Mercury Free Dentistry
More Than “Just a Filling”
Silver-Mercury Fillings, Nanoparticles and White Fillings
People ask or wonder if we still place silver-mercury fillings in our patient’s mouths. The answer is no, we haven’t for over 25 years and we won’t in the future because it is mid 1800’s technology, their corrosion, creep and expansion are not great physical properties for the long term health of the tooth, and in my mind they are not an acceptable cosmetic choice. My opinion is the best cosmetic choice is tooth colored and that is what we use. Today, we rarely even place gold restorations.
Our experiences shape us and I had an experience more than 25 years ago where I placed a large silver-mercury filling in a beautiful young woman - her first cavity. It was a gorgeous, shiny, perfectly fabricated filling, but when I looked at it, as she cordially said thank you and goodbye, I had a sickening feeling in my gut. For the first time, I just realized that I had put a black scar in her mouth. It was as if she had gone from Cinderella to Cruella Deville… and under my supervision! I could not get it out of my head, and if I couldn’t get over it, what was she going through? I was afraid to ask, never did ask, vowed to never do it again, and by the way, never saw her again. Don’t get me wrong, I don’t think less of you if you have silver-mercury fillings, but I would think less of me if I ever put another one in.
Let’s face it, not many people like to go to the dentist even though it should be a painless experience. Job satisfaction for a dentist comes from our personal integrity in knowing everything possible was done, and to be able to step back and pat myself on the back for how great it looks and what an excellent job I just did. For my patients, the experience should be pleasant, painless and have incredible value for their investment.
Nanoparticles – A New Reason
Research in nanoparticles could be a new emerging scientific basis for not placing silver-mercury fillings. This may be a little technical so bear with me. A nanoparticle is about 500 times smaller than a human hair or 100nm and under. The smaller a nanoparticle is, the more it can influence your biochemistry. Nanoparticles of metal can exert a biochemical effect that is different than the same element’s ionic form (dissolved in water). Nanoparticles do not accumulate in the blood but in the cells and organs. We do not yet know the far reaching effects of nanoparticles because different nanoparticles (atoms or molecules) affect different cell types differently. This is biochemically revolutionary! We are talking about inert, not biochemically active, substances becoming biochemically active when the particle size is small enough.
How this science relates to dentistry is that I have seen people wear holes in metal crowns. I have also seen silver-mercury fillings worn as flat and shiny as glass and no one had ever felt a particle of dust. Therefore, it seems reasonable to me, as you wear down your teeth and dental restorations, you are creating nanoparticles. [So far, I have not been able to find any articles on the resultant particle size generated from dental material attrition. If you find one, please forward it.] If every dental restoration is a nanoparticle generator then the material the restoration is made of becomes important.
I am hopeful this emerging scientific knowledge of nanoparticles will shed new light on the silver-mercury filling controversy and eventually unite the dental community. Here is a reference for a review article by Helinor J. Johnston published in the Critical Review of Toxicology April 2010, that says silver nanoparticles are inflammatory, oxidative, genotoxic and cytotoxic. (Reference: Crit Rev Toxicol. 2010 Apr;40(4):328-46.) If you want to research it for yourself, just go to Pubmed and search “silver nanoparticle toxicity”, you will find plenty to read. So in summary, even if the heavy metal mercury in the silver-mercury filling is of no biochemical consequence, current research in nanoparticles implies that the silver in the silver-mercury filling material should now be in question. Remember this thinking is not yet 100% dentally accepted, but when a new scientific principle is discovered, part of my job is to apply that principle to your dental health and error should always be on the side of caution.
Bioethics
That being said, bioethically, I will only recommend replacement of silver-mercury fillings if there is decay, leakage around or underneath the filling, there is a crack in the natural tooth structure that could jeopardize the tooth or if it is a cosmetic compromise. If your free will of choice is involved, provided you still have a choice in America, we will serve your requests as long as it leads to a technological or esthetic upgrade.
White Fillings and Slow Speed Drilling
In placing a white composite or ceramic restoration, the tooth is not an inanimate rock; it is a living breathing organ and should be treated like the natural gemstone it is. Most dentists see how fast they can drill a tooth with a cavity because what patient wants to sit in the dental chair longer than they have to? The problem is, the speed at which a tooth is drilled and how it is drilled makes a difference. One model suggests that too much speed causes a special vibration that can start micro-cracks in the crystalline structure of the tooth. Another model relates to the fact that the live tooth is made of little crystalline tubes that each have a cellular (pulpal or nerve) extension toward the enamel. If the tooth is drilled too fast, those extensions are pulled from the tooth from the rotational cutting and when finally separated, suck back into the tooth tubes pulling debris and bacteria with them. As a kid, have you ever pulled on a worm partially exposed, it breaks and the other half disappears into the ground? Whether these models are correct or not, does not matter. What matters is that my patient’s teeth have much less post filling sensitivity since I have been adhering to the principles of low speed drilling, and that is great for everyone.
Cavity Indicator and Rubber Dam
We routinely use special cavity indicating dyes that stain any remaining decay or compromised tooth structure. In addition to the experience of feel, it’s comforting to have a visual confirmation that all decay is gone. The use of a rubber dam as a barrier is the rule, rather than the exception, as you need to understand that moisture control is of paramount importance for any bonding procedure be it spit, blood or water. It’s pointless to go through every successive step in restoring a tooth, if you compromise any one step that could lead to a restoration failure and possibly a root canal or extraction. Moisture contamination in the tooth is one of the main reasons dentists are still placing 1800’s technology silver mercury fillings.
Laser Bacteria Reduction
Another item that further reduces sensitivity but increases time, has a small additional cost attached, is not covered by insurance, and of course is optional, is Laser Bacterial Reduction or LBR. A laser is used with just enough energy to disinfect the internal surfaces of the tooth just prior to bonding. Think of it as an “electrocution” with photons instead of electrons, a deathly sunburn that is a 99.9% sterilization and therefore is termed disinfection. I used to think if there were any remaining bacteria under a filling, they would be inactivated from being given a “cement overcoat” from bonding, but since the addition of LBR we have found our post filling sensitivity rates to drop again further. Now our post filling sensitivity rates are just a fraction of what they were prior to these new procedures.
More Than “Just a Filling”
I hope you better understand that a filling is more than just a filling. I could go on and on about bonding agents, their bond strengths, film thickness, toxicology of polymer chemistry, the fillers in each brand of composite, compressive strengths, material wear rates etc. but the point is, all these little things go into what I want in my own tooth and that is exactly what I will do for you. I also know that in the end what matters is, can you comfortably chew on the tooth, does food get stuck around it and does it look like a virgin tooth? I have found that the only way to produce those requirements day after day is by using the best of the best in materials and taking the necessary time to complete all the steps without compromise. I know I deserve it, why shouldn’t you?
Looking forward to seeing you soon.
Gary B. Wiele DDS