A lot of plaque buildup on my new crown. Why?

Three weeks ago a permanent crown was cemented onto my lower back tooth. It apparently isn’t the same shape my natural tooth was. Floss gets caught; it doesn’t move smoothly back up the tooth. I can also feel what seems to be a gap in the back; it’s tender between the crown and my gum. I went to my dentist for a follow up yesterdaty. He said the crown is cemented in perfectly and what I feel is plaque build up. He gave me a rubber tipped instrument and a tiny brush to help me remove the plaque. I was in a rush and had to leave his office, so I neglected to question him. Before I contact him again I’d like to know how plaque can build up to such a great extent in a 3 week timeframe. Shouldn’t the tooth have been thoroughly cleaned before the final cementing? I paid $1000+ out of pocket and feel the additional maintenance I will now have to perform nightly. Is it unreasonable to ask to have the crown redone? Thank you,
– Alice from Wisconsin

Alice,
I’m not sure that I’m understanding what is happening with this crown. Does the floss actually get caught? Or is it just not smooth? And if it’s tender between the gum and the crown, I’m not sure where you mean. Or is it the gum that is tender?

The fit and function of crown or bridge work is a point of differentiation in the skill of dentists. With a well-done crown, you won’t even know that it is there. There are a number of little things that can go wrong with a mediocre crown. It seems that you are having some of these things.

If the shape of the crown where it touches the tooth adjacent to it isn’t right, or if there is a little gap between the crown and the adjacent tooth, it can catch food or be a plaque trap. Not only is this annoying, it can be irritating to the gums, making the gum sore, and it can promote tooth decay either on that adjacent tooth, or on the tooth with the crown – the decay will start on the root of the tooth below the part that the crown covers. In three weeks, you could easily accumulate a large amount of plaque there.

And if the margin of the crown (the place where the crown meets your tooth) doesn’t fit just right, you can have a rough edge there. An overhang is a situation where there is a ledge at this margin. This ledge will catch floss and can also catch food and accumulate plaque. And it will also be irritating to the gums and can contribute to gum disease.

And with each of these problems, there are degrees. A slight overhang, or ledge, is only a slight problem, and you may be able to compensate for that with more careful flossing. And there are some clinical situations, such as decay that goes way down the root of the tooth, where it can be very difficult for even a skilled dentist to get an ideal margin. But I would suggest asking your dentist about these problems. I would suggest telling your dentist that you found, through research on the Internet, that you could be having one or more of these problems with your crown, and that you would like this fixed or at least explained a little more satisfactorily. If you don’t get a satisfactory resolution, then I would get a second opinion. A simple rough edge may able to be smoothed, and that would take care of the problem. If the problems are significant enough, re-doing the crown would be justified.

Links: Read about Naperville dentist Dr. Newkirk’s porcelain veneers, and see porcelain veneers pictures.