Cosmetic Dentistry Blog Cosmetic and General Dentistry Questions Answered

March 7, 2019

All ceramic vs porcelain-fused-to-gold crowns


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Dr. Hall
I am having crowns replaced over tooth number 4 & 5. There is, as I believe, no cosmetic value of using pure porcelain versus Crown Porcelain fused to High Noble. There is a significant extra cost of $200.00 per each pure porcelain. In general, would a pure porcelain fused to a High Noble versus pure porcelain be just as effective over the long term?
– Garry from California

Garry,
First, I like to talk about terminology so we know exactly what we are talking about. We should be saying all-ceramic crowns, not all-porcelain. Porcelain is only one of various ceramics that have been used for crowns and even some dentists gloss over this terminology. Few dentists are placing all-porcelain crowns on back teeth these days because they are very technique sensitive and are much weaker than the newer high-strength ceramics, lithium disilicate and zirconia. The eMax crown, which I believe is the most popular crown being used by dentists today, features a lithium disilicate core with porcelain baked over it. Lithium disilicate has reasonable aesthetics—it is white and somewhat translucent—but it comes in blocks and is shaped by milling, so the technician doesn’t have the ability to manipulate the color the way porcelain color is manipulated. Porcelain comes in a paste and it is placed, shaped, and then baked. So the ceramist can apply various colors and translucencies of the paste in different layers over the lithium disilicate core with a great deal of control over the aesthetics.

My guess would be that your dentist is talking about putting all-ceramic crowns on your teeth numbers 4 and 5, which are the first and second premolars on your upper right. So your question is, should you get porcelain fused to high noble (otherwise called porcelain fused to gold) instead.

Cosmetic dentists consider upper first premolars to be in the smile zone on almost all patients. Practically everyone will show that first premolar prominently when they smile. It may not be prominent when you look at yourself straight on in the mirror, but it is very noticeable from the side. For me, I would not want a crown made of porcelain fused to gold or any other metal here because there will be a significant risk of a dark line showing at the gumline. The dark line comes from the metal foundation showing through right at the margin of the crown.

Behind that first premolar, in my smile, the teeth are all in the shadows, so the aesthetics is much less critical there. In my mouth, I do have a porcelain fused to gold crown on one of those teeth. I also have a crown on my upper left first premolar, and that crown is an eMax.

So my answer is that I disagree that there is no cosmetic value here. Having said that, if you were my patient and wanted the porcelain fused to gold crown on your first premolar, I wouldn’t fight you on that. But then I probably wouldn’t have the issue come up because I would charge the same fee for either crown. A porcelain fused to high noble crown is a premium crown, and I charged more for that than for a porcelain fused to noble (semi-precious metal) crown. But I don’t understand why the all-ceramic crown needs to be more than the porcelain fused to high noble.

– 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.

February 22, 2017

Should I get a radiolucent crown or a radiopaque crown?


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Hi Dr. Hall,

I came across your blog and read your very interesting response to a writer with root canal issues. I, too, seek your advice.

I had my lateral and central incisor teeth filed down for a bridge (missing the two teeth in-between). I changed my mind from having the bridge when I learned about some negatives surrounding it, and went back to the partial denture. I have been wearing the temporary crowns for almost 6 months now.

I ended up having to do a root canal on the central incisor and I have been told that the lateral will also need a root canal because it has been exposed for too long and I am getting sensitivity to cold. I am not keen on doing another root canal.

I read about pulp cap in your blog. That’s interesting. Does this need a special dentist to perform?

Could you also tell me which dental crown is radiolucent? I was interested in the eMax crowns (lithium disilicate) but I read that it is radiopaque and as such will block xrays and disallow evaluation of the tooth underneath over time. Could you please tell me if this is so? And if this is so, could you tell me which is the best material for my now vulnerable teeth. I have a lot of anxiety that I might lose them.

Thanks very much for your response.

Marcia

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Dear Marcia,

I hope that you aren’t trying to micro-manage your dentist and make all these clinical decisions for him or her. One thing I worry about in providing all this dental advice is that patients, thinking now that they are armed with sufficient knowledge, will try to tell the dentist what materials to use or will obsess over these decisions. I hope you’re not doing that. When you tell me that you have been wearing temporary crowns for 6 months and have all this anxiety I want to tell you to let go and let your dentist make these decisions. Do the best you can with the knowledge that I provide here to find a dentist you can trust and then trust him or her.

It sounds like you’ve been stewing over these decisions, wearing these temporary crowns for so long, and now one of the teeth became hypersensitive and needed a root canal and another is getting that way. It surely is time to let your dentist finish your case.

You’ve latched onto this question about whether a particular crown material is radiolucent or radiopaque and have decided that you want a radiolucent crown. But you don’t know enough to be getting into the weeds this deeply. There are a number of factors that go into selecting a material for a crown, and you have a very imperfect understanding of even this one factor.

But since you asked, let me explain a little about this issue.

Radiolucency of Crown Materials.

The only type of crown that is radiolucent is a plastic crown, which would be used as a temporary crown. A radiolucent crown is one that doesn’t block the x-rays at all. So yes, you are right, that with the x-rays you can see right through it. The problem is that decay is also radiolucent. Decay would tend to start at the margin of the crown, and with a radiolucent crown it would be impossible to tell for sure what is decay and what is just part of the crown.

But, you say, a radiopaque crown blocks the x-rays and so you couldn’t see under it. Here’s where oversimplification is getting you into trouble. There are many degrees of radiopacity. The ideal would be to have a crown that is partly radiopaque, just like tooth structure is. It doesn’t block the x-rays completely, only partially, so you can see through it to a certain extent but it doesn’t look just like decay.

To illustrate, here is an x-ray of a patient showing four types of crowns plus composite filling materials, and you can see the variations in radiopacity. None of the restorative materials used are radiolucent, for the reason I gave above—radiolucency causes the most complications for diagnosis.
radiolucent and radiopaque crowns
On the upper, starting with the canine on the left, we have a composite filling that is partly radiopaque. Next, on the premolar, is an eMax crown. Yes, it is radiopaque, but it has a very helpful partial level of radiopacity that makes it easy to tell what is going on with the tooth. Next, on the first molar, is a porcelain fused to metal crown. True, you can’t see through it, but you can see what is happening on the margins, which is where you would expect recurrent decay to start. Finally, on the second molar, is a gold crown.

On the lower, the premolar has a composite filling, the first molar has a CEREC crown which is made of lithium disilicate, and the second molar has a gold crown.

My preference for crowns on second molars is gold, even though it is totally radiopaque. I have heard many dental educators and researchers state the same preference. I’m not going to go into all the reasons here for that choice. I only want to make the point that this radiopacity is not a simple cut-and-dried issue nor is it the only factor to be used in the choice of a crown material.

– 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.

February 11, 2016

She can’t floss after getting porcelain veneers

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Dr. Hall,
I have just had 9 eMax veneers fitted one week ago. I use Oral B Pro Expert toothpaste which dentists in the UK highly recommend for tooth hygiene. Is this toothpaste okay for my veneer care? Also the way my dentist has placed the veneers on I can’t floss in between so I have used Phillips Airfloss to clean gums.
– Michelle from Derby, UK

Michelle,
Before I address the toothpaste, which is a minor matter, the thing you need to be most concerned about is that you can’t floss between your teeth. This is a serious problem. In my opinion this is a serious deviation from the standard of care. At least you are using the Phillips Airfloss to try to clean between the teeth, but this isn’t as good as flossing. You should not only be able to floss between each of your front teeth after getting porcelain veneers, but that floss should glide smoothly along the surface of each tooth, with no snags or rough spots, clear into the sulcus of the tooth.

Without this, your gums will be puffy and not healthy. This is one of the critical things I look for when I examine photographs of the work of cosmetic dentists that I recommend on this website.

Were your veneers made by the laboratory this way? Or did your dentist simply skip the step where the excess cement is cleaned off?

There are situations, such as with advanced gum disease or creating support to hold in a bridge where some front teeth may need to be bonded together in order to strengthen them. But to create that situation for an aesthetic procedure is something I would consider completely inappropriate.

Correct Porcelain Veneer Bonding Technique

Here’s an explanation of a typical method of bonding on porcelain veneers, which I used, and which I believe is pretty much accepted technique among cosmetic dentists, or something very similar to this. After priming the surface of the tooth with the proper etching and bonding agents, I would place the bonding composite in each veneer individually and then press each veneer onto its corresponding tooth, which would cause excess composite to squirt out the sides. I would then remove much of the excess composite with a cotton roll and then begin to cure the bonding composite. This composite is light cured, and dentists use a special high-intensity curing light that emits a particular wavelength chosen so that it activates the hardening agent in the composite. porcelain veneer bonding technique small tip curing lightBut rather than cure the entire tooth, I would use an ultra-small light tip (a 2-mm tip is shown here) so that I would cure only the composite in the center of the tooth. This would tack the veneer in place so that I could floss around it without dislodging the veneer. After thus tacking all the veneers into place, I would carefully floss around the teeth, making sure that all the excess composite was removed and we were left with smooth surfaces between all the teeth.

porcelain veneer curing light large tipOnce that was done, I would go back with a larger curing tip, similar to the 13-mm tip shown here, and cure all of the remaining composite, so that the veneer was solidly attached to the tooth. Then I would finish the case by going between the teeth with fine polishing strips, leaving everything with an ultra-smooth polished finish.

Dentists who don’t do a lot of porcelain veneers may not stock this ultra-small curing tip. Not using a tool like this means a lot of extra work, because cleaning off the excess composite once it is hard is time-consuming and laborious. Of course, if they just skip that step, it’s quick and easy.

The first step I list on my page about how to take care of porcelain veneers after they are placed is “brush and floss faithfully.” If you don’t do that, you risk getting decay around the edges of the porcelain, and you risk losing the teeth to gum disease. Not good.

So I would go back to this dentist, share what I have given you here, and see if he or she can fix this so you can floss. Meanwhile, continue using your Phillips Airfloss–it’s better than nothing. But be sure you don’t put a mouthwash in it that contains alcohol. Alcohol softens the bonding composite around your veneers.

About your toothpaste, I would disagree with your dentists in the UK, that Oral B Pro Expert toothpaste is anything special for general dental hygiene. I don’t believe there is any toothpaste that is anything special for general use. I look at the ingredients in the Oral B toothpastes and I see stannous fluoride, which other toothpastes have. It’s a fluoride compound. I actually think that sodium monofluorophosphate is a better ingredient for delivering fluoride, but stannous fluoride is okay. Some of the Oral B formulas have tartar control agents, which other toothpastes also have. Some formulas have whitening agents, but other toothpastes have those and they don’t really work anyway. Some have antibacterial agents, which, again, are present in other toothpastes. Nothing unique or special here.

There are two toothpastes that are specifically designed for maintaining cosmetic dental work. One is Rembrandt toothpaste, which uses aluminum oxide as an abrasive, which is especially gentle. The other is Supersmile toothpaste, which cleans the teeth with an enzymatic action that actually dissolves the protein pellicle to which the stains attach. Because it is so gentle and thorough, that is my recommendation for maintaining cosmetic dental work, and when I placed a set of porcelain veneers, I started each patient off with a complimentary tube of Supersmile.

If you learn anything more about why your dentist made it so you can’t floss between your teeth, I’d love to hear from you.
Thanks,
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.

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