Cosmetic Dentistry Blog Cosmetic and General Dentistry Questions Answered

September 22, 2018

A crown or a veneer on a front root canal tooth?


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Hello Doctor Hall. About 2 years ago I had a root canal on a front tooth. I had a general dentist do the root canal. It wasn’t painful and I was very happy. He wanted to put a veneer on the tooth for a very low price. But, I decided not to do the restoration at that time.

I didn’t realize that lack of blood flow to the tooth would make it change color and about a year ago it started to change. I eventually had a porcelain crown put on by another general dentist. She filed down the tooth to a small fang and it really bothered me at the time. So far, the crown is stable. But I know these things don’t last forever. I just want to know if I was duped by the second dentist who did the crown rather than a veneer? Thank you for your time.
Gary from Florida

Gary,
I have a couple of points in response to your question.

First, about the choice of a crown versus a veneer. The simple answer that is taught in dental school to the question, “How do we restore a tooth after a root canal treatment?” is, “Do a crown.” Dental schools really don’t get into doing veneers much. So I wouldn’t say that the second dentist “duped” you—she just did what she was probably taught. But yes, it can be unsettling to have your front tooth ground down to a stub in preparation for a crown.

Here’s the explanation for that. Most teeth, when they need a root canal treatment, have an extensive amount of tooth structure missing and they really need a crown. I take it, from your initial decision to not do a restoration, that your tooth did not have extensive decay or a large break. Maybe it was just bumped in an accident. Also, after a root canal, a tooth tends to become more brittle and subject to fracture. A crown helps protect against fracture of the tooth.

But there is a difference here in the needs between a front tooth and a back tooth. Back teeth have chewing surfaces and cusps, and when you bite down, the pressure on the cusps tends to push them apart. Thus, when a back tooth breaks, it will likely split between the cusps. A crown will prevent that type of break.

Front teeth are subject to different stresses. There is no chewing surface, and the stress on a front tooth is almost all lateral. When you bite together, the lower front teeth push forward on the uppers, and the upper front teeth push backward on the lowers. Also, if you get hit in the face, the impact on the upper front teeth will be a lateral impact. Thus the most likely break of a front root canal tooth is snapping off at the gumline. A crown preparation, which will involve taking off about a millimeter of tooth structure all the way around, will actually weaken a tooth against this type of stress.

Here is a photograph of a crown preparation for a front tooth. This is a very conservative preparation. Most dentists will be more aggressive than this in removing tooth structure. But even with this conservative preparation, you can see that the natural tooth is going to be much stronger in resisting breaking off because of the thicker neck of the tooth.

photograph of a smile, showing the patient's left front tooth ground down and prepared for a crown

A veneer would leave the tooth much stronger. To prepare a tooth for a porcelain veneer, a dentist has to only remove about half a millimeter of enamel, and from the front of the tooth only. Below is a photograph of two front teeth prepared for porcelain veneers.
two front teeth, prepared for porcelain veneers, showing about half a millimeter of enamel removed

So why don’t most general dentists do veneers on front root canal teeth? With a much thinner layer of porcelain, it requires more skill on the part of both the dentist and the laboratory technician to block out the darker color of the underlying tooth. Most general dentists really don’t know how to do that.

Moving on from that point, I also wanted to make a comment about the discoloration of the tooth. It isn’t widely known that the source of the vast majority of the discoloration of a front root canal tooth is not the tooth drying out, but it comes from the root canal filling materials that are used inside the tooth. When I did a root canal treatment on a front tooth, I would clean out all the root canal filling materials from the inside of the crown of the tooth, place a white fiberglass post down into the root to strengthen the tooth, and then seal the opening I had made into the tooth using composite filling material. With that type of treatment, it could be five or ten years before any discoloration would set in and the tooth would need a veneer.

– 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.

September 6, 2018

Matching the color on a crown for a front tooth


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Hi Dr. Hall,
I had a root canal done on my front tooth over 10 years ago. In the past few years I had noticed a blue discoloration at the top of the tooth. After trying internal bleaching, my dentist ended up doing a crown.

The first crown that came back from the lab looked very white. He redid it. The next tooth, which is in my mouth now, looks better but doesn’t match the other front tooth. The dentist permanently cemented it in, but when I got home and took some selfies I was unhappy with how unnaturally white it looks.

The dentist will give it another try but my question is — should I let him try again or go to someone else who specializes in cosmetic dentistry? I now live in Princeton, NJ and my dentist is in Brooklyn. Cost is a factor.
Thanks,
Ronnie

Ronnie,
Doing a crown on a single front tooth is a tricky procedure. The slightest variation in color between the two front teeth is usually very noticeable. And it isn’t just the overall color—any tooth has multiple colors in it. Even expert cosmetic dentists will often have multiple try-ins before they get the crown to match perfectly. When I was in practice, I charged about 40% more for crowning a single front tooth because we would typically send it back to the lab three or four times until we got it perfect and I would charge the extra fee because of all the extra appointments. Dentists with poor cosmetic dentistry skills sometimes ask patients to crown both front teeth in order to get the color right.

That your dentist would think that the crown would look right after one or two trips to the lab shows either inexperience or a low level of commitment to excellent cosmetic dentistry. I’m not meaning to imply condemnation with that comment because that is typical of the overwhelming majority of dentists—maybe 98% of them. So yes, if you want this done so that your two front teeth match perfectly, you need to raise your sights and go to an excellent cosmetic dentist such as we recommend. There are several excellent ones within reasonable driving distance of Princeton, say 15-30 miles.

However, depending on how big a factor cost is for you, and if your dentist is willing to work with you to get this right for no extra charge, you may want to stick with this dentist to save the money of having another dentist start over with you. And, I would add, if you are willing to make several more trips back to Brooklyn. To help the process, you or the dentist should get hold of a good digital camera that is capable of taking a clear photograph of the new crown in place next to your natural tooth under outside light, such as right next to a window. That will go a long way toward helping the ceramist pin down the right color. And be sure that the crown is only temporarily cemented until you have seen it under various lighting conditions.

If you want perfection—a crown so natural that you can’t distinguish it from the real tooth next to it—you need the expert cosmetic dentist. But if you are willing to accept some compromise of that ideal in order to save money—try letting your dentist have some more tries to get this closer.
– Dr. Hall

Do you have a comment or anything else to add? We’d love to hear from you. Enter your comment below.

Click here to ask Dr. Hall a question of your own.

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.

February 2, 2016

Do I really need this crown on a root canal tooth?

Filed under: Dental crowns — Tags: , , — mesasmiles @ 7:38 am

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Hi, Dr. Hall,

I had a root canal done on a molar almost 5 years ago. After the dentist did the canal he put in a filling which has recently come out. I went back and he has told me I need a crown put in with posts, I was wondering if this is necessary rather than just getting another filling? What are the pros and cons of crowns? and is it strange that he didn’t originally put in a crown as there’s not much of the tooth left and I think he probably would’ve known the filling wouldn’t last. Any help would be great as I really don’t know what to do.
Thanks,
Melissa from Ireland

Melissa,
The only puzzling part of your situation is why the dentist didn’t recommend a crown when the root canal was first done. Now you’re in Ireland where much of the dental care is publicly funded. I’m wondering if that has something to do with this.

Not every tooth that has a root canal treatment needs a crown. I’ve written before on this blog about the need to be careful in doing crowns on front teeth that have root canal treatments, as a crown will weaken a tooth against lateral stresses. But practically every molar with a root canal treatment does need a crown. The reason is that once a tooth has a root canal treatment it tends to become more brittle over time and more susceptible to breaking. Molar teeth in particular are the most susceptible of breaking in this circumstance for two reasons. They are the teeth furthest back in the mouth, so they receive the greatest chewing pressure. Furthermore, because of their cusps, the stresses on them tend to separate the cusps, which subjects them to a high risk of cracking in two. A crown will protect the tooth against cracking in two.

So yes, I would do the crown.

And a post or posts would be needed if there isn’t much of the tooth left to hold the crown on—if the tooth is mostly filling. Otherwise you wouldn’t need a post.

– Dr. Hall

Do you have a comment? We’d love to hear from you. Enter your comment below.

Click here to ask Dr. Hall a question of your own.

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.

August 29, 2013

There are a lot of things that can look like decay on the x-ray under a filling. Be careful here.

I have had a filling in the back of my lateral incisor (#7) since childhood that has been replaced several times over the past 10 years due to leaky margins, etc. The last time it was filled was in January of this year when my then dentist placed a pulp cap to avoid a root canal. There was minimal bleeding and he used a caries detector with dye to remove any caries by hand to avoid drilling too close to the pulp and then filled it.

I did not have any discomfort to hot or cold or any pain afterward. I still do not have any pain in this tooth on tapping or when eating and it feels fine but it was discovered at my new dentist that there is what looks like some decay under the filling on x-rays during my last exam in June with my current dentist and she says I have to have a root canal and a crown placed.

My question would be; if there is no sensitivity/discomfort in this tooth, would it be possible to remove the filling, clean out the decay and then place another filling or do I have to accept the root canal/crown diagnosis? I have already researched and contacted Dr. Hurley in Bedminster for the crown after finding her on your provider list for New Jersey, but would of course like to postpone the “bigger” treatment if possible. Thank you so much in advance for your attention and advice and I love your very informative website.
– Kathryn from New Jersey

Kathryn,
I’ll go a step further even beyond your suggestion of waiting to have this root canal done. And I’ll be direct. No, I would not have this new dentist do a root canal and crown on this tooth. It sounds to me like they are a little too eager to do something quite aggressive here. Have another dentist look at this.

It’s interesting how you put the diagnosis – “It was discovered that there is what looks like some decay under the filling on x-rays during my last exam.” There are a lot of things that can “look like decay” on an x-ray. An empty space, a radiolucent glass ionomer base, or any of a number of radiolucent filling materials can “look like decay.” If the filling looks intact and isn’t leaking, after a close visual exam, I would leave it alone. If the tooth is infected, it would show up on an x-ray of the ROOT of the tooth.

A tooth that becomes infected will almost always hurt at some point, though there are exceptions. It will start by being sensitive to cold and ordinarily that will blossom into a full-fledged spontaneous toothache. The toothache, if untreated, will go away, and the tooth will die, after which it will usually become sensitive to biting on it. But that may not happen. It is uncommon for a tooth to die quietly, with no symptoms, but it does happen. The way to diagnose that is not by seeing something that “looks like decay under the filling,” but by seeing signs of infection around the end of the root of the tooth on the x-ray.

Finally, this idea of doing a crown on a lateral incisor after a root canal – I would not let them do that, even if it DOES need a root canal. A lateral incisor is a very thin and delicate tooth. To prepare a lateral incisor for a crown, most of the tooth structure has to be removed, leaving it very weak and vulnerable to breaking off. The average lateral incisor is going to have a diameter at the neck of the tooth of about 5 millimeters. To do a crown, at least a millimeter has to be ground off all the way around, leaving it with a diameter now of about 3 millimeters – which represents a decrease in resistance to lateral fracture of more than 60%. So, even though a back tooth with a root canal treatment needs a crown to keep it from fracturing, a front tooth is a completely different situation.

Now, if you don’t do a crown on a front tooth after a root canal, it will be susceptible to discoloration. But that susceptibility can be decreased and postponed by several years by careful handling of the tooth after the root canal. If all the root canal filling material is cleaned out of the part of the tooth that shows – carefully cleaned out inside down to the root of the tooth. Then, a translucent post can be placed in the root canal space to reinforce the strength of the tooth. If that is done, it could be five or ten years before the tooth shows any signs of discoloration, and you could do a crown then.

And furthermore, if you are going to have a single porcelain crown done on a front tooth, you definitely want a dentist with good artistic ability, such as Dr. Hurley, to do it.

– Dr. Hall
follow up: The next day, Kathryn sends an x-ray of the tooth, and I offer my opinion. It appears that this tooth does not need a root canal treatment. There is a dark area next to the tooth, but it doesn’t extend near the pulp, and there are definite signs that the root is healthy.

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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