Health Concerns: A Brief Overview of the Effects of Dental Amalgam on the Teeth and Body by C. Michael Willock, DDS 2008 Chapel Hill, NC

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1 Health Concerns: A Brief Overview of the Effects of Dental Amalgam on the Teeth and Body by C. Michael Willock, DDS 2008 Chapel Hill, NC There are several reasons why the use of dental amalgam may not be a good idea to be used in the mouth as a restorative material. Although dental amalgam has been used worldwide for over 150 years and has no doubt saved millions of teeth from having to be extracted, it is a material whose time has come to an end. Today, there are many dental materials that perform as good or better than dental amalgam and are a lot safer to use for the patient, doctor and staff. Safety concerns regarding this material have been reported in various dental and medical journals since the 1920 s, but have been overlooked by the established media. In this paper we will consider: Physical Properties, Toxic Properties and Electrical Properties of dental (mercury) amalgam. Physical Properties - Dental Amalgam Cracks and Splits Teeth One of the main concerns of amalgam is the physical properties of the material. Mercury amalgam cracks and splits teeth as it heats up and cools down from eating hot and cold foods. When it gets hot from eating hot foods such as a baked potato or hot pizza, it expands nearly 3 times as fast as natural tooth structure, and places great stress on a tooth acting like a wedge and cracks it (figures 1a and 1b). In extreme cases it will split the tooth down the middle (figure 2a, 2b and 2c) or split off a cusp (figure 3). Then, when it cools down or is chilled, as when one drinks a cold drink such as ice tea or eats ice cream, it contracts faster than the natural tooth structure and a small gap opens up at the margins of the restoration. Leakage occurs and bacteria enter between the tooth and the restoration. When the tooth warms back up to body temperature, the gap closes and seals in whatever happened to be in the patient s mouth and saliva at the time. Dental amalgam does not bond to a tooth like the newer materials, and therefore does not seal the tooth. Because it does not seal the tooth, it leaks from the day it is placed. Eventually, the amalgam corrodes and this black corrosion (silver sulfide) is what is commonly found on the inside of a tooth when the old amalgam is removed. 1

2 Figure 1a Note cracking on side of tooth. The larger the mass of metal, the more extensive the cracking and splitting. Figure 1b Cracking on two sides of the tooth. It would not take too much stress in the wrong direction, to completely split off this cusp in the upper left of the photo. Figure 2a Stress from the amalgam has split the tooth from front to back. 2

3 Figure 2b Stress from amalgam has split the tooth right across the top of the pulp chamber. This is what the tooth looks like after the amalgam has been removed, and before restoration. Figure 2c here. Tooth split down the middle due to old amalgam stress. Extraction is required Figure 3 Upper right cusp next to patients tongue is totally split away from tooth and is literally flapping in the wind. Note recurrent decay (black areas) on left side of amalgam margin from leakage. 3

4 Dental amalgam is basically a mix of mercury and silver, with various amounts of tin, copper, and zinc added into the mix. The different formulas give it different properties. These fillings are often called silver fillings because of the silver appearance when newly placed. After awhile they turn black due to corrosion. Mercury (Hg+) and Silver (Ag+) are both positive ions, and therefore repel each other with great force when mixed. If you have ever tried to push together two positive or two negative ends of a magnet, you know that it can t be done because of their strong repelling forces. So it is with mercury and silver. It is like trying to mix oil and water. They are always repelling each other. Because of this, the amalgam actually swells over time and expands out of the tooth preparation. This characteristic, in addition to the thermal expansion and contraction discussed above, is devastating to the strength of a tooth. (Note figure 4a mild expansion, figure 4b moderate expansion and figure 4c severe expansion.) Figure 4a Damage from mild expansion. Note beginning of decay between the amalgam and tooth structure, and the chipping of the brittle amalgam, just above the gumline. Figure 4b Damage from moderate expansion. Note decay (white area) in tooth next to the amalgam on the upper right cusp next to the amalgam. 4

5 Figure 4c Damage from severe expansion and decay. Physical Properties - Leakage and Decay When mercury amalgam is first placed, it is packed into the cavity preparation while the amalgam is in a flexible plastic form, and after a couple of hours, turns very hard. Although it is very hard, it does not add much strength to the tooth, because it does not bond to the tooth, and it begins to leak very shortly afterward due to thermal expansion and contraction. Because it is not bonded to the tooth, it does not seal it. In essence it is just a tight press fit. Because the mercury restoration is not sealed, the mercury amalgam begins to corrode after awhile, and it is this corrosion or rust that ultimately makes something resembling a partial seal between the tooth and the mercury restoration. When a mercury restoration is placed in a tooth, it rests on the floor of the cavity preparation which is a layer of the tooth called dentin. This is the second layer of the tooth and is just below the outside layer of enamel. The outer enamel is a solid hard crystalline material, and the dentin is a very porous material somewhat like a sponge. As leakage and corrosion occur, saliva containing bacteria, food particles, and sugar, reach the porous dentin layer and soak in. As the bacteria start to work, and decay begins in the porous layer, it soon turns the dentin to mush, and the acidic infection eats its way into the nerve chamber (the heart of the tooth) and kills it. Although the tooth may seem OK when looking at it, there is usually a lot of decay found under the amalgam when it is removed (figure 5a, 5b, 5c, 5d). Some teeth have severe leakage (5e). 5

6 Figure 5a Some teeth may seem OK at first glance, but recurrent decay due to leakage is usually found beneath, after the amalgam is removed. Figure 5b Decay found after amalgam removal, and before cleaning out the tooth for a new restoration. Note how the decay is working its way into the porous dentin. Figure 5c Patient presented with broken lingual cusp on upper molar due to amalgam fracturing. 6

7 Figure 5d Damage and decay visible after amalgam removed, but before decay removed and restoration. Note how decay and corrosion have penetrated deep into tooth structure. Figure 5e Severe leakage and decay. Toxic Properties - Toxic Effects of Mercury Amalgam Toxic reasons for not using dental amalgam include the following: Dental amalgam contains mercury, which is the second most toxic element on the planet after Plutonium. Both the EPA and FDA consider it a dangerous material, and a dentist must take special precautions to both store it and use it. If it is spilled on the floor during mixing, or in process of placing it in the patients mouth, it is considered a serious environmental hazard, and special procedures must be followed to clean it up. Once it is placed in the patient s mouth however, it is considered safe by dental boards. (Does this make sense?) 7

8 Dental amalgam also off-gases continually as we chew, and this vapor is inhaled and absorbed by the body (figure 6a). It passes into the blood stream, and attaches to the hemoglobin molecule that carries oxygen around the body, and various other bodily cells and tissues. Each hemoglobin molecule has binding sites for four oxygen atoms, and Mercury can knock off, and replace one or more of the oxygen atoms on the hemoglobin binding sites. This results in lower oxygen saturation in the blood stream, and may contribute to chronic fatigue, brain fog, and because the mercury is transported all over the body by the blood, it may settle in many different organs, causing a variety of diseases, including various autoimmune diseases. Many people are already carrying a toxic burden in their tissues from environmental pollutants, and may have a genetic predisposition or susceptibility to any further toxins. This may push them over the edge, and result in an autoimmune or other disease. Figure 6a Mercury vapor off gassing from an extracted molar after being rubbed with a pencil eraser (similar to chewing food or gum). For further information, see the website of the International Academy of Oral Medicine and Toxicology at and view the short video on the Smoking Tooth = Poison Gas. See also the Scientific Case Against Mercury Amalgam at m.pdf Mercury in the body takes 3 forms and has varying degrees of toxicity: Mercury Vapor Hg No bad effects unless in the ionic form, but in the body it ionizes very easily. Crosses the blood brain barrier very easily and then transforms to the ionic form which causes problems, and is a lot more difficult to remove from the brain. Ionic Mercury Hg++ Vicious to adjacent cells Neuro-toxic Attacks the optic nerve 8

9 Nasal sinus to the brain stem Crosses Blood Brain Barrier and interacts with -SH bonds in various molecules Targets mitochondria (cellular powerhouse) Binds to hemoglobin (mentioned above) Methyl Mercury - CH3-Hg+ Highly lipid (fat) soluble 45 times more soluble than Hg+ Causes DNA damage Can be a cause of birth defects Can cause endocrine disturbances Figure 6b See How Mercury causes neural (brain) degeneration at Also found at in the video library. All dental materials must have a Material Safety Data Sheet prepared by the manufacturer of a product. In the U.S., the Occupational Safety and Health Administration requires the MSDS be available to employees, for potentially harmful substances handled in the workplace. A Material Safety Data Sheet (MSDS) is designed to provide both workers, and emergency personnel, with the proper procedures for handling or working with a particular substance. This includes information such as, physical data (melting point, boiling point, flash point etc.), toxicity, health effects, first aid, reactivity, storage, disposal, protective equipment, and spill/leak procedures. The MSDS sheets for the various brands of dental amalgam used in dentistry, list it as toxic. It is so toxic, it can damage many nerve fibers in the body (but they don t tell you this). See Figure 6b. Further toxicity can be observed as amalgam tattoos. Mercury leaching from amalgam fillings can move into soft tissue in various places in the mouth, and concentrate into small bluish-black spots several millimeters to a centimeter across. These sometimes have black soft pathological bone underneath. This mercury contamination in the soft tissue is permanent, and does not go away with time.(figure 7a, 7b, 7c). 9

10 Figure 7a Upper left maxillary ridge Figure 7b Right anterior of edentulous patient. Figure 7c Left anterior of same edentulous patient 10

11 Electrical Properties Galvanic effects of dental amalgam Natural teeth do not have an electrical charge. Teeth with metal in them do. The electrical current can be measured in milliamps, and different teeth with different metals in them, can have great variations in electrical charges. A battery consists of two dissimilar metals, with an acid in between (like your car battery). When there are two or more different metals in the mouth, and saliva in between, there are electrical currents flowing in the mouth, just like a battery. This is called a galvanic reaction and is commonly felt when one has experienced a small piece of aluminum foil from a baked potato that touches a tooth with an amalgam in it. The sharp electrical jolt one feels is actually a strong electrical current that the nerve of the tooth is feeling, and there are instruments that can measure this current. Furthermore, some people are very sensitive to this current, and it can cause problems for them. This has been a very brief overview, highlighting some of the problems encountered with dental amalgam. It should be known, that if one has certain health problems they or their physician feel are related to the presence of dental amalgam, there are special procedures employed to minimize risk, when it is removed and replaced with safer non toxic materials. Very specific safety procedures must be followed to protect both the patient, doctor and assistant. The amalgam is not simply drilled out. Improper removal can cause more harm than good. If you have any questions, we will be happy to spend time discussing them with you. 11