Expert: Mark Bornfeld DDS - 10/24/2007

Question
QUESTION: I went to a dentist for a cleaning and he told me he wanted to take out my silver filling and put in a better filling because silver is not used anymore.  Before the procedure I had no pain and after the procedure everytime I bite on this tooth I get a sharp pain.  The dentist had me come back in the next day because he thought the filling might be too high.  The sharp pain did go away, but now I have a constant pain around that tooth.  My dentist now tells me I need a root canal.  What should I do at this point?  Get the root canal (cost $850), see another dentist, or is this normally what happens when you take out silver and put in a new filling.

Thanks

Kevin Markgraf


ANSWER: Dear Mr. Markgraf,

I'm not sure I fully understand your dentist's rationale for replacing the previous filling. If the silver filling was otherwise providing good service, there was no tooth decay around the filling, and it was bearing up structurally against the rigors of chewing, then replacement of the filling was not justified-- unless you yourself made a specific request that you wanted the improved appearance of a composite resin filling.

Composite resin is in several ways an inferior filling material when compared to the more conventional silver amalgam, at least in terms of their respective physical properties (by the way, silver is still extensively used by the dental profession, although your dentist may have decided for his own reasons to discontinue HIS use of the material). One of the unfortunate qualities of composite resin is its pronounced tendency to irritate the pulp (nerve) of the tooth. In fact, postoperative sensitivity, pain, and pulpal infection are more common following the placement of a resin filling than following the placement of comparable amalgam fillings.

It is possible that root canal therapy may be your only recourse if this tooth is to be salvaged. However, you may wish to explore whether the original filling merited replacement, and a second opinion may be helpful in making this determination. Be sure to obtain x-rays of the tooth that were taken PRIOR to the placement of the new filling if you wish to explore this option.

Hope this helps...

Mark Bornfeld DDS
www.dentaltwins.com
Brooklyn, NY

---------- FOLLOW-UP ----------

QUESTION: My dentist before removing the silver filling used a DIAGNOdent to detect the decay.  The reading was 45 he also filled to other teeth that had a reading of 15 for both.  This is what I found on the DIAGNOdent on the Internet.

Can DIAGNOdent read caries under an existing amalgam?
A: If there is caries at the margin, it will give an accurate reading; however if the caries is under the floor of the amalgam the reading will not be accurate.

Can you please explain to me what caries at the margin are and what caries under the floor of the amalgam are?

Thanks

Kevin Markgraf


Answer
Dear Mr. Markgraf,

The margin of a filling is the line of demarcation at which the filling material meets the tooth enamel AT THE SURFACE of the tooth, as opposed to where the filling meets the tooth inside the cavity. The margin, because it is at the surface and not covered by the filling, is directly accessible to sight and to touch, so tooth decay at the margin is quite conspicuous, whereas tooth decay inside the cavity or under a filling can usually be detected only by x-ray, or as an incidental finding if the filling is removed for some other reason.

I should say that I can't resist a jab at DIAGNOdent. It is certainly an interesting bit of technology, and is fascinating, if only from the theoretical standpoint. But as a clinical tool, it is the proverbial "cure for which there is no disease." The rationale usually provided for justifying its use is that it can detect tooth decay before it could otherwise be detected by more conventional means. That may indeed be true, and the early detection of tooth decay is a worthy goal, at least in the abstract. However, far and away the most common reason for late decay intervention is not due to any shortcomings in the conventional diagnostic protocol, but rather because patients sometimes don't present themselves at their dentists' offices frequently enough. DIAGNOdent is no better than the traditional means of decay diagnosis in tackling this problem. In fact, DIAGNOdent has a particularly egregious shortcoming, in that although it is indeed quite sensitive, it is not particularly selective. What this can lead to is a high number of false positive readings, especially if the instrument is not regularly and skillfully calibrated. Unfortunately, this fault is too easily exploited by unscrupulous dentists to justify treatment that is not supported by more reliable diagnostic data.

Mark Bornfeld DDS