Posts for tag: fillings
Dental amalgam—also known as “silver fillings”—has been used for nearly a hundred years to treat cavities. There are several reasons why this mixture of metals has been the go-to material among dentists: Malleable when first applied, dental amalgam sets up into a durable dental filling that can take years of biting forces. What’s more, it’s stable and compatible with living tissue.
But there’s been growing concern in recent years about the safety of dental amalgam, with even some wondering if they should have existing fillings replaced. The reason: liquid mercury.
Mercury makes up a good portion of dental amalgam’s base mixture, to which other metals like silver, tin or copper are added to it in powder form. This forms a putty that can be easily worked into a prepared cavity. And despite the heightened awareness of the metal’s toxicity to humans, it’s still used in dental amalgam.
The reason why is that there are various forms of mercury and not all are toxic. The form making headlines is known as methylmercury, a compound created when mercury from the environment fuses with organic molecules. The compound builds up in the living tissues of animals, particularly large ocean fish, which have accumulated high concentrations passed up through their food chain.
That’s not what’s used in dental amalgam. Dentists instead use a non-toxic, elemental form of mercury that when set up becomes locked within the amalgam and cannot leach out. Based on various studies, treating cavities with it poses no health risks to humans.
This also means there’s no medical reason for having an existing silver fillings removed. Doing so, though, could cause more harm than good because it could further weaken the remaining tooth structure.
The most viable reason for not getting a dental amalgam filling is cosmetic: The metallic appearance of amalgam could detract from your smile. There are newer, more life-like filling options available. Your dentist, though, may still recommend dental amalgam for its strength and compatibility, especially for back teeth. It’s entirely safe to accept this recommendation.
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.”