Is a leaky filling an urgent matter?

Hi Dr. Hall,

I tried out a new dentist this morning and have a question about his recommendation.

I have two composite fillings on two different back molars and he told me that they are leaky and have potential for failing. He recommended that I have them removed and replaced with newer, better materials. Is this an urgent situation? He said he may only have to remove part of one of them but it would probably be best to have them both redone to fix the seals.

– Jamie from Colorado

Jamie,
A leaky filling is a legitimate situation that needs treatment. A gap can form between the tooth and the filling and bacteria can get in there and decay can start then under the filling. That’s called recurrent decay, and the technical term for the process is microleakage.

A nice thing about composites is that it is easier to tell when decay starts to get around them. With amalgam, often the decay is hidden until it actually gets under the filling and has grown to some size, at which point it is fairly advanced. I can’t tell you how many amalgam fillings I removed that I thought were sound but the patients just wanted them out because they didn’t like them, and I was surprised to find decay under them. But these surprises don’t usually happen with composites.

Is it urgent to replace a leaky filling? That depends. With an amalgam, you often don’t know if there is decay under it or how much decay. Decay under a filling starts pretty deep into the tooth, so your tooth could be close to becoming infected. In that case, yes, it is possibly urgent. But with composite, which is what you have, it is easier to tell if there is decay. And, from the way you are phrasing what your dentist is saying, there isn’t decay yet, just the risk of decay.

And yes, if they are leaky, it would be best to replace the entire filling and get a better seal. If the old filling is leaking in one place, it may start leaking in another.
– Dr. Hall