Dental Health and Tooth Fillings
To treat a cavity your dentist will remove the decayed portion of the tooth and then "fill" the area on the tooth where the decayed material was removed. Fillings are also used to repair cracked or broken teeth and teeth that have been worn down from misuse (such as from nail-biting or tooth grinding).
What Steps Are Involved in Filling a Tooth?
First, the dentist will use a local anesthetic to numb the area around the tooth to be filled. Next, a drill will be used to remove the decayed area. The choice of instrument depends on the individual dentist's comfort level, training, and investment in the particular piece of equipment as well as location and extent of the decay.
Next, your dentist will probe or test the area to determine if all the decay has been removed. Once the decay has been removed, the dentist will prepare the space for the filling by cleaning the cavity of bacteria and debris. If the decay is near the root, your dentist may first put in a liner made of glass ionomer, composite resin, or other material to protect the nerve. Generally, after the filling is in, your dentist will finish and polish it.
Several additional steps are required for tooth-colored fillings and are as follows. After your dentist has removed the decay and cleaned the area, the tooth-colored material is applied in layers. Next, a special light that "cures" or hardens each layer is applied. When the multilayering process is completed, the dentist will shape the composite material to the desired result, trim off any excess material, and polish the final restoration.
What Types of Filling Materials Are Available?
Today, several dental filling materials are available. Teeth can be filled with gold; porcelain; silver amalgam (which consists of mercury mixed with silver, tin, zinc, and copper); or tooth-colored, plastic, and glass materials called composite resin fillings. The location and extent of the decay, cost of filling material, patients' insurance coverage, and your dentist's recommendation assist in determining the type of filling best for you.
Silver Fillings (Amalgams)
Advantages of silver fillings:
Durability -- silver fillings last at least 10 to 15 years and usually outlasts composite (tooth-colored) fillings.
Strength -- can withstand chewing forces
Expense -- is less expensive than composite fillings
Disadvantages of silver fillings:
Poor aesthetics -- silver fillings don't match the color of natural teeth.
Destruction of more tooth structure -- healthy parts of the tooth must often be removed to make a space large enough to hold the amalgam filling.
Discoloration -- amalgam fillings can create a grayish hue to the surrounding tooth structure.
Cracks and fractures -- although all teeth expand and contract in the presence of hot and cold liquids, which ultimately can cause the tooth to crack or fracture, amalgam material -- in comparison with other filling materials -- may experience a wider degree of expansion and contraction and lead to a higher incidence of cracks and fractures.
Allergic reactions -- a small percentage of people, approximately 1%, are allergic to the mercury present in amalgam restorations.
Advantages of composites:
Aesthetics -- the shade/color of the composite fillings can be closely matched to the color of existing teeth. Composites are particularly well suited for use in front teeth or visible parts of teeth.
Bonding to tooth structure -- composite fillings actually chemically bond to tooth structure, providing further support.
Versatility -- in addition to use as a filling material for decay, composite fillings can also be used to repair chipped, broken, or worn teeth.
Tooth-sparing preparation -- sometimes less tooth structure needs to be removed compared with amalgam fillings when removing decay and preparing for the filling.
Disadvantages of composites:
Lack of durability -- composite fillings wear out sooner than amalgam fillings (lasting at least five years compared with at least 10 to 15 for amalgams); in addition, they may not last as long as amalgam fillings under the pressure of chewing and particularly if used for large cavities.
Increased chair time -- because of the process to apply the composite material, these fillings can take up to 20 minutes longer than amalgam fillings to place.
Additional visits -- if composites are used for inlays or onlays, more than one office visit may be required.
Chipping -- depending on location, composite materials can chip off the tooth.
Expense -- composite fillings can cost up to twice the cost of amalgam fillings.
Are Amalgam-Type Fillings Safe?
Over the past several years, concerns have been raised about silver-colored fillings, otherwise called amalgams fillings. Because these fillings contain the toxic substance mercury, some people think they are responsible for causing a number of diseases, including autism, Alzheimer'sdisease, and multiple sclerosis.
The American Dental Association (ADA), the FDA, and numerous public health agencies say there's no proof that dental fillings cause harm to consumers. The causes of autism, Alzheimer's disease, and multiple sclerosis remain unknown. Additionally, there is no solid, scientific evidence to back up the claim that if a person has amalgam fillings removed, he or she will be cured of these or any other diseases.
Although amalgams do contain mercury, when they are mixed with other metals, such as silver, copper, tin, and zinc, they form a stable alloy that dentists have used for more than 100 years to fill and preserve hundreds of millions of decayed teeth.
In June 2008, the FDA said, "Dental amalgams contain mercury, which may have neurotoxic effects on the nervous systems of developing children and fetuses."
And there's more. "Pregnant women and persons who may have a health condition that makes them more sensitive to mercury exposure, including individuals with existing high levels of mercury bioburden, should not avoid seeking dental care, but should discuss options with their health practitioner," according to the FDA.
The changes come in response to a lawsuit filed by consumer groups and individuals concerned about mercury exposure. To settle the suit, the FDA agreed to update its web site.
Problems With Dental Fillings
Tooth Pain and Sensitivity
Tooth sensitivity following placement of a filling is fairly common. A tooth may be sensitive to pressure, air, sweet foods, or temperature. Usually, the sensitivity resolves on its own within a few weeks. During this time, avoid those things that are causing the sensitivity. Pain relievers are generally not required.
Contact your dentist if the sensitivity does not subside within two to four weeks or if your tooth is extremely sensitive. He or she may recommend a desensitizing toothpaste, may apply a desensitizing agent to the tooth, or possibly suggest a root canal procedure.
Pain around the fillings can also occur. If you experience pain when you bite, the filling may be interfering with your bite. You will need to return to your dentist and have the filling reshaped. If you experience pain when your teeth touch, the pain is likely caused by the touching of two different metal surfaces (for example, the silver amalgam in a newly filled tooth and a gold crown on another tooth with which it touches). This pain should resolve on its own within a short period of time.
If the decay was very deep or close to the pulp of the tooth, you may experience a "toothache-type" pain. This "toothache" response may indicate this tissue is no longer healthy. If this is the case, a root canal may be required.
Sometimes people experience what is known as referred pain -- pain or sensitivity in other teeth besides the one that received the filling. With this particular pain, there is likely nothing wrong with your teeth. The filled tooth is simply passing along "pain signals" it's receiving to other teeth. This pain should decrease on its own over 1 to 2 weeks.
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