Posts for: March, 2013
A “crown” or a “cap” is the term used to restore a decayed or broken tooth that needs to be completely encased to protect the tooth beneath it. A crown's dual purpose is to restore the tooth's form and function. Decades ago gold was the material of choice for a crown. What we ultimately choose depends on a particular crown's requirements with regard to the tooth's appearance and function, and to some extent what you want.
Gold: Gold crowns last the longest and wear the best (at about the same rate as natural teeth), but they are not used as frequently today, especially if they are visible in a person's smile. Gold crowns are made of cast gold, a technique that has been in use for over a hundred years. They can last for decades, and have been known to last 50 years or more. They tend to cost less per tooth than porcelain or other materials.
All-Porcelain: “All porcelain” crowns have a natural appearance and as technology improves they are gaining popularity. Dental porcelains are composed of ceramic substances that are variations of glass. This gives them their translucent, lifelike appearance — but it makes them brittle and subject to fracture. Therefore all-porcelain crowns may not be a good choice for back teeth because they frequently fail under the biting forces applied during chewing and especially adverse habits like tooth clenching or grinding. Porcelain crowns are made of material that doesn't wear. Consequently, it can cause excessive wear to the teeth they bite against.
Porcelain-Fused-to-Metal (PFM): PFM crowns have been in use for more than 40 years. They combine a substructure of gold or platinum for strength and have porcelain “facings” for the visible surfaces. In some ways they combine the best of both worlds, but they do have some problems; the metal can show through the porcelain, detracting from its life-like appearance. These crowns can have a functional lifespan of about 20 years or more.
New and Future Materials: Newer “pressed-ceramic” restorations and computer-milled ceramics have received good reviews for aesthetics and service. These new materials are being intensively researched. Initial results look good, but we'll have to see how they last over time.
Contact us today to schedule an appointment or to discuss your questions about crowns and other dental restorations. You can also learn more by reading the Dear Doctor magazine article “Gold or Porcelain Crowns?”
Do you have silver dental fillings that you wish you didn't have? Wouldn't it be nice if no one could look in your mouth and see how many cavities you had as a kid? Tooth-colored fillings may offer a solution to the problem of too much metal in your mouth. How much do you really know about non-metallic tooth-colored fillings? Take our quiz and find out.
True or false: Tooth-colored fillings are a radical new technology.
False. A variety of dental porcelains and composite resins have been successfully used in tooth restoration for many years. These materials have been designed to mimic the properties of the two major components of teeth: the hard outer enamel, and the bone-like inner dentin. Our increasing understanding of tooth structure and composition has led to better and more natural-looking filling substances.
True or false: Teeth must remain rigid under the pressure of the bite.
False. At one time, metal amalgam (silver) fillings were preferred because of their extreme hardness. But we now know that the crowns of our teeth actually flex under the forces of the bite. This discovery has spurred the development of new methods and materials to stabilize the restored tooth and reduce the incidence of premature failure.
True or false: It's usually more complicated to put in a tooth-colored filling than a metal one.
False. Regardless of which material is used, the basic process of filling a tooth is the same. The dentist prepares the tooth for treatment, removes decay, and places a filling directly into the tooth. If the filling is moderately deep, a tooth-colored filling may be set in several layers which are successively “cured” or hardened. More extensive restorations may require more than one visit, but the natural-looking results generally justify the extra time.
True or false: Regular metal fillings make the tooth structure stronger.
False. Properly securing an amalgam filling may require the tooth to be “undercut,” meaning that a greater amount of healthy tooth material must be removed. This can weaken the tooth structure, eventually leading it to chip and crack. Non-metallic fillings don't require undercutting, so more tooth structure is left intact. This more conservative treatment can result in a stronger, longer-lasting restoration.
True or false: Non-metallic (tooth-colored) fillings are safer than silver fillings.
False. While each method has advantages and disadvantages, and may not be an appropriate treatment in every situation, both methods have been deemed safe and effective by major U.S. and international science and health organizations. While there have been recent concerns about mercury in amalgam fillings, there is presently no reason to believe that it presents any cause for concern.
If you would like more information about tooth-colored fillings, 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.”
What does the term “two-implant overdentures” mean?
For more than a century, complete dentures were the only care option for edentulous (toothless) people. As a solution, these left a lot to be desired, particularly for the lower jaw. Now dental technology has developed a better alternative that combines two strategically placed dental implants and a traditional lower denture that has been modified to fit over the two implants — thus the term.
What are the problems with traditional dentures?
The problem is that when you lose teeth, the bone that supported the missing teeth begins to shrink away. This is known as resorption, and it is the reason that dentures fitted too soon after teeth are lost quickly become loose. Bone loss happens most rapidly during the first year and is four times greater in the lower jaw than in the upper.
Why not just use dental adhesives to hold dentures tightly to the lower jaw?
Zinc, a major ingredient in most dental adhesives, has been associated with neurological disorders and may be unsafe. In addition, dental adhesives are expensive and the cost of frequent usage adds up.
Besides dental adhesives, are other health problems associated with dentures?
Yes, edentulism has been related to poor nutrition. Many edentulous people switch to soft foods with high fat content because they find healthier foods like vegetables and proteins difficult to chew.
What are dental implants?
Dental implants are replacements for the roots of teeth, the parts that are below the gumline and anchored in bone. They are usually covered with a crown that shows above the line of the gums.
What are the benefits of implants?
Most importantly, implants reduce the amount of bone resorption. Studies have shown about 75% less resorption in parts of the jaw with implants compared to areas without them. Since most of the bone loss occurs within the first year after tooth loss, it is important to place implants within this time period.
Is a complete set of dental implants a good solution for edentulism?
Yes, it can be a good solution, but it is not for everyone. Some patients, who have lost a great deal of bone support, need another solution for cosmetic reasons that offer more facial support like an implant overdenture. In addition, depending on their resources and insurance, some people require a less expensive solution.
Why does the two-implant overdenture work better for the lower jaw?
Based on differences in bone volume, density and other factors, we think that four to six implants are needed to retain an upper implant overdenture. Thus a two-implant overdenture is a good solution to consider for a lower jaw, but other options might be preferred for an upper jaw.
Contact us today to schedule an appointment to discuss your questions about dentures and implants. You can also learn more by reading the Dear Doctor magazine article “Implant Overdentures for the Lower Jaw.”