Cosmetic Dentistry Blog Cosmetic and General Dentistry Questions Answered

June 20, 2019

My crown on my front tooth isn’t staying on


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Dr. Hall,
I read your last answer about the crown not staying on. I have a root canal in tooth # 10 (upper left lateral incisor). The crown stayed on for about ten years. Then, about 1 1/2 years ago, my dentist replaced it. During the time since the new crown was placed, it has come off several times and been recemented. It never has felt really secure. Do you think there is hope for the crown to stay on if re-cemented? There isn’t really much to cement it to.
Thanks, Evelyn from California
 
Evelyn,

There should be a way to get this crown to stay on better. The problem is probably in the design of the crown preparation, and not in the strength of the cement or bonding material. If that’s true, it would mean you need a new crown for this to stay on. That’s just a guess. But let me give you an explanation of what can be done when a tooth has had a root canal treatment and there isn’t much tooth left to hold on to.

I wrote in an earlier post that the main reason crowns come off is that they aren’t prepared with proper retention form. Now, if there isn’t much tooth structure left, it isn’t possible to properly prepare the tooth. So what I would do to improve the retention would be to cement a fiberglass post deep into the canal. It needs to be a post with some flexibility to it, or under the stress of oral function the post could fracture the tooth root. I would then bond to the tooth and the post some core material.

Here are photographs of a case of a crown on a front tooth in a situation like this, courtesy of the dental journal Dentistry Today.
close-up photo of a broken down lateral incisor tooth with a fiberglass post fitted into the root canal spaceIn this first photograph, some of the root canal filling material has been removed and a fiberglass post is fitted into the canal. The post needs to go deeply into the tooth, but not so far as to require removal of all of the root canal filling material. About 2/3 of the length of the tooth would be good.

A close-up photograph of the same lateral incisor, with core material added and the core trimmed into a crown preparation.Then the post is bonded into the canal and a core material is built up. Composite is usually used for both the bonding of the post into the canal and the core. That composite is then shaped into a conventional crown preparation as shown here.

Built up like this, the tooth should be able to retain a crown easily. I will note that there has to be some tooth structure remaining. The amount of tooth remaining in this case is about the minimum amount needed. If a front tooth, say, is broken off level with the gums, and the retention has to come completely from the post, it won’t work. Normal oral function will create twisting stresses on the post and will eventually dislodge it.

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.

May 16, 2018

Will my electric toothbrush loosen the post in my tooth or the crown?

Filed under: Uncategorized — Tags: , , , , — mesasmiles @ 11:06 am

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Hi Dr. Hall
On your page about how to remove a post in a tooth you mention that an ultrasonic tip can be used to help remove a post. I have a crown on a post and want to use an electric toothbrush. Is there any chance that an electric toothbrush can cause the crown falling off or post loosen up due to the vibrations?
– Anna

Anna,
Many of today’s electric toothbrushes use sonic vibrations through the bristles to help loosen plaque. I don’t believe these are strong enough to loosen anything that is cemented in your mouth.

The ultrasonic tip that a dentist would use to help remove a dental post cemented in a tooth would be the tip of an ultrasonic scaler—a powerful tool used by dental hygienists to help clean teeth. The tip is rigid and imparts the full strength of the ultrasonic vibrations to whatever it touches. When used to remove a post, it has to be pressed firmly on the post for an extended period of time.

By contrast, the vibrations of a sonic or ultrasonic toothbrush are transmitted through the soft bristles and thus are very gentle.

– 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.

May 3, 2018

Whose fault is it that this tooth broke off?

Filed under: Fractured teeth — Tags: , , , , — mesasmiles @ 9:41 am

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Dr. Hall,
I had a crown put on tooth #7 (right lateral incisor) about 40 years ago but no root canal. My dentist said I now need a root canal on that tooth due to decay under the crown. I’ve had no pain, abscess or any indication of infection. The dentist attempted a root canal through the back of the crown and after 2 hours he gave up and said the canal is calcified and he is unable to locate it. He put a temporary filling in the crown and said I will need an endodontic specialist to perform the root canal. Because I am not in pain, the endodontist booked me an appointment 4 weeks out. Well it’s been 2 weeks and now my crown (with some tooth inside) has broken off and I don’t know what to do. I’m elderly and can’t spend a fortune on this tooth issue when it probably should have been left alone in the first place. Should I just get an implant? Attempt a root canal? I doubt there is enough tooth left to put a new crown on even if the root canal is successful. I bought some DenTek at the drug store today and can reattach the crown myself. I would greatly appreciate your perspective on this.
Ruth

Ruth,
I’m going to start by trying to answer a question that you were too polite to ask: Whose fault is it that this tooth broke off?

Your dentist was drilling inside this tooth for two hours looking for the root canal and not finding it. It’s hard not to believe that doing so seriously weakened the tooth and is the reason it broke off. And having done that, he didn’t pass that information on to the endodontist or do anything in the meantime to strengthen the tooth. Hopefully he has learned a lesson from this, but meanwhile you are victimized here. It seems reasonable to me that he should accept some of the responsibility for the fix you are in.

With there being decay under the crown, the logical way to proceed here would seem to me to be to take the old crown off (it will have to be replaced anyway), get rid of the decay, and then finding the canal would be much easier. If the tooth really got infected, then the decay penetrated into the canal. But even if it didn’t, having the crown off greatly increases visibility and access.

Meanwhile, to answer the question you actually asked, if the tooth is down to a stump then yes, it may be difficult to put a crown on it and you could lose the tooth and need an implant. However, if your bite isn’t particularly stressful, the right kind of dental post in the tooth could enable it to hold a crown, even if there isn’t much of the tooth left. But after the fiasco you’ve been through, I’m doubtful that your current family dentist has enough expertise to pull that off. The placement of the post or posts would need to be done in such a way as to brace the restoration against rotational forces, and that can be tricky. Posts are round and lateral incisors are kind of round in cross section, and it doesn’t take much twisting force to loosen a crown and post in this situation.
– 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.

January 24, 2018

The filling in my root canal tooth came out

Filed under: Root canals — Tags: , , , , — mesasmiles @ 6:10 pm

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Dr. Hall,
So it might sound a little crazy, but I had a root canal done a few years ago. Since then I haven’t been to the dentist, and can’t currently go due to financial problems and no health insurance. Since it’s been so long the cap or synthetic tooth, has fallen out and is now revealing a metal rod. The rod seems to be moving back and forth. What would be my best option? Can I remove the metal rod myself? Should I just leave it till it falls off or till I can get to a dentist?
Heather from Pennsylvania

Heather,
You really need to go to a dentist for a simple replacement of the temporary filling material. And knowing that your finances are strained, you may be able to talk some compassionate dentist into doing this very cheaply or even for nothing at all. Goodness, a dental assistant could do this for you—just get some Cavit and plug it into the hole. Otherwise, you’re going to lose this tooth. Cavit is a simple temporary filling material that comes out of the tube as a paste but when placed in a moist environment like your mouth it hardens. Since it requires no mixing or tray of tools, it can be placed in a few seconds.

When a tooth has a root canal treatment, the root canal filling material then needs to be protected against the oral fluids. Otherwise, saliva will seep down and loosen that root canal filling, which allows the tooth to become re-infected. This causes failure of the root canal treatment. The tooth would then need a new root canal filling in order to save it. So the dentist will put in a temporary filling and then plan when to finish the treatment of the tooth, probably protecting it with a crown.

When I was in practice, knowing that some patients could get into your situation and not come back for the crown, I would fill the tooth with a bonded core material, often using a metal post. If they didn’t get back right away, this would hold up for several years. Maybe something like that has been done in your situation. If the metal post is still present, hopefully there is still time to save the root canal treatment, but the hole needs to be sealed.
– Dr. Hall

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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.

September 16, 2017

I have a titanium allergy and think I have a titanium post in my tooth


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Dr. Hall,
I have recently been diagnosed with a titanium allergy. I have two crowns on my left side, upper and lower. I have various odd symptoms that have been addressed with my dentist. They have been checked out and I’ve been told everything “looks” fine. The dull ache surrounding my upper remains. I’m wondering if I have a titanium post and if this is possibly contributing to this dull ache and possibly other unexplained ailments throughout my body. Where do I go from here?
– Jennifer from Kentucky

Jennifer,
Titanium allergy used to be considered very rare, but with the increasing use of dental and orthopedic implants, which almost always use titanium, there are increasing reports of titanium allergy. The MELISA Medica Foundation, which conducts the MELISA test for metal sensitivities, estimates that as many as 4% of the population could be allergic to titanium. However, this test has been criticized as generating false positives, and my guess would be that titanium allergy is less prevalent than that.

Titanium is a very biocompatible metal, apparently due to its high corrosion resistance. Given this corrosion resistance, I would not think that the presence of titanium in a post inside of a tooth would affect tissues outside of the tooth, but I guess that would be possible. If you want to investigate that, I would just go to the dentist that put the post in your tooth and ask if it is titanium. Your dentist should have a record of the type of post that was inserted. I will add that there should only be a post in your tooth if the tooth has had a root canal treatment.

Metal posts are often used in root canal teeth to help retain the buildup that is placed in the tooth and the buildup in turn helps retain the crown on the tooth. For many years, stainless steel posts were the standard. Stainless steel contains nickel, and it is estimated that 10 to 20% of people are allergic to nickel. It was assumed that this wasn’t an issue, because the post was sealed inside the tooth and not in contact with living tissue. Then, about 30 years ago, it was discovered that corrosion products from the stainless steel could leach through the teeth and many dentists, including me, switched to using titanium posts.

Could your dull ache be from a metal sensitivity? I would say that it could. I would wonder if there is any metal in the crowns you have—that is something worth checking also. There could also be a problem with the occlusion of the crowns. In any of these scenarios, everything would “look fine,” but that doesn’t mean that everything actually is fine.
– Dr. Hall

Do you have a comment or a question 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.

April 26, 2017

My dentist put a screw post in my front tooth

Filed under: Root canals — Tags: , , , , — mesasmiles @ 11:58 am

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Hi Dr Hall,
I just had a front right central incisor break at the gumline after getting a root canal treatment. My dentist has used a metal screw post for the temporary crown. I have a continuous dull feeling in nasal cavity area but no pain. Is the screw a good idea for this type of problem as I cannot afford a bridge?
Many Thanks,
Frank from Pietermaritzburg, South Africa

Frank,
These screw posts generally are pretty solid as far as staying in the tooth, but they are risky. They exert a lot of stress on the root. The risk is that the root will split from the pressure. Is that happening in your case and is that why you have this dull feeling in the nasal cavity (which would be where the end of the root of this central incisor would be)? That could be, but I would wait it out.

But a front tooth that has broken off at the gumline is a tough situation. Many dentists would consider the tooth to be unrestorable. There are rotational forces on a front tooth that over time can loosen the crown and/or the post. My advice would be to go ahead with the crown, cross your fingers, and hope this post and crown last a long time. My guess would be that they would fail at some point.

If you can’t afford a bridge, the budget option for replacing a single front tooth would be a flipper partial. That may be where you end up.

In retrospect, it would have been good if your dentist had placed a simple post in your tooth after the root canal treatment, before the tooth broke off.

Dr. Hall

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

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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.

August 29, 2016

Removing a metal post in a tooth


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Dr. Hall,
I just found out my dentist inserted a stainless steel post into my root canal tooth–my upper molar. A temporary crown is placed over it now and a permanent crown will be placed in a week. My question is can the post be removed and a zirconia or carbon post (I don’t think he does those) be put in instead? I don’t want steel in my mouth even though he said it’s encased. My ears have been pulsating since. Please tell me it’s removable!
– Linda from Brooklyn

Linda,
Yes, a stainless steel post probably can be removed, though there may be some risk involved.

Let me give a little background on this to frame my answer.

stainless steel dental post

A metal post in a lower molar

When a tooth is “bombed out,” needing a root canal treatment and with little tooth structure left, a dental post is often placed in the tooth. This post can serve a couple of purposes. For front teeth and premolars, it can strengthen the tooth against horizontal fracture. For molars and any other teeth, it can also provide additional retention for the crown. If there is little of the original natural crown of the tooth left, the post, anchored in the root of the tooth, will help retain a buildup in the tooth, and the buildup retains the crown.

There is a history to the material out of which the post is made. In the 1970s and earlier, stainless steel was the material of choice for prefabricated dental posts. However, in the 1980s it was discovered that even though a post is cemented inside the tooth and doesn’t come into contact with the bloodstream at all, metal ions were found to leach through the tooth and into the bloodstream. Stainless steel contains nickel, which causes sensitivity reactions in many people (see some of our blog posts on metal allergies). To guard against potential reactions as you seem to be experiencing, many dental practices, including mine, switched to titanium, which is not only very strong but the most biocompatible metal available. In the 1990s, other materials were introduced for posts, including carbon fiber and fiberglass. More recently, zirconia has been used for posts. Zirconia is a ceramic that has high flexural strength and is also very biocompatible.

So yes, you have a legitimate concern about this stainless steel post. Your dentist should get with current technology. From what you are telling me, he isn’t into any of these newer post materials, most of which have been around for twenty years or more.

Now, as to removing the post that is in there, that could be tricky and, depending on the situation, you may not want to trust your dentist to do this but may want to see a root canal specialist or another dentist who feels comfortable doing this. It depends on how deeply the post goes into the root of your tooth and how well it is cemented. It may be possible to dislodge it with an ultrasonic tip. I remember one patient I had who was adamant about removing several metal posts in his teeth. I don’t remember why his posts were so difficult to remove, but I ended up telling him that I had to drill out all of these posts and I had him sign a paper acknowledging that I had told him there were serious risks in doing this, that I could perforate the roots of any or all of these teeth, leading to the loss of the teeth. He was willing to accept those risks. The good news is that I got out all of the posts without any accidents, but I remember it was very stressful for me.

If you feel that you are experiencing a sensitivity reaction to the post, I would put a halt to the crown procedure until you can have the post removed. Cementing a crown on the tooth will only make it more difficult, as your dentist would have to start by drilling through the crown, possibly ruining the crown.

Dr. Hall

Do you have a comment or a question 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.

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