metals.  Mercury fillings were created as a less expensive alternative to gold over 100 years ago.  The use of mercury, one of the most toxic substances on earth, has prompted some of our patients to question the safety of these fillings. 

Should I be concerned about having this material in my mouth?

According the the American Dental Association, as long as the amalgam is intact, the risk of mercury contamination is low.  The risk comes when the silver fillings start to break down as they age.  The FDA has concluded the levels of mercury in dental amalgam are not high enough to harm patients.  However, they classified it as a class 2 device, meaning it has moderate risk and the FDA has left the issue open for further discussion.

As continued research is done on using mercury for fillings, we focus our concerns on the potential dental problems silver fillings can cause, most commonly tooth fractures and recurrent decay.  Dr. Zollinger decided nearly 30 years ago not to use silver fillings both for it’s potential toxic effects but also because its use required a lot of good tooth to be destroyed in the process. 

What is the problem with silver fillings?

Amalgam does not bond to the tooth.  This requires the dentist to wedge the filling into the tooth to keep it from falling out.  It also allows decay to get under the filling material over time where it can grow, sight unseen for a long time before causing any pain.  Dental xrays cannot see through the mercury filling so these areas of decay are nearly impossible to see.

As mentioned before, the placement of silver fillings require the removal of a lot more healthy tooth structure than other materials such as composite.  This can weaken the tooth structure making cracks and fractures more likely in the future. 

The material also expands and contracts.  These expansions and contractions can cause the tooth to crack and split over time. 

What does this mean to me?

The two very common problems we see when replacing old amalgam fillings is fracturing and decay of the tooth surrounding the silver filling, resulting in the need for a root canal treatment or a crown and sometimes both. 

The lack of a bond between the amalgam and tooth may permit bacteria to find its way underneath the filling.  This can cause decay that is frequently not detected until the tooth has suffered more damage.  We see decay under silver fillings in about 80% of silver fillings that we replace.  A lot of times, by the time we see the patient this decay has already made its way into the nerve and root canal treatment will be necessary. 

The other problem is that due to the compromised tooth structure, a lot of times teeth with silver fillings ultimately become cracked or fractured and need to be replaced with a crown.  Dr. Zollinger watches for any cracks or fractures surrounding silver fillings during your preventative visits.  If he sees these, he will suggest that you look at replacing that filling before any more damage occurs.

How are the fillings that you do different?

In comparison, in our office we only use the newer tooth-colored composite resin which is adhesive, highly cosmetic and mercury-free.  It has a lot of great benefits:

·         The color can be closely matched to the patient's natural teeth.
·         The filling material is strongly bonded to the tooth using a state-of -the art technique that intimately binds the material to the surrounding tooth structure.  This means there is very little chance that bacteria will get between the filling and the tooth causing further decay.
·         Less tooth is lost because composite resin fillings can be made much smaller than an amalgam, so less natural tooth structure is lost, reducing the risk of future fracturing.

What do I do if I have concerns about my silver fillings?

If you have concerns about your silver fillings, feel free to set up an appointment for a free consultation.  We’ll be happy to take a look at your options with you.


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