Posts for tag: fillings
Recently, a number of new filling materials that mimic tooth color have come into popular use and, so far, have proven more durable than past versions. Even so, the traditional metal-based dental amalgam remains a viable choice, especially for less visible back teeth and their higher biting forces.
Used for more than a century, dental amalgam is a metal alloy composed of silver, mercury, tin and copper. The mixture is carefully proportioned so that potentially hazardous mercury is kept to a minimum and bonded with the other metals. Amalgam in its initial form is quite pliable so that it can be molded into the tooth structure under repair. Afterward it sets hard to form a durable filling that can withstand the daily force generated when we bite and chew food.
Besides durability, dental amalgam rarely causes an allergic reaction in a patient, and it’s easy for trained dentists to apply. On the downside, however, it can cause temporary temperature sensitivity in the tooth just after filling, and the tooth itself may require some removal of healthy structure to help keep the filling in place. And from an aesthetic point of view, its metallic appearance is considered unattractive especially for front teeth.
The presence of mercury in amalgam has also raised concerns over the years. “Free” mercury — atoms that escape through vapor emitted by the metal — can enter the bloodstream and potentially harm the nervous system. But after extensive study and research, U.S. and international health bodies including the American Dental Association have concluded any free mercury released during chewing is extremely low and well below any harmful levels. These studies have also found no ill effects in either children or adults with dental amalgam fillings.
Deciding on the type of filling material to use — dental amalgam or a newer composite resin, resin ionomer or glass ionomer — depends on a number of factors including the location of the teeth to be filled, the extent of decay and your personal preferences. Taking these into account, we’ll be happy to discuss which type of filling will suit you best for repairing decayed teeth.
If you would like more information on filling material options including dental amalgam, 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 “Silver Fillings — Safe or Unsafe?”
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.”
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.
Q: I’ve never heard these terms used in dentistry. What are they?
A: In the decorative arts, an inlay refers to a small piece of distinctive material that’s set into a larger matrix: a mother of pearl accent worked into the lid of a wooden box, for example. In dentistry, it means something similar: a filling (or restoration) that’s fabricated in a dental laboratory, and then set into a tooth in an area that has been damaged or lost.
Q: What’s the difference between inlays and onlays?
A: An inlay is made to fit in between the cusps (small points or ridges) of a back tooth (molar or premolar), and it covers only a small region of the biting surface of the tooth. If the restoration covers one or more of the cusps, it’s an onlay.
Q: Why would I need to have one of these restorations?
A: When a tooth has suffered damage (from decay or trauma, for example), and the affected area is too large to fill with a simple filling — but not large enough to need a full crown (cap) — then an inlay or onlay may be just right. Both of these procedures are considered “indirect fillings,” because the restoration itself is custom-fabricated in a laboratory and then bonded to the tooth in the dental office.
Q: What is the procedure for getting an inlay or onlay?
A: It’s similar to having a crown placed, in that it typically takes more than one office visit — yet an inlay or onlay involves less removal of tooth structure than a crown would require. On the first visit, after the area has been anesthetized (usually with a numbing shot), any decay is removed, and the tooth is shaped to receive the restoration. Next, a model of the tooth is made (either with putty or in digital form), and the tooth receives a temporary filling. The laboratory uses this model to create the actual inlay or onlay, which may take a few days; it is then permanently attached to the tooth on a second visit to the office. However, with today’s advances in CAD/CAM (computer aided design/ manufacturing) technology, some inlays or onlays can be made in the office and placed in the same visit.
Q: What else do I need to know about these tooth restorations?
A: Both inlays and onlays are strong and long-lasting restorations that need no more care than you would normally give your teeth: namely, regular brushing and flossing, and periodic checkups at our office. But because they don’t require the removal of a great deal of natural tooth material, they are considered relatively conservative treatments. After a thorough dental examination, we can recommend the type of tooth restoration that’s most appropriate in your individual circumstances.
If you’d like to find out more about inlays or onlays, please contact us or schedule an appointment for a consultation. You can also read the Dear Doctor magazine articles “Porcelain Crowns & Veneers” and “The Natural Beauty of Tooth Colored Fillings.”