Why does my crown keep falling off?


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Dr. Hall,
I have had a crown put on by a dentist and it was done same day. No temporary. Not sure what type of material he used for the crown. It fell out three times in less than a year. I went to a different dentist on the fourth time it fell out and he replaced the setting with a new one stating the other dentist didn’t create a good setting. This new crown is Zirconia Porcelain and it has fallen out twice in a month. He is suggesting a full porcelain crown on the same setting as he states the cement is adhering to my tooth but not the crown. He says the all porcelain has a more rough underside to adhere to the cement better. Any suggestions on what my next move should be?
– Stephanie from North Carolina

Stephanie,
Your same-day crown was a CEREC crown or a similar type that is milled by a computer in the dental office while you wait. But when properly prepared and bonded on, it will stay on permanently. It’s not the material your crown is made of. Gold crowns, porcelain crowns, CEREC crowns, zirconia crowns–all of them can be made to stay on solidly, permanently. I have most of those types of crowns in my own mouth and they stay on just fine.

There are two main factors for retention of a dental crown–the bonding strength of the cement, and the shape of the tooth preparation. Of those two, the shape of the tooth preparation is far more important. If the tooth is prepared with only a slight taper, a crown can be cemented with a very weak cement and it will still stay on. If it is prepared with a lot of taper, some of the strongest cements will not hold it on.

I’m not saying that getting a good bond between the crown and your tooth wouldn’t solve your problem. The strength of the cement is a factor. And I know very little about your tooth and the techniques these dentists used. But I do know that a tooth prepared with good retention form will not have a crown falling off three times in less than a year, regardless of the cement used. So even though I know very little about your tooth, I’m pretty confident that it was prepared with inadequate retention form.

So what should your next move be? I would find a dentist who knows how to do crowns that stay on. In 23 years of dental practice, I never had a crown fall off of any that I did for my patients, so I know it can be done.

For further understanding of this principle, of creating a crown that stays on, see my blog post from about nine months ago, “The main reason your crown probably fell off.”

I hope this is helpful.
Dr. Hall

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About David A. Hall

Dr. David Hall was one of the first 40 accredited cosmetic dentists in the world. He practiced cosmetic dentistry in Iowa, and in 1990 earned his accreditation with the American Academy of Cosmetic Dentistry. He is now president of Infinity Dental Web, a company in Mesa, Arizona that does complete Internet marketing for dentists.

I want CEREC crowns on my two front teeth

Dr. Hall,
I broke my two front teeth in an accident, and they both need crowns. I really want the same day crowns, and my dentist doesn’t do them. Should I ask him for a referral?
– Nolan from Florida

Nolan,
You THINK you want same day crowns, but I’m not sure you really do.
Your answer to this question will tell me whether or not you want CEREC (same day) crowns for these two teeth. Which is more important to you–that they look natural, or that you take care of this in one appointment without having to wear temporary crowns?
Your front two teeth are the most important teeth in your smile, and most people would be willing spend a little more or go through a little more inconvenience to get them looking just right. CEREC crowns simply aren’t that esthetic.

Let me illustrateshould you do a CEREC crown on a front tooth? with a close-up photo of a front tooth.

Look closely at the coloration in this tooth. Notice that there is a tannish color present at the base of the tooth that fades out as you get to the halfway point. Notice also some subtle white splotches in various places. There are a couple near the base of the tooth and some more subtle ones near the center. There is also some gray that you see near the biting edge and wrapping around the sides of the tooth a little. And the very biting edge has a whiteish halo.

A porcelain crown for a front tooth is stacked in layers, and a good ceramist operating from good instructions from a skilled cosmetic dentist and maybe from a photograph will build all of these different colors into your crown, so that it looks lifelike. A CEREC crown, on the other hand, is milled out of a single block of ceramic and so will be missing all of this characterization.

Now there are some highly skilled cosmetic dentists who can paint on these characterizations and make a CEREC crown look more lifelike, but you’re talking about fewer than 1 in 100 dentists who can do this and have the equipment to be able to bake these colors on. And even with them, it is still not as good, in my opinion, as having the color embedded in the crown the way it is in a natural tooth.

I should mention also that this is really a job for a skilled cosmetic dentist. The vast majority of general dentists would not be this attuned to the appearance of these front teeth.

Now if you don’t mind having two front teeth that have a flat color and are fake-looking, then go with the convenience. The temporary crown that you have to wear for a couple of weeks is annoying. But I think most people would put up with that for the result of attractive front teeth.

If you opt for the CEREC crowns, you don’t need a referral from your dentist. It’s easy to find a dentist who does CEREC crowns–just search for CEREC crowns with the name of your locality also in the search box.

By the way, there are other brands of same-day crowns. CEREC is the most popular. There is also PlanScan and E4D, which use the same on-site milling technology.

We thank our advertisers who help fund this site.

About David A. Hall

Dr. David Hall was one of the first 40 accredited cosmetic dentists in the world. He practiced cosmetic dentistry in Iowa, and in 1990 earned his accreditation with the American Academy of Cosmetic Dentistry. He is now president of Infinity Dental Web, a company in Mesa, Arizona that does complete Internet marketing for dentists.

I had an awful experience getting this CEREC crown

Dr. Hall

I recently had a CEREC crown put in. I was told how great the CEREC was going to be, and that this was supposed to fit perfectly. But it didn’t seem to go that way.

I ended up spending about three hours in the dental chair. My dentist said she had to take a generic image from the database because my tooth was in such bad shape. And then the crown didn’t fit when it was made. I was watching the screen on the machine when she was making it, and I noticed a lot of red area. And then when she tried to put it on, it didn’t fit. She had to hand grind the sides and a lot off the top. It looked like it was sitting up really high and she had to grind it a lot. And then now it looks like it’s a little lower than the teeth next to it and doesn’t look like a natural tooth. It doesn’t have the bumps on it like my other teeth have, and seems a little wider on the outside at the base. Also it seems a little sensitive. I don’t know if that’s normal for a period of time or not. Its been almost a week. It just don’t feel strong. I wonder if it is not seated in properly.

Now when I went to the CEREC site, it looks like this was supposed to be a near perfect fit and would only take a few minutes to put in. And only minor modification if any. I also sen the image of how it looks when they take the image. My tooth looked identical to this, so Im a little concerned why she is saying it was because the tooth was in bad shape as to why they couldn’t fit it right or get a proper model of it. It looks from the site that they could make a copy of the top tooth to know how it would fit. But my dentist only took a image of the prepared tooth, so that doesn’t seem right.

So I want to know if my dentist did something wrong and is she trying to cover it up? and what about the sensitivity – why is that?
– Chad from Texas

Dear Chad,
You’re correct that something isn’t right with this crown. I can’t pin down from your description exactly why you had this bad experience, but you’re right that it shouldn’t have been this way.

The initial comment that your dentist made about having to take a generic image from the database because your tooth was in such bad shape–I’m not sure what to make of that. The CEREC crown system is made to deal with teeth that are in bad shape. Teeth that are in good shape don’t need crowns. The CEREC software asks the dentist to input which tooth is being crowned. For example, the dentist would program in that you need a crown on your upper left first molar. CEREC is set up to recognize how that tooth is supposed to look and gives the dentist a starting point for designing the crown. Then the images of the surrounding teeth and the opposing teeth should give her the information the machine needs to fit the crown perfectly onto your tooth and into your bite. Clearly, from all the grinding she did and what you are telling me about the shape looking funny and the tooth looking low, that didn’t happen. Why? One possibility is that she didn’t really know what she was doing. Another is that there was some problem that she didn’t tell you about such as that your gums were bleeding so badly that she wasn’t able to get good pictures of your prepared tooth.

There are a lot of things that can go wrong with a crown. In dental school, the first operative procedure your dentist was taught was how to do fillings. Only after she mastered that was she taught how to do a crown, because a high level of skill is required to do a crown and there are a lot of things that can go wrong. If the crown doesn’t fit the tooth perfectly all the way around, for example, the crown will have what is called an open margin–a gap through which decay can enter. Decay that gets into a tooth under a crown can ruin a tooth. If the bite isn’t designed correctly, it can lead to soreness in the tooth or TMJ problems. If the sides aren’t contoured correctly, it can lead to gum inflammation and gum disease. From the sounds of what you described, it seems like your dentist may have just sculpted the crown freehand in your mouth, which is a recipe for all kinds of trouble.

You mention sensitivity but you don’t say whether it is steady, increasing, or decreasing and whether that is sensitivity to cold, to sweets, to biting, or to something else. If it is steady and caused by either cold or food or air, my guess would be that is from an open margin. An open margin would probably mean the crown needs to be re-done.

You definitely want to get another dentist to look at this. And, assuming the crown has to be re-done, your dentist should pay for that. Don’t demand just a refund, but you want her to pay for the replacement crown and anything else that may be required to fix this, which may be more than what she charged you for this defective crown.

A couple of little tips on getting this second opinion–do not tell the second dentist any of this that you told me. Just tell the dentist you were questioning the crown and say that you don’t really want to say any more than that, and you want his or her opinion on the crown based alone on what he or she sees, not based on your story. Don’t give the name of your dentist. You want a blind second opinion. The more you say, the more you telegraph about the answer you’re expecting, and that can color the opinion you get. And you don’t want the dentist influenced by any friendship or animosity they may feel toward your dentist. If they press you for more information, say that you’ll be happy to share that after they tell you their opinion about what they see but not before. Oh, and be willing to pay for an x-ray so that the dentist can fully evaluate this.

Good luck,
Dr. Hall

We thank our advertisers who help fund this site.

About David A. Hall

Dr. David Hall was one of the first 40 accredited cosmetic dentists in the world. He practiced cosmetic dentistry in Iowa, and in 1990 earned his accreditation with the American Academy of Cosmetic Dentistry. He is now president of Infinity Dental Web, a company in Mesa, Arizona that does complete Internet marketing for dentists.

A dental horror story, and getting things fixed from here

In 2010 I changed going to the dentist I had gone to all my life as he was retiring. I am 62 now and I wanted to go to someone that was closer to my home. My insurance gave me a choice of dentists.

I went to my first appointment and my new dentist said I needed 4 crowns on my bottom back teeth replaced. He said they were over five years old, and they had decay. They had been on many years. Same with the four front teeth but he said he could put on whiter crowns but I would wait till the new year for more help from the insurance. I had the new crowns on my bottom teeth crowned in 2010 with CEREC porcelain and paid an extra $150.00 per tooth that they did not charge the insurance, just me. Now I find out that all porcelain crowns are usually put on just the front teeth.

Then the dental office said the front 4 were pre-authorized by the insurance. So I had all 8 front teeth prepared and got temp caps and waited for my crowns. They came back and he cemented them on. Then problems started. Besides finding out the work had not been pre authorized the back of one of my front teeth chipped off. I went in and he ground on it and sent me home. The next day half the tooth fell off. My husband left work and took me back and requested he redo both front teeth which he agreed to do. So I went back to the lab for color match again. The lab told me that they had not made any mistake on the first crowns and they were not very happy about it. So when the new crowns came in they were very thick on the backs and the dentist had to grind on them. After he ground for a while he stopped and said he could not grind anymore as it was getting too thin. So I went home and realized that everything I ate got stuck in between the two teeth. He said he would check with the lab but I would probably have to pay them to remake the crowns. I was shocked. A month went by and no word back. I finally called my insurance and they said to file a complaint. They did an investigation, sent me to a different dentist that said my bite was horribly off. The insurance finally said there was not enough evidence to show he did poor work on my front 2 teeth.

Then came a letter from my dentist that he would not see me anymore. I did not want to go back to him either but what about the problem and what about any guarantee on all the work previously done? I went on until it was time to go back for my checkup. I decided to go to a dentist that a friend went to and loved. He did his checkup and told me the blackish color on some of my new crowns was micro-leakage and bacteria under the crown had caused that. When putting on the crowns everything has to be as steralized as possible. So once again I filed a complaint with the insurance. In the meantime one of my front crowns broke off. I added to my complaint my tooth breaking off. So now I am waiting to hear back from the insurance again. This new dentist emailed his chart notes of his work. He did two root canals and crowns on my upper back teeth and he did not use all porcelain. He also included pictures of my teeth with the micro-leakage and the gap between my two front teeth and my bite being off with his recommendation. So I am waiting to hear back from the insurance and trying to decide whether or not to get an attorney involved as the insurance will only recover the money they paid if they agree with my complaint. In the meantime I have a temporary on my front tooth. This has been a nightmare. Will you please give me your thoughts on this?
– Corinne from Utah

Corinne,
If you go to a new dentist who says that all of a sudden you need a lot of work, something is wrong. Frequently, the old dentist was negligent in either not diagnosing correctly or in doing patchwork dentistry rather than comprehensive dentistry. But it could be that the new dentist is taking advantage of you. If that happens to anyone, I would recommend getting a second opinion from a dentist you know is up-to-date. Don’t rely on your insurance network – find another dentist on a private pay basis, a dentist who has a modern, clean office, that appears to be high quality, and get a second opinion and compare notes. Say as little as possible about your situation and nothing about what either dentist said. Don’t even identify the dentists, but make it clear that when you have the work done, you are going to use a dentist in your insurance network. You’re just looking for an honest opinion from a dentist you feel is up-to-date and who you know has no stake in the outcome. If you can take copies of your x-rays, do so, but remove any identification of the dentist. If you have to, just pay for additional x-rays. It’s worth it, to get to the truth.

Another problem people have is relying on dentists in their insurance network. These are not usually the best dentists. The dental insurance company usually picks them because they are the cheapest. (Read more about preferred providers here.) And while I am not in a position to say whether or not your crowns needed to be replaced, I am suspicious, from what this dentist said about the crowns being over five years old, that the dentist was merely taking advantage of a known insurance company standard that they will pay for replacement of a crown after five years, and maybe there really wasn’t any decay.

It appears that you were victimized by this dentist and all the crowns that you may not have needed and the poor workmanship. And if that is the case, I would seek some compensation from this dentist.

Here is what I would advise. Before going to an attorney, I would ask your husband to demand a refund of everything you paid and threaten, if the dentist doesn’t cooperate:
1. to go to an attorney and
2. file a complaint with the dental board.
I would also see if the dentist who examined the faulty dentistry would stand behind you on this dispute. That is key to getting any settlement from the dentist – having another dentist who can vouch for the faulty work.

If the dentist will settle with you, hopefully you can avoid going to court. But if the dentist resists, then I would talk to a lawyer.

About using porcelain crowns on back teeth, that isn’t an issue here. There are porcelains that work well on crowns on back teeth. I have a CEREC all-porcelain crown on one of my lower molars and it works fine. It depends on the strength of your bite, the position of the tooth, and the type of porcelain used.

Dr. Hall

 

We thank our advertisers who help fund this site.

About David A. Hall

Dr. David Hall was one of the first 40 accredited cosmetic dentists in the world. He practiced cosmetic dentistry in Iowa, and in 1990 earned his accreditation with the American Academy of Cosmetic Dentistry. He is now president of Infinity Dental Web, a company in Mesa, Arizona that does complete Internet marketing for dentists.

Persistent pain to biting on a new CEREC crown

Dr. Hall,
I recently received my first cerec dental work done on 3 back teeth. One of the teeth hurts when I chew as if a nerve is exposed. I cringe if I chew something just slightly crunchy e.g. popcorn. I have gone back 2 times had the tooth shaved done. My dentist explained to me that I have a cow chewing effect when I eat and that the pain was more than likely from my chew. I disagree because I have never had this problem. Do you agree with her? Or can you give me a brief explanation without seeing me as to what you think may be happening. I do not enjoy eating for fear I may hit the nerve in the tooth.
– Leigh from Oklahoma

Dear Leigh,
I don’t think your problem of pain when you chew has anything to do with the fact that this is a CEREC crown. Fitting the crown to the bite is usually easier with CEREC, because this work is done by the computer that mills the crown.

There are two likely reasons for a tooth with a new crown to hurt from biting. One is that the bite is high – you hit this tooth harder than the other teeth, which makes it sensitive. The other is that the tooth is infected. The infection can cause an inflammation of the ligament that connects your tooth to the jawbone, which makes the tooth tender when you’re biting on it, or it can even cause a constant toothache.

With two trips back to the dentist to reduce the bite, I would guess that the problem is probably not that this cown is high. So it would be time to investigate if it is infected. An x-ray of the tooth would show whether or not this is the case. However, sometimes the signs of infection are rather subtle on an x-ray, so you may need the opinion of a root canal specialist if your dentist’s diagnostic skills aren’t that sharp. The intensity of your pain as you are describing it along with the amount of time that I’m guessing has passed since this crown was done make me very suspicious that this is the case.
– Dr. Hall

We thank our advertisers who help fund this site.

About David A. Hall

Dr. David Hall was one of the first 40 accredited cosmetic dentists in the world. He practiced cosmetic dentistry in Iowa, and in 1990 earned his accreditation with the American Academy of Cosmetic Dentistry. He is now president of Infinity Dental Web, a company in Mesa, Arizona that does complete Internet marketing for dentists.

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