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Tooth decay is one of the most common diseases globally, and if you have teeth, you are not immune to it. The decay is caused by acids from bacteria that create tiny holes in tooth enamel and exposed root surfaces. It can also be caused by acids in the food you eat and beverages you drink.

Left untreated, tooth decay progresses into the next layer of the tooth called dentin, which is softer and less resistant to acids. When this happens, your tooth may become more sensitive.

Without proper treatment, the decay will progress into the inner portion of your tooth (the pulp), where the nerves and blood vessels are. The bacteria irritate the pulp tissues, and the pulp can become infected and start to swell. Because tooth structure is hard, the swollen tissues have no room to expand, and pressure builds inside the tooth. The pressure then compresses the tooth nerve, resulting in pain. In severe cases, the infection can progress into your jawbone, leading to missing teeth and other medical and dental issues.

If your tooth is damaged by tooth decay, a filling is normally recommended to restore your tooth to its normal shape, function, and appearance. Fillings are also used to fix chipped teeth or partially broken teeth.

There are five different surfaces on a tooth that can be repaired with a filling. The more surfaces a filling needs to cover (even if it's just a portion of one or more surfaces), the more complex it is to place the filling. In any case, your dentist's goal will be to maintain as much of your original tooth structure as possible.

The benefits of fillings include:

  • Restoring a decayed tooth to its normal shape and function.
  • Removing decay and reducing the number of bacteria in your mouth.
  • Preventing tooth decay from affecting your jawbones.
  • Avoiding further decay can lead to pain, swelling, root canal therapy, or missing teeth.
  • Preserving healthy tooth structure as opposed to more intrusive treatments such as a crown).
  • Helping to prevent unwanted tooth movement and changes in your bite.
  • Maintaining your smile.

Fillings are typically made of amalgam or composite resin materials. Your dentist will recommend the best option for you based on:

  • The number of decayed teeth.
  • The location of the fillings in your mouth.
  • The extent of the repair.
  • Allergies you may have to certain materials.
  • Your desire to maintain the natural appearance of your teeth.
  • Your budget.

Amalgam: Amalgam fillings are durable and resistant to wear. They are darker in color than other filling materials, which means they are more noticeable. They are not usually used on teeth that are more visible when you talk and smile. Amalgam fillings typically last from 10 to 15 years,1 or longer if they are well placed and properly maintained with good oral hygiene. Changes in your oral habits, or conditions such as dry mouth, or habits such as grinding or clenching your teeth, can shorten this timeframe.

Composite resin: Composite fillings can be color-matched to the same shade as the adjacent teeth and result in a more natural appearance. However, they can become stained from products such as coffee, tea, or tobacco. They may wear faster than other filling materials and may also chip more easily. Composite fillings do not tend to last as long as amalgam fillings (typically up to 10 years).1

In addition to regular dental exams and professional tooth cleanings, you can extend the life of your fillings by:

  • Maintaining good nutrition.
  • Practicing good oral hygiene.
  • Avoiding sticky or chewy foods that may loosen your filling.
  • Not chewing ice or hard foods that can damage your fillings.
  • Keeping your dentist informed about any changes in your health history.

A filling procedure varies based on your circumstances and preferences and the methods used by your dentist. The general steps are:

Before the procedure

  • Review your health status: You will share information that will help ensure that your dentist and their staff can provide safe and effective treatment and provide appropriate post-care guidance. Get important information here: Health history and current health status.
  • Treatment review: Your dentist will review the procedure with you, including its risks, benefits, and options you may have. Understanding the process will lead to the best treatment outcome. Ask any questions you have before committing to the procedure.
  • Anti-anxiety medication: If you are anxious about dental procedures, your dentist may recommend sedation.

During the procedure

  • Antiseptic: Some dentists use an antiseptic solution to kill bacteria prior to preparing your tooth for the filling.
  • Anesthetic: Depending on the depth of the tooth decay or other factors, your dentist may be able to place a filling without any local anesthetic. If the decay is deep or widespread, a local anesthetic may be applied. A topical numbing gel may also be applied to the site to help reduce the discomfort of the injection. If you would like to avoid local anesthetic, discuss it with your dentist before the procedure begins.
  • Infection control: Once the tooth or teeth are numb, your dentist may isolate the area with a rubber dam to help prevent infection.
  • Preparing the tooth:
    • Your dentist will remove the tooth decay and the weakened tooth structure using a variety of mechanical or electronic instruments.
    • After your dentist removes all of the obvious decay and the areas are prepared to retain a filling, your dentist may use detection dye. This leaves a stain on the less obvious areas of decay to allow your dentist to remove any remaining decay without removing additional tooth structure.
    • Your dentist may apply a base or liner to insulate or medicate the tooth pulp with deep tooth decay.
    • If you are getting a composite filling, your dentist will etch the preparation area with an acid solution. They may also use compounds that reduce tooth sensitivity.
    • Your dentist will then place the filling.
    • If you are getting a composite filling, your dentist will use a blue light to harden the filling material.
    • Your dentist will check your bite to ensure proper contact between the teeth and adjust the filling if needed.
    • Finally, your dentist will polish the filling and tooth.

After the procedure

Your dentist will give you specific instructions on how to take care of your fillings. You should request a copy of the instructions. Although the instructions may seem straightforward at the time of your dental appointment, you may have questions and need to refer to them later.

After you leave the dentist's office and while you are still numb:

  • Do not eat or drink hot beverages while your lips, cheeks, or tongue are numb. It is possible to bite or burn yourself without realizing it.
  • Do not pull on or poke at the numb areas in an attempt to make the feeling return. There is no way for you to reduce the period of numbness. Sensation usually returns within 1-2 hours, but the amount of time that passes until feeling returns depends on the type of anesthetic used and other factors.
  • You may experience slight difficulty with your speech until the anesthetic wears off.

Additional services you may need

Depending on the extent of your tooth decay, you may also require:

  • Be sure to specifically mention if you have allergic reactions to any metals. This information will help inform your dentist about the most appropriate material to use.
  • Preparing teeth for fillings involves the removal of both diseased and healthy tooth structure, which can further weaken the teeth.
  • You may experience discomfort during or after the procedure. Generally, this is minor and easily controlled with over-the-counter pain relievers.
  • There are risks associated with a local anesthetic.
  • You may experience tooth sensitivity to biting, cold, or heat following the procedure. Normally this is temporary. If your tooth sensitivity does not go away, your tooth may require root canal therapy.
  • You may experience inflammation of the tooth pulp, which may be temporary (reversible pulpitis) or permanent (irreversible pulpitis). The risk of developing irreversible pulpitis or an infection (abscess) is greater if your dentist places bonded fillings in a tooth without adequately isolating the tooth from moisture (saliva, rinsing water, etc.).
  • While rare, it is possible that your tooth pulp or the surrounding gum tissues can become infected following the procedure. This risk is generally greater when the decay extends deep inside the tooth or below the gum line. Risk factors for infection may include your age, the strength of your immune system, and whether the tooth has had previous dental work.
  • Large fillings involving surfaces that touch the adjacent teeth may result in a gap that may lead to a food compaction injury. When this happens, the filling may need to be replaced or restored with an inlay, onlay, or crown.
  • Poorly contoured fillings may shred dental floss and collect food, leading to inflammation of the periodontal tissues and a recurrence of decay in the tooth.
  • Fillings can wear or break and may need replacement, especially if your health, habits, or medications change.

Replacing fillings

  • If you or your dentist notices a change in your filling, you may not need to have it replaced right away. However, replacing fillings can generally be accomplished quickly and without much discomfort or expense.
  • Cracked or broken fillings should be replaced right away. If a small filling is cracked or broken, but your tooth is not sensitive, you may have a little more time to replace it, though it is generally not a good idea to wait for your teeth to become sensitive before taking care of the problem.
  • Fillings should be replaced quickly if your dentist finds tooth decay under or along the edge.

Some people may want to replace all of their amalgam fillings at once. This can be for cosmetic reasons or because they are concerned about mercury in the fillings. It's important to know that the trace amounts of mercury in fillings have no effect on the body after the filling has hardened in the tooth. Mercury does become vaporized when fillings are removed, which increases your exposure.

Replacing any filling also requires the removal of additional healthy tooth structure, which should be avoided for as long as possible.

If your dentist tells you that many or all of your amalgam fillings need to be replaced in a short time frame, make sure you are aware of the possible risks and concerns. Your dentist is aware of potential risks and will discuss your options to achieve the best outcome for your oral health and your expectations.

Fillings for primary teeth

If your dentist diagnoses tooth decay in your child's primary teeth, it is especially important to determine the urgency for filling them. Before you agree to have your child's primary teeth filled, be sure to discuss the following situations.

  • If the amount of decay can be controlled through cleanings and good oral hygiene before the tooth naturally falls out, you may be able to avoid the time, expense, and discomfort of having the tooth filled.
  • In some cases, permanent teeth do not appear under certain primary teeth (congenitally missing teeth). Your dentist will be able to see this through X-ray images. In these cases, primary teeth may remain in your child's mouth for a long time and should be maintained as if they were permanent teeth.

There may be alternatives to a filling depending on the extent of your tooth decay or the severity of the chip in your tooth.

When considering alternatives to fillings, your objective should be to preserve as much original tooth structure for as long as possible. This is because any restoration to your tooth will fail eventually and need to be replaced. When any restoration is replaced, healthy tooth structure may need to be removed for the next restoration. If you can address your tooth decay with a filling, it is generally the smartest and most economical treatment alternative.

Allowing tooth decay to go untreated will result in the destruction of healthy tooth structure and the need for more extensive dentistry. Deep decay may extend into the tooth pulp, which may require root canal therapy. Your dentist may also recommend a crown or onlay following root canal therapy.

If left untreated, the bacteria in a deep cavity will eventually reach the pulp and have an open pathway into your jawbone. This can cause pain, swelling, or numbness. It can also lead to tooth loss or the need for tooth removal.

Though rare, infections resulting from advanced tooth decay can be deadly and can also affect other medical conditions you may have.

  • Do you think it's possible that the tooth can be restored through remineralization without placing a filling?
  • Are there any appropriate treatment options that you can recommend? What are the pros and cons of a filling versus those options?
  • What caused my tooth decay? What can I do to avoid future decay?
  • How deep is my tooth decay? Will it require a base or liner to protect the pulp inside the tooth while performing the procedure?
  • How many surfaces of my tooth does the filling need to cover?
  • Since the filling is needed on my back tooth, should I consider an amalgam filling? In your opinion, would amalgam or composite resin be more appropriate?
  • You are suggesting that I need an existing filling replaced. Why do I need to have it replaced? What is the urgency for replacing it? What problems could arise if I don't have my filling replaced?
  • What can I do to make my fillings last as long as possible?
  • Does my child's primary tooth need to be filled, or can the procedure wait until it falls out?

Author: Symbyos staff, Fluent staff
Last updated: 5/3/2021Medical review: Thomas J. Greany DDS, 12/28/2020
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