February 25, 2014 | Wiley Green, DDS
What is Materials Reactivity?
In modern society we come in contact with many substances every day. They exist in every facet of our lives, including the foods we eat, the products we use and the treatments we receive. Because each of us possesses a unique biochemistry, these substances affect each of us differently and in varying degrees. For some, the effects of certain substances (and their corrosion byproducts) can be toxic and even hazardous. A substance which causes little or no reaction in one individual can prove harmful in another.
Because biochemical effects vary in each of us, it is vital that these factors be considered when choosing dental and other materials for use in the body. This is especially true with patients having special or unique health concerns.
Clifford Materials Reactivity Testing provides dentists with extensive information about their patient’s individual sensitivities. The Doctor can then
select the least offensive materials for use in individual treatment planning.http://ccrlab.com/
Crown and Bridge Materials
Used when maximum strength is desired and appearance is not a factor. There are many formulations of gold, varying from 1% to 99%.
Used when maximum strength is desired, appearance is not a factor, and a gold alloy is not biocompatible. There are different purities of titanium, with grade 1 being the purest. This is the metal used in joint replacement, dental implants, and bone pins. Cost is the same as for a gold alloy.
Used when maximum strength is desired, appearance is not a factor, but cost is most important. Since it does not contain any gold, cost is less. There are 2 basic formulations, one that contains nickel and one that is nickel-free. The controversial issue is that nickel, beryllium, cobalt, chromium, and palladium may relate to immune problems and/or toxicity.
Used when appearance and wear resistance is the most important factor. It is much more fragile than metal and may break easily. Porcelain, alone, is not normally recommended for bridges.
Used when appearance is an important factor, but when the risk of porcelain fractures and wearing down the other teeth is to be avoided. Not quite as wear resistant or esthetic as porcelain, but very acceptable for normal situations.
Combination of metal beneath either porcelain or composite
Used when both strength and cosmetics are important.
Many thanks to Ron King, DDS, Minneapolis, MN
Dental Materials Analysis:
General Facts, Advantages, Disadvantages
Composite fillings may be less durable than amalgam if the filling is large, but comparable in durability if the filling is small to average size. Composite fillings in back teeth are significantly more difficult and time-consuming to place than amalgam fillings, therefore more expensive. However, they are more natural-looking, require less tooth reduction to place, and are bonded in place for a better seal and added strength.
Composites are not totally compatible either. Most are made of the petrochemical bis-phenol, which some research indicates leeches out estrogen-like substances. Most of this problem is due to incompletely cured filling material. We use a plasma arc curing light.
Some composites are less biocompatible than others because of the amount of iron oxide, aluminum oxide, barium, and other unique materials in them. I keep 5 different kinds of material in stock to match your unique biochemical identity.
Amalgam fillings can cause hairline cracks in the tooth from temperature expansion and ‘flow’ (hammer on a nail and see how it changes shape, flattening and flowing), whereas composites do not, they flex.
Porcelain is more natural-looking than composites, but because it is harder and more brittle, it causes a wearing away of everything it comes into contact with and can crack instead of flex from high stress.
All porcelains contain aluminum oxide. The one exception is unshaded Dicor, which is weaker and not very natural-looking (over a period of 3-4 months, unshaded dicor will pick up the shade of the tooth under it; note: Dicor is off the market - most fractured in a few years. If metal is not used in a crown or bridge, it is significantly weaker and has an increased risk of breakage during normal function.
Zirconium crowns look like porcelain but are make entirely of zirconium oxide, no aluminum, no metal. Brand names are Bruxzar, Emax, Lava.
Gold fillings, porcelain fillings, indirect composite fillings, and crowns require more tooth structure to be trimmed away than for direct composites, and take 2 appointments rather than 1.
Most “gold” crowns placed today contain from 1% – 40% gold and have nickel in them which is inappropriate for those with a compromised immune system. I use only 'high noble' gold crowns which obviously cost more due to the cost of gold.
Studies of gallium alloys have reported problems with corrosion, durability, tooth fracture, and tooth sensitivity. More research and development is needed, but for now, it has been withdrawn from the market.
Some experts consider all metals, even non-allergenic or non-toxic metals, to be disruptive and therefore should never be used in the body. Since nearly all composites and porcelains contain iron and aluminum oxides, some experts limit their choice of materials to only a few. Still other experts think the use of high quality metals like high content gold or titanium is acceptable, but
only if one brand and formulation is used for the entire mouth. One must always weigh biocompatibility against function and durability.
Because of contractual language and statistics, use of titanium, high content gold, and composite for crowns, bridges, or fillings will probably result in lessened insurance benefits, even though the time, cost, and effort in doing them is the same or more as for standard gold alloy and porcelain materials.
We do not use amalgam (mercury), non-precious metals (nickel, cobalt, chromium, beryllium), or galloy in his practice.
Usually made from acrylic, stainless steel, and chromium-cobalt, but can be made nylon, gold alloy, and titanium.
Most older pink-colored acrylics and vinyls contain cadmium, which is considered toxic and/or immune reactive. The alternative is to use newer cadmium-free pink or clear materials. Cadmium was used for color stabilization, so cadmium-free materials may lose some of its color over time.
Metals are used to increase rigidity and increase retention of the prosthesis in the mouth during function. If metals are not used, the opposite is true, which is not desirable from a functional criteria.
Dr. Green has not placed a Mercury/Silver filling since 1993. Thanks to modern technology there is a healthy, more natural looking, and more biocompatible alternative than Mercury/Silver fillings that has been shown to be superior in many ways, such as:
The tooth colored material we use within our office is designed to match natural tooth structure exactly. This process makes it nearly impossible for anyone to tell you actually have had a filling placed, except for your dentist.
Tooth colored restorations are stronger than old Mercury/Silver ones because they are bonded directly to your tooth structure. This bonding process reinforces the tooth structure making it more resilient. Mercury/Silver fillings are held in mechanically. This means that the area visible to you is much smaller than the area found beneath the surface of the tooth. The old process also required the unnecessary removal of healthy tooth structure, thereby in many instances making the tooth more susceptible to breakage and damage in the future.
No Mercury or Silver
No mercury or silver, for many of our patients this is one of the major reasons they come to our office. We offer a safe, biocompatible option for their restorations that does not require the use of mercury or silver. We do no amalgam/silver fillings here.
This was the most commonly used material for back teeth. It contains 50+% mercury, and varying amounts of silver (30%), tin, zinc, and copper. It is the least costly and least time consuming to perform. It does not hold its shape over time, corrodes easily, and is expected to last 5-10 years, although I have seen it last significantly longer. The problem is that it contains mercury, a known neurotoxin (poison to the nervous system).
A special plastic material that bonds to tooth structure, is tooth colored, is more easily repairable, and requires less tooth structure to be trimmed away than any other material. It is expected to last 5-7 years, although moderate size fillings have lasted over 20 years on my patients. Research has shown that it reinforces the tooth and makes it stronger, reducing the necessity for crowning teeth with fractures. Cost and time to perform is more than old amalgam fillings. Caution: Composites are a petrochemical derivative and, as such, are a possible problem for the environmentally sensitive patient.
Indirect Composite Inlay/Onlay
Used when ideal anatomy, fit, and durability is desired, which is seldom achieved with a direct composite filling. Cost is approximately 3 times that of a composite filling and takes 2 visits.
Used when cosmetics and wear resistance is most important. It costs about the same as an indirect composite inlay/onlay and takes 2 visits. The controversy is that it contains aluminum. However, if the half-life for dissolution/corrosion is very long (e.g. 500 years), the content like aluminum can not make a difference.
Used when maximum strength is desired and appearance is not a factor. There are many formulations of gold, varying from 1% to 99%. It costs approximately 3-4 times more than a composite filling and takes 2 visits.
Used when a gold alloy is not biocompatible, otherwise the benefits, cost, and time to perform are the same about as for a gold alloy, even though it is not a precious metal. It takes 2 visits.