Lead in Dental Crowns
Seven things you should know about lead and dental porcelain ceramic crowns.
There has been a recent spike in the news media concerning the amount of lead that has been found in dental crowns, especially those dental crowns that are fabricated overseas. The reason that is of concern is that the dentist that is placing the crown on people often has no knowledge of where the crown was made or of the exact chemical composition of that crown.
I have had a lot of customer concerns lately over this matter, and have decided that my first true blog entry should discuss this matter. I am entering into this topic with an entirely open mind. Of course, I have extensive
experience with dental crowns and their intricacies and nuance, but I wanted to discover for myself whether this was a legitimate health concern or not. This blog will attempt to address the questions of whether lead in dental crowns is truly a concern, how much lead is safe, methodology for testing dental crowns, and what you as a consumer can do to reduce your risk from lead poisoning from dental crowns. I enter this discussion with an open mind, and encourage you to do the same. At the risk of dental blasphemy, I have condensed this dental information down into bite sized chunks that can easily be digested. So here is some food for thought. Enjoy.
1. All (and I mean ALL) dental porcelain has measurable amounts of lead. Reputable manufacturers of dental porcelain go to great lengths to reduce this amount, but the fact of the matter remains that porcelain is basically glass, and glass is made from melted sand, and sand is made from silicon dioxide, which is basically dirt. Trace amounts of lead can be found in dirt, silicon dioxide, sand, glass, and dental porcelain. If the measuring instrument is sensitive enough, it is detectable.
2. Different countries have differing standards of what constitutes an acceptably safe level of lead, and what constitutes a dangerous level of lead. These numbers are arbitrary. We’ll get to that in a second.
3. Is it dangerous? Not really, because dental porcelain and glass are fairly insoluble in water. The lead is encapsulated and encased and entrapped in the porcelain, so as long as the porcelain doesn’t dissolve in your saliva, then these trace amounts of lead should be relatively harmless. Dental ceramic porcelain that fractures off and is swallowed and is subject to stomach acid is another story; however, even stomach acid doesn’t really do a very good job of dissolving glass. Hydorfluoric acid is much more effective (but I digress). Still, do you want this in your body?
4. So what is a safe level of lead in your dental crown? I would postulate that it is not the amount of lead in the dental crown, but the amount of lead that leaches off of the dental crown into your body that is the area of concern. The lead in the dental crown is safely encapsulated or trapped. The amount that is leaching into your body is the amount that you should worry about. To me, the USA just makes an arbitrary number that is higher than Holland and half that of China and calls it a safe level. That way, it appears that they have done some research and can justify a large government grant. If they were to do a true study, then they would have to subject some citizens to lead poisoning, which would be unconstitutional and illegal and immoral. The US Government would never want to be any of those things, of course, so the scientific studies remain untested.
5. If someone was to test it, what would it take? Ok, here is where it gets a little complicated. Skip this part if you want. You would need to measure the amount of attrition that your molars make each year. Worst case scenario: one millimeter every ten years. At that rate of attrition, your teeth would wear off to flat with the gumline in 50 years. Your molars that came in at age twelve would be flat and flush with your gumline at age 62. Assuming your first dental crowns were placed at age 25, and you had one placed per year from age 25 to 62 (as dental insurance companies would like you to do), then you would have received about 37 dental crowns over your lifetime. That number seems a little high, so let’s say one dental crown every other year, for a total of 16 dental crowns over a lifetime (on molars), which is more in line with what actually happens in real life. Each dental crown has approximately one millimeter of porcelain over the occlusal (or chewing) surface. This is assuming this is worn completely away before the crown fails and has to be replaced. Let’s also assume an average size of 5mm and 10mm in the side to side and front to back dimensions, respectively. So 50 cubic millimeters per dental crown is ground into a fine powder and ingested per dental crown that you have. And if you get a total of 16 dental crowns in a lifetime, this amounts to 50 x 16 = 800 cubic millimeters of ingested dental porcelain ceramic. The USA safe amount of lead is 200 parts per million as an acceptably safe level. So 800 x 200 / 1000000 = 0.16 cubic millimeters of lead ingested over a lifetime (remember, this is worst case scenario). The actual uptake into the human body would depend on the size (diameter) of the particulates and the resultant surface area available for contact. We can assume 25% contact area in the worst case and conclude that 0.16 x 0.25 = 0.04 cubic millimeters of lead will be potentially at risk for uptake into the human body over the course of a lifetime. And the question that you have to ask yourself is: is 0.04 cubic millimeters of lead too much? Compared to what? Asbestos? Mercury? Nickel? Silicone?
6. What can I do to protect myself and my family?
a. Choose a reputable dentist who uses only dental laboratories who in turn utilize only reputable ceramic materials from reputable ceramic manufacturing companies. Make sure your new dental crown is not going to be fabricated off shore. True, the USA regulatory system may have some flaws, but it’s the best that we have, and I personally would like to have some kind of regulation rather that no regulation at all.
b. Also, reduce the amount of attrition that you subject your dental crowns to. If you don’t grind them away so fast, then they don’t have to be replaced as often. Prevention is the name of the game here, so do whatever it takes to avoid clenching or grinding your teeth at night.
c. Choose all-gold crowns instead of porcelain. If it really concerns you that much, consider all-gold crowns. They are very bio-compatible and would reduce the amount of lead that you get over a lifetime. The only bad thing is the color (which is subject to debate).
7. Put it in perspective for me,
Dr. Bayne. Ok, after reviewing the math, I personally
wouldn’t be too worried about it if you are getting the good kind of
crown from a reputable USA dentist. I would be much more concerned with
mercury fillings (which, unlike dental porcelain, are subject to the corrosive properties of stomach acid) and with the nickel content that is found is cheap crowns. Nickel is not very biocompatible and should be avoided as much as lead.
Disclaimer: Yes,
Dr. Bayne holds membership in both the
Academy of General Dentistry and the
American Academy of Cosmetic Dentistryand is a practicing cosmetic and restorative dentist in Scottsdale
Paradise Valley, AZ; however, this article is not healthcare advice. This article is entirely anecdotal and is based on opinion, and meant for discussion purposes rather than educational or scientific purposes. This article has no scientific value other than to spark dialogue among those interested in the topic of discussion. Please use your best judgment when choosing your healthcare and do not take this entertainment-based article as a substitute for the information that can be provided by your healthcare provider. This is not meant as, nor is it an appropriate substitute for, healthcare advice from your licensed practitioner.
