Archive for the ‘Dental Crowns’ Category

Did my dentist ruin my new onlay?

Saturday, August 28th, 2010

On one of the onlays the dentist recently put in, she filed it so far down (to adjust the bite, she said), that now there’s a sort of crater in the tooth that’s about 3 or 4 mm in diameter, and the color of the tooth there is gray. I think she filed it down way too far. My question is can that onlay be repaired by filling that area the dentist filed too much off of with a composite filling, as if she were filling a cavity? Or is that onlay ruined now? I had told the dentist that tooth was hurting a lot whenever I tried to chew anything, and that I was feeling a really deep-down sensitivity. But she kept telling me the tooth was fine, and she would not acknowledge that she had filed too much off of the onlay. I’m wondering if the onlay is ruined, or if it can be repaired by filling it in with a composite material? I’m hoping that maybe then there will be more of a covering on that part of the tooth, and then the deep sensitivity will stop and also I’ll be able to chew on it without pain. What do you think?
- Monica

Monica,
I’m guessing from what you’re telling me that this is a porcelain onlay that you’re talking about and not a gold onlay, since you mentioned that it now looks gray.

Sometimes, if the tooth wasn’t reduced enough in the preparation appointment and if something wasn’t done right with your bite, or if there’s a problem in seating the restoration accurately, you can end up with a lot of adjustment being required to get the tooth to fit the bite. Usually this won’t affect the integrity of the restoration, but it could. I can’t really tell from what you’ve told me if it has or hasn’t. But repairing it with a composite filling wouldn’t help. If you wear through the onlay later, then a repair could be an option to replacing the onlay. My guess would be that the onlay is fine, but maybe not.

But I’m concerned about the pain you’re feeling when you’re chewing. You’re talking about a deep sensitivity in this tooth. I’m wondering if your tooth is infected.

I’d suggest getting a second opinion. Get a recommendation of a dentist you feel you can trust and ask him or her to x-ray this tooth and examine it to see if it’s okay. That will answer the question about possible infection, and if there is enough onlay left on the tooth to protect the tooth.

Dr. Hall

Problems with your bite can lead to TMJ disorder. Read about Boca Raton TMJ Dentist Dr. Kagan.

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Repairing my gold onlay: amalgam or composite?

Friday, July 9th, 2010

Hello. I have a gold onlay on a molar. I have had it for 28 years and the gold on the top surface of the tooth is worn out. My dentist says he can cut the top off and fill in with amalgam, keeping the gold around the sides of the tooth. I was wondering if composite filling could be used for this to improve the look. I also don’t like amalgam.
Thank you
- Penny from New York

Penny,
Part of your question is simple, and part is a little complicated.

A gold onlay is like a crown that covers the entire tooth, except that it covers just the chewing surface and goes down the sides partway. They can last a long time if they’re done well, and it looks like yours was done well.

Yes, I would much prefer in my own tooth or in a patient’s tooth, to have the hole repaired with white composite rather than amalgam.

Another issue with plugging the hole with amalgam is that you would then have two dissimilar metals in the same tooth. This creates a slight electric current, which would accelerate the corrosion of the amalgam. Plus, a little of the mercury gets absorbed in the surface of the gold.

The complication is that, if your dentist prefers using amalgam here, he is not one I would ask to do the composite repair. Dentists who know how to do the composite repair well almost universally prefer that technique. It is very risky to try to nudge a dentist out of his or her comfort zone. They will not want to reveal their discomfort with a procedure, and it’s a recipe for disaster. These composite fillings are very technique sensitive, and many dentists don’t know how to do them well.

Bottom line – if you want to have your dentist do this, let him do it the way he wants. If you have a problem with that, seek out a dentist who does composites on back teeth routinely. A good way to find such a dentist is to call the office and ask if the dentist does very many silver fillings (as if that is what you wanted). If they tell you the dentist doesn’t do many silver fillings or doesn’t recommend silver fillings, then you can be fairly sure he or she is very comfortable doing composites on back teeth.

Link: See our page explaining that Dr. Kagan is a mercury-free Boca Raton dentist.

Posted in Amalgam vs Composite Fillings, Dental Crowns | Comments Off

My porcelain crown keeps falling out.

Friday, March 12th, 2010

I have porcelain crowns on some of my top teeth. I have had problems with them falling out. This weekend I was eating something and bit down and I didn’t know my tooth fell out – I bit down on it – it shattered and apparently I swallowed most of it. I had it done at my family dentist in 2004 and have been back there several times to have crowns re-cemented in. He usually doesn’t charge me to re-cement but now he wants to charge me $1,100.00 for a new crown. I told him I would pay cost for the crown but that was it, that it should not have fallen out to start with. Is it common to have them fall out as much as mine have? Is this something that I have to pay for?
- Susan from Georgia

Susan,
No, this shouldn’t be expected, that a porcelain crown keeps falling out. If they’re done right they won’t ever fall out. But I can understand why your dentist wants to charge for this, because now he has to make it from scratch, and it’s kind of expensive for him to do this.

What holds crowns in is the near parallelism of the way the tooth is prepared. The more parallel the tooth is prepared, the stronger is the retention. But if the tooth walls are made TOO parallel, there is a risk of what are called undercuts, and the crown won’t fit at all. Different dentists have different levels of comfort with how parallel they will make their preparations. The less parallel they are made, the easier it is to fit the crown.

But then with all-porcelain crowns, they are also bonded to the teeth. And if they are properly bonded, they don’t need a lot of retention in the design.

I’m suspecting that your dentist doesn’t know how to bond porcelain crowns. They’re supposed to be bonded to your tooth, and they get most of their strength from the bonding procedure. It sounds like your dentist has simply cemented it in instead of bonding, as that’s the only reason I could think that an all-porcelain crown would just fall out like that.

Yes, I would say that your dentist should just replace this for no charge. But I don’t believe he’s legally required to do this, and if he has lots of these crowns falling out, I imagine he’s getting tired of doing this for free, and it’s hurting his bottom line.

Posted in Porcelain Crowns | Comments Off

How can you detect decay under a crown?

Saturday, August 15th, 2009

How can decay be detected under crowns - which prevent x-ray viewing?
- Patti from Virginia

Patti,
You’re right that a crown blocks the x-rays. So when you get tooth decay under a crown, sometimes you can’t see it on the x-ray until it gets really large. Fortunately, more often than not the decay is at the margin of the crown, so the dentist can see it below the crown.

The key to preventing recurring decayaround a dental crown is to make the fit so precise that there is no gap or irregularity in the surface where the tooth meets the crown. This is where decay will start—right on that margin. In our office, we provide a lifetime warranty on dental work, because we are so careful with how the crown fits. Getting that perfect fit is the key to a crown that lasts.

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What kind of crown is best?

Tuesday, July 28th, 2009

My back molar on the left bottom side is cracked from a 30-year-old silver filling and the dentist says I need a crown. I am deciding between Cerec, all porcelain, gold, and porcelain fused to gold. I don’t know which one is best for me. I was told Cerec is very hard porcelain and not likely to break. I went to another dentist today who’s a friend of my husband’s and he recommended a gold crown.

My main concerns are the amount of tooth that has to be removed, the effect on the surrounding and opposing teeth, and how soon the crown would need to be replaced. The second dentist said a gold crown would last 20 plus years, a porcelain 10 to 15, if I remember correctly. The Cerec crown appeals to me because I could have it done in one day and wouldn’t need a temporary crown.
- Diane from California

Diane,
If appearance isn’t an issue, then it’s no contest – the gold crown is far superior to any of the other dental crowns. It requires the least tooth reduction, lasts the longest, is the easiest on the opposing teeth, fits the best and is the strongest. It’s only when you get to appearance issues that it makes sense to consider any other type of crown. All porcelain is the least strong but the best looking. Porcelain fused to gold looks pretty nice and is pretty strong, but requires more tooth reduction and because of shrinkage issues with the porcelain doesn’t fit as well as all gold. All crowns that have porcelain in them are abrasive to the opposing teeth and tend to wear down the opposing teeth.

Related links:
You may also want to read about gold fillings.

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Can I get a porcelain veneer over my crown?

Thursday, July 9th, 2009

I have a porcelain crown on my front tooth that I have had since I was 13. It still looks good but has a small crack in it.  Could I have a porcelain veneer put over the top of this instead of getting a new crown made? I just am worried that the crown is going to break. – Georgia from Oregon

Georgia,
Yes, you can get a porcelain veneer put on top of a porcelain crown. But what you really need is a new crown. And there are two excellent reasons.

The first is that if the underlying crown is cracked, then the porcelain veneer that is bonded on top of it will probably crack, too. Porcelain veneers by themselves aren’t very strong – they derive their strength from the underlying tooth and from being bonded to the tooth. Bonded on top of cracked porcelain will make it likely crack.

The second reason is that at most dentists it costs pretty much the same to get a porcelain veneer as it does to get a porcelain crown. It’s about the same amount of work, and the laboratory fee is usually the same. And a new porcelain crown will last much longer than your patched crown. So why patch the crown, pay the full price, and then in two or three years need a new crown anyway? That’s unnecessary expense.

I might add that if the crack in your porcelain crown isn’t noticeable, it could be just a craze line and the crown could last for quite a bit longer. If it’s a crack that goes all the way through, then the crown would probably need to be replaced. But if it’s just a superficial craze line, it may not need to be.

Posted in Dental Crowns, Porcelain Veneers | Comments Off