Posts for tag: fillings
Over the last century and a half millions of people have had a tooth cavity filled with “silver” amalgam. Perhaps you’re one of them. The use of this effective and durable filling has declined in recent years, but only because of the development of more attractive tooth-colored materials.
At the same time there’s another issue that’s been brewing in recent years about this otherwise dependable metal alloy: the inclusion of mercury in amalgam, about half of its starting mixture. Various studies have shown mercury exposure can have a cumulative toxic effect on humans. As a result, you may already be heeding warnings to limit certain seafood in your diet.
So, should you be equally concerned about amalgam fillings — even going so far as to have any existing ones removed?
Before taking such a drastic step, let’s look at the facts. To begin with, not all forms of mercury are equally toxic. The form causing the most concern is called methylmercury, a compound formed when mercury released in the environment combines with organic molecules. This is the form certain large fish like salmon and tuna ingest, which we then ingest when we eat them. Methylmercury can accumulate in the body’s tissues where at high levels it can damage various organ systems.
Dental amalgam, on the other hand, uses elemental mercury. Dentists take it in liquid form and mix it with a powder of other metals like silver, tin and copper to create a pliable paste. After it’s placed in a prepared cavity, the amalgam hardens into a compound in which the mercury interlaces with the other metals and becomes “trapped.”
Although over time the filling may emit trace amounts of mercury vapor, it’s well below harmful levels. You’re more likely to encounter “un-trapped” mercury in your diet than from a dental filling. And scores of studies over amalgam’s 150-year history have produced no demonstrable ill effects due to mercury.
Although it now competes with more attractive materials, amalgam still fills (no pun intended) a necessary role. Dentists frequently use amalgam in less visible back teeth, which encounter higher chewing pressures than front teeth. So, if you already have an amalgam filling or we recommend one to you, relax — you’re really in no danger of mercury poisoning.
For over a hundred years dental amalgam — a combination of silver, mercury, tin and other metals — has been an effective filling material for teeth damaged by decay. But it has one major drawback — its metallic appearance stands out in stark contrast to the natural color of teeth.
As an alternative, composite resin fillings can match the color, shape and texture of natural teeth. These materials and the techniques used to bond them are proving just as effective as and more aesthetically pleasing than dental amalgam.
Fillings help protect and preserve a decayed tooth. By first removing decayed tooth structure through drilling, the resulting void is filled with durable material that strengthens the tooth and provides it protection from further decay.
The ultimate goal for restoration is to return the tooth to as near normal form and function as possible. Dental amalgam serves well in terms of function, providing the tooth strength in the face of the daily biting forces it encounters. In contrast, composite resins excel in appearance, but haven’t always matched the durability of amalgam. They’re material construction has improved over time, though, as well as the techniques used to bond them to teeth.
Most of these bonding techniques incorporate layering. The first step is to seal the dentin (the porous, living tissue just below the enamel); we then build up the composite material layer by layer within the tooth using special bonding adhesive and curing lights. In some cases where a large volume of tooth structure must be replaced, the restoration is first formed on the tooth and then removed for curing before being cemented into the tooth or a separate restoration is formed by a dental lab.
The end result is a tooth which both looks and functions like a fully intact tooth. Though care must be taken not to subject composite resin restorations to undue forces (no cracking open nutshells, for example), your new filling should continue to serve you and look great for a long time to come.
If you would like more information on metal-free restorations, please contact us or schedule an appointment for a consultation. You can also learn more about this topic by reading the Dear Doctor magazine article “The Natural Beauty of Tooth Colored Fillings.”
It takes a lot of skill, experience, talent and artistry to create tooth restorations that look so natural that no one can tell them apart from the originals. To do so requires understanding of the normal anatomy of a tooth as well as of the interactions of light and color.
How the anatomy of a tooth determines color
The color that we perceive when looking at a tooth results from the combined appearance of the tooth’s center core (dentin layer) and its covering enamel. Going from the outside in, the enamel is made of tightly packed crystals of calcium, which cause it to be one of the hardest substances naturally produced by animals. The crystals are also responsible for a tooth’s brilliance and translucence. The dentin is more like bone, a porous living tissue composed of microscopic tubes, interspersed with more calcium crystals. In the very center of the tooth is a central chamber containing the pulp and nerves.
Each of these layers has its own physical and optical properties. Since the enamel is translucent and the dentin is more opaque, most of the tooth’s color comes from the dentin and is transmitted through the enamel layer. Factors that affect this transmission include the thickness and age of the enamel as well as external tooth whitening.
If the enamel is more translucent, more of the color of the dentin shows through. If it is more opaque, the enamel absorbs and reflects light so that less color is visible and the enamel looks brighter.
The language of color composition and reflected light
Color means the whole spectrum in the rainbow. The spectrum is made up of the three primary colors — red, blue, and green. When all are combined, they create white light.
Hue refers to the brightest forms of the colors. The color we perceive depends on the dominant wavelength of light that is reflected by an object.
Value refers to a color’s lightness or darkness. A brighter color has a higher value.
Chroma is the amount of identifiable hue in a color. An achromatic color (without hue) appears gray.
Saturation is a measure of a color’s intensity.
This terminology of color is used not only by dentists and dental technicians, but also by a wide range of artists. It implies expertise and understanding of how colors work, how they vary and change and affect one another.
Contact us today to schedule an appointment or to discuss your questions about bonding to repair chipped teeth. You can also learn more by reading the Dear Doctor article, “Artistic Repair of Front Teeth with Composite Resin.”
Are tooth-colored fillings safer than silver fillings?
No. Both are considered safe based on the most reliable and up-to-date scientific evidence. Still, tooth-colored fillings do have some definite advantages. Not only do they blend in with your smile far better than “silver” (dental amalgam) fillings, but they often require less removal of healthy tooth structure. That’s because in order to fill a tooth with amalgam, it is necessary to create indentations in the tooth called “undercuts” to hold the amalgam in; this requires the removal of some healthy tooth material. With a tooth-colored filling, we need only remove the decayed part of the tooth to place the filling.
Are there any disadvantages?
Yes, tooth-colored fillings don’t always wear as well as metal fillings — particularly on back molars where they are subjected to the most stress from chewing. They are also more expensive and less likely to be fully reimbursed under dental insurance plans.
Are there different types of tooth-colored fillings?
Yes, three different choices of tooth-colored fillings are available:
- Composite — This mixture of plastic and glass is the most common type of tooth-colored filling. Newer materials can hold up almost as long as amalgam fillings and look very natural, though they can stain over time just as natural teeth do.
- Porcelain — High-tech dental ceramics are considered the most aesthetic choice of filling material. They don’t stain as composites can, but their relatively high glass content can make them more brittle and prone to breakage. They may be more expensive than composites.
- Glass Ionomer — Made of acrylic and glass powders, these inexpensive, translucent fillings blend in acceptably well with natural teeth and have the advantage of releasing small amounts of fluoride to help prevent decay. However, they generally don’t last as long as other restorative materials.
We would be happy to offer guidance on which choice would be best in your own unique situation.
If you have any questions about tooth-colored fillings, please contact us or schedule an appointment for a consultation. You can learn more by reading the Dear Doctor magazine article “The Natural Beauty of Tooth-Colored Fillings.”