May 062015

Short Answer: 24-karat Gold, Grade-1 Titanium or Zirconia (in certain cases)

Long Answer: There are many materials crowns and fillings can be made from: Fillings, for example, can be made from a composite resin (basically hard plastic), amalgam (mercury metal filling), porcelain (there are many types) and cast metals (gold or non-precious alloys). But with so many to choose from, the “best” one depends a lot on your budget, tolerance for things not-white in your mouth, patience for longer or multiple appointments and priority placed on the “healthiest” materials. This post focuses on the latter, but I will briefly address the pros and cons of the other materials. Incidentally, crowns can be made from the same materials as fillings, but typically they are made of porcelain or a gold alloy fused to porcelain (also known as a “porcelain-fused-to-metal” crown). Here is a brief and quick summary of the different materials available:

Materials ComparisonThis post could literally go on forever in order to cover the full scope of the available materials. For practical purposes, I will say that the healthiest materials to put in your mouth continue to be Grade-1 titanium (the kind dental implants, artificial joints, etc are made from) and pure gold. This is based on many studies that show the level certain metals have on cell health (cytotoxic) and what kind of immune reaction they illicit. Gold and titanium are generally the gold standards (yes, pun intended) for bio-compatible materials.

As for gold crowns, it is quite rare to have one made out of pure 24k gold. This is because gold is soft and pliable and it would be hard to work with and would wear very quickly in the mouth in a pure form. So usually gold is mixed with other metals, most often they are palladium, silver, copper, zinc, iridium, platinum and more. Depending on the actual content, a dental metal is classified as being “high noble, titanium, noble or a base alloy”. See below:

Alloy comparison

The chart above shows metals in the order I would choose when having crowns in my own mouth (when purely considering bio-compatibility). Although high noble alloys are at least 40% gold, I generally recommend alloys that have more than 60% pure gold. Naturally, this is expensive to make when compared to other options. But the more gold in an alloy, the less there is of “other” metals. Titanium would be my next choice and I would forgo noble and non-precious alloys. Many people get what are known as “PFM” or “porcelain fused to metal” crowns which are basically thin gold crowns covered with a white porcelain material. Most porcelains are generally safe although they may contain aluminum oxide and even heavy metals (such as cobalt, barium or cadmium). The main disadvantage of a PFM is that the porcelain coating can break off the gold center piece over time. Also, the porcelain is abrasive and hard which causes teeth that oppose it to wear faster than normal. So, if a gold/metal crown was not an option, I would select a pure zirconia oxide material as the most bio-compatible of the porcelains. Zirconia is very strong and has been found to be highly bio-compatible in many studies and some dental implants are now being made of the material (a good sign that the body tolerates it well).

But sticking to the topic of metal crowns, when it comes to dental billing, some unscrupulous dentists will charge you and your insurance for a “high noble” crown but then have the laboratory make one using a lower grade and much cheaper metal. Some dentists even have a laboratory in China or other foreign country make their crowns, places where it is extremely difficult to verify what they are actually making the crowns from.  To make matters worse, some laboratories will actually tell an honest dentist they used a high noble metal, when in fact, they did not. All this happens for obvious reasons and it happens more than some people think. That’s because it is is extraordinarily hard to know for sure what it is you got without testing it and it’s extremely easy to fudge the truth. I wish I had some easy foolproof way to detect this type of fraud, but it is very difficult. Some people who are sensitive to base metals will develop gum irritations around the crown edges and this might be a sign of a problem. Also, color alone is not an indicator because even crowns with hardly any gold at all can be made to look gold in color.

Ultimately, you have to trust your dentist and make it very well known that the subject concerns you. Fully expect to get a high noble metal crown if that’s what you or your insurance is paying for. I would also recommend asking your dentist where the crowns are made, and at minimum, I would insist on a US-based laboratory. I personally charge a little extra if a patient requests a crown with gold content beyond 60% because my costs go up accordingly, but the conversation is always open and honest.

So to answer the original question, I don’t think any one thing to put in your mouth is perfect except for your original enamel. But if a crown is required, ideally it would be made from a high noble alloy with more than 60% gold. If a white crown was preferred, I would select a zirconia material.

Nov 092014

Short answer: Mostly no, but keep in mind there are dentists who recommend a root canal even when the justification is dubious.

Long answer: There are many different reasons teeth need root canals but the most common reason is that the tissues inside the nerve canals die (become necrotic). Typically this can happen due to trauma (your tooth was injured by a fall or even from the trauma of a dental drill during routine dental work), a deep cavity infected it, the tooth has severe gum disease which spread to the nerve tissues or the dentist sees signs the tooth is melting from the inside (a very rare event called “internal resorption”). Once a tooth’s nerve begins to die, there are often symptoms associated with it and this is commonly known as a “toothache”. Occasionally, there are no symptoms at all and the dentist simply finds an issue detected only in an x-ray. If any of these legitimate reasons are present, it is a good idea to have a root canal done. Some people have cited health reasons to NOT have a root canal done even when one is justified (like severe pain). They believe root canals can poison your body or leave some infected tissue behind which can lead to long-term medical problems. Suffice it to say that I believe a properly done root canal is a medically sound procedure which is beneficial to you when it is reasonably necessary, with the only alternative being the removal of the affected tooth. I say “reasonably necessary”, because there are dentists who believe in doing root canals prophylactically under certain circumstances.

“Prophylactic” root canals are those root canals done to facilitate some other dental procedure. For example, some dentists believe that when a tooth needs a dental crown (the covering placed over a tooth), it should always get a root canal first. Proponents of this believe doing a root canal is justified for a variety of reasons. Sometimes it is so a retaining post can be placed deep inside the tooth to better hold up the crown ultimately glued to it. Some dentists also believe it is best to do a root canal before any crown is done on a tooth or even just to make an otherwise sensitive tooth not sensitive anymore. There are rare cases where these situations are justified, but I do think they are very rare. I do not believe a tooth should have a root canal procedure unless it is absolutely indicated (pain, obvious x-ray signs, a cavity is followed into the nerve by a dentist doing a filling, etc.) and no other alternatives are available besides removing the tooth. This is why I would never recommend a root canal to a patient simply so that I can place a post inside it and I would certainly not recommend it prophylactically as an adjunct to a dental crown. Each case is different, but I have not discovered any justification for these types of latter root canals and a second opinion is advisable if your dentist cites these reasons as justification. The best rule of thumb is if your tooth has absolutely no symptoms and your dentist recommends a root canal, ask lots of questions. If you are not satisfied with the answers or your instincts are nagging you, get a second opinion. Remember that a lack of symptoms does not mean a lack of problems, so don’t assume your dentist is lying to you just because you can’t feel anything.

Nov 042014

Short Answer: No

Long answer: There are many reasons not to replace fillings that are intact and functioning properly. For starters, there is some risk to every dental procedure. Every time a filling is removed, there is a risk the tooth will fracture, will become sensitive or have other long-term issues. Secondly, metal fillings have been time-tested and proven to be reliable extremely long-lasting solutions to cavities. Placing white fillings is a very technique sensitive procedure which, if done incorrectly, can show signs of failure after just a few months. In other words, if a white filling is not placed with a high level of skill, you might find yourself needing to replace it five times in the time you would have replaced one metal filling. Finally, why should you or your insurance bear the expense of this procedure if there is no clinical reason for it? This would be like paying to upgrade your computer’s software only to get a new version with a nicer interface but which is not necessarily better and could even be worse than the older version!

As I see it, there are only a few reasons to replace metal fillings. One might be for cosmetic reasons, as white fillings look more natural than the metal ones. Although I discourage patients from replacing their metal fillings for this reason and I always discuss the risks of doing so, it is a matter of personal choice. Also, some patients are concerned with mercury vapor and mercury products emanating from their metal fillings. This is a very contentious issue among dentists and the public. Some dentists believe mercury fillings are bad and others think they are perfectly safe. Some in the public have claimed that moments after they had their metal fillings removed, they were cured of chronic illnesses like asthma and multiple sclerosis. I always find those claims peculiar because what is known is there is an elevated concentration of mercury vapor emanating from metal fillings during the process of removing them. Most people have elevated mercury levels in their blood after having these fillings removed. So if one were cured of multiple sclerosis moments after having their metal fillings removed, then perhaps mercury vapor should be studied as a cure! Or perhaps what is much more likely is that there is a strong psychological component to the process and this cannot be underestimated.

In all fairness, we need to give the other side of the coin a fair shake. Although the position of the American Dental Association is that mercury fillings are safe, it is impossible to prove such a statement. After all, it is not possible to prove a negative. Mercury is a known toxin and it would be prudent to minimize exposure to it. As such, I have chosen not use mercury based filling materials in my office. But this is a far cry from actually recommending someone replace their metal fillings because of the mercury issue. In fact, the American Dental Association has taken the position that any dentist who does this is behaving unethically.

I believe in a more level-headed and logical approach: If there are sound reasons to replace a filling (it is cracked, there is new decay around it, etc), then replacing said filling with a non-mercury alternative minimizes exposure to any mercury. That seems to be a good compromise by my standards. But this is only reasonable if the white filling replacing it is done using the best techniques and with the utmost care (see discussion on proper technique in the introduction of this site).

Oct 182014

Short answer: No, in most cases.

Long answer: Unlike metal fillings (the conventional kind also called mercury or amalgam fillings), white composite fillings are very technique sensitive. In order to be done properly, a white filling requires several steps that have to be done in the right order and with the correct timing. In between those steps, if the tooth is dried out too much, or one of the chemicals stays too long on the tooth, the result could be a very sensitive tooth long after the procedure is completed.

As always, there are exceptional cases and circumstances. Sometimes teeth with very deep cavities can be persistently sensitive for a few days or even a week or two, but this is not a rule and would still be uncommon. Also, some people are so exquisitely sensitive that they perceive pain even from the slightest stimulation. It is conceivable that these people experience pain more intensely and of longer duration after routine dental work than the average person.

If you’ve had several fillings done and they are painful for weeks or months afterward, this is not a typical response. I would encourage you to discuss the situation with your dentist or to seek a second opinion.