Procedures

Fillings & core buildups

Procedure overview

Alternate terms: Preventive resin restorations.

Fillings are among the most frequently prescribed and versatile of all dental restorations. In a procedure known as cavity preparation, the dentist uses any of a variety of dental drills (also called "burs") to remove damaged tooth structure, and any tooth material that has been weakened or undermined by decay. Applying their knowledge of ideal tooth shape ("morphology"), dentists replace the missing tooth structure with filling material of various types.

Fillings are placed into teeth following the removal of decay ("caries"), and are also used to restore chipped or partially broken teeth to their normal contour and function.

When performed traditionally, a mixture of silver, zinc, copper and mercury known as "amalgam" is used to fill the back teeth, and even the front ones if the decay is on a surface that does not show when the patient smiles. Although they can be bonded into the tooth with modern dental adhesives, silver fillings are held into the tooth primarily by mechanical interlocking features cut into the tooth by the dentist.

Silver "mining" is a term with negative implications, describing the removal of clinically sound silver fillings for reasons having no solid basis in science or medicine. If you've been told you need all of your silver fillings replaced in a short time frame, be certain you understand the reasons. If you are having it done for cosmetic reasons, be sure you understand the risks.
Learn more: Diagnoses › Failing restorations
Learn more: Diagnoses › Poorly contoured dental restorations

Beginning in the 1960's a process known as "bonding" was developed. Since its inception, dental bonding has continued to improve in strength and durability, allowing teeth to be more conservatively restored. Modern bonding materials may allow teeth that have been structurally compromised to be repaired with long-lasting and cosmetically pleasing fillings. A tooth-colored material known as composite resin is currently used to restore many cavities—even those found in the back teeth (Figures 2, 3, and 4).

Additional information

Core Buildups

If all or most of the natural anatomic crown of a tooth (i.e. the part that you can see protruding through the gums) is missing (due to decay, trauma, etc.), but the tooth is still considered fixable, a special type of filling procedure known as a "core buildup" is performed. After the core has been rebuilt, the tooth is frequently prepared for a crown to prevent the core buildup and tooth from splitting apart. The amount of time that elapses between the core buildup procedure and preparation for a crown varies. Many people wait years to have a crown placed.

The core buildup process is identical to cavity preparation, except that more of the tooth is involved (corners and/or sides of the tooth are missing). This often requires the use of reinforcing pins and posts to help hold the filling material into the tooth. If CDT code D2950 is used to report the crown buildup procedure, any pins used for reinforcement are considered to be included in the price, and you should not be charged separately for them. Billing separately for pins is considered "Fee Unbundling", which adds unnecessary cost to the procedure.

A core buildup can often be performed in such a way that the tooth's natural anatomic contours, natural function with its opposing tooth, and contact with its neighbors are restored. If so, the core buildup can be an excellent long-term provisional restoration while the patient plans for the expense of crowning the tooth. This is particularly useful if the patient requires other dental work to be done.

Fillings in Primary Teeth

People often wonder why primary teeth should be filled if they're "just going to fall out anyway." Baby molars need to be maintained in the mouth until they naturally loosen and come out around age 11 to 13 (with wide individual variation). This is because they prevent the permanent six-year molars from drifting forward in the mouth and "blocking" the eruption pathway of the (permanent) bicuspid teeth. As primary molars near the time when they are to exfoliate (i.e. fall out), they can be evaluated individually to gage whether any decay that might be present will progress through the tooth fast enough to cause problems before they fall out.
Learn more: Procedures › Space maintainers

Filling a tooth that will soon be lost is overtreatment. Sometimes the dentist may recommend removing a primary tooth with a large cavity to eliminate the bacteria it contains. If the permanent tooth under it is close to coming in, nothing further needs to be done. There is a CDT code (D7111) specifically for the removal of the "coronal remnants" of a primary tooth. This means, if the baby tooth has little root structure remaining, you should not be charged for an "elevator and forceps" (i.e. "Simple") extraction, Code D7140, or surgical extraction, which would normally require more work to remove and would likely cost more.

While restoring the primary molars is important, any of the front six primary teeth can generally be lost without long term consequences to the patient's dentition. Decay on the front teeth should definitely be removed when present (tooth decay is a bacterial illness that should not be left untreated), but restoration of those teeth may not be necessary if the permanent teeth are present in the jaw and expected to come into place normally.

Generally the front four ("incisor") baby teeth in each jaw have been lost by age 9 (frequently as early as age 6-7) and replaced with the permanent teeth. Also, it is common practice to remove by sandpaper disk, 1-2 mm of tooth structure from the front ("mesial") side of the primary canine teeth (the third tooth over from the center in each quadrant of the mouth) without placing any filling material over the cut surface, in order to allow crowded permanent incisor teeth the space to straighten themselves out passively (without help). By extension of this concept, it is often possible to remove 1-2mm of decayed tooth enamel from the "interproximal" surfaces (the sides adjacent to the neighboring teeth) of the primary front teeth without restoring them at all.

If your child has decay on their front teeth, be sure to discuss this with your dentist, who is the only one who can tell you for certain whether your child's front teeth can be treated ultra-conservatively in this way. It will depend on the extent of decay, the age of the child, and the presence or absence of permanent teeth in the jaw to replace the primary teeth. This information is provided only to generate awareness of what may be possible, not to diagnose or provide specific treatment information for your child.

Tooth decay in children is normally treated the same as in adults. The decay is removed from the tooth, and the missing tooth structure is filled with any of a variety of dental restorative materials. Options generally include fillings (silver amalgam, composite resin and glass ionomer), and prefabricated crowns (generally made of stainless steel or plastic).

Silver fillings contain about 50% mercury by weight. Mercury may have toxic effects on the nervous systems of developing children and fetuses. Mercury vapor is also released from silver fillings when they are removed from teeth, and to some extent during chewing. For these reasons, use of silver fillings containing mercury has been called into question by various groups. Their use has been banned in some countries. Currently, the USA is not one of them.

As of June, 2008, The U.S. Food and Drug Administration is in the process of reclassifying silver fillings, and in rulemaking that may lead to revised labeling. It is also reviewing evidence about safe use of dental amalgam, especially in certain subpopulations. These include pregnant or lactating women; children under the age of six; and certain immune compromised individuals.

The advantages (low cost, high durability) of silver amalgam should be carefully considered against the possible health risks until more information is available. It is estimated that between one third and one half of all American dentists no longer use silver amalgam containing mercury, in favor of composite resin and/or glass ionomer materials. Porcelain and gold are rarely used restorative materials in pediatric dentistry due to their cost.

Caries detection and diagnosing the need for fillings

A recently introduced and extremely sensitive diagnostic tool for determining whether the pits and fissures in teeth have begun to decay at their base is the laser flourescence caries detection device. Healthy teeth do not fluoresce, and decayed teeth fluoresce in direct relation to the amount of bacteria present in the tooth. Laser caries detection devices measure the fluorescence pattern of teeth, and produce a reading on a meter which is recorded by the dentist.

Important information about the manufacturer's recommended use of this device can be found in the glossary entry for laser caries detection. Familiarizing yourself with this simple information can help you understand when treatment is suggested.
Learn more: Glossary › Laser caries detection

Post-operative discomfort

A common misconception about teeth is that working on them, like trimming fingernails, should not lead to any complications. In reality, though, working on teeth is a surgical procedure. Teeth are very well-supplied with two different types of nerve tissue. And unlike other tissues of the body that are living, teeth can't swell, and are poorly equipped to deal with inflammation. Working on teeth very commonly produces inflammation—just as making an incision in an arm or leg would. Inflammation is a process by which your body sends immune cells and healing cells to the affected area so that they can repair the "wound". It does so by increasing blood flow to the affected region.

When the surgery is performed on soft tissue (i.e. skin, muscle), increased blood flow to the area produces swelling—enlargement of the soft tissues—which are somewhat elastic (i.e. "stretchy"). Since teeth cannot swell, inflammation causes the blood pressure inside the tooth to increase. The increased pressure on the nerves inside may produce significant discomfort. Well-maintained dental instrumentation, skilled technique, and use of desensitizing medications can minimize post-operative discomfort, but may not eliminate it.
Learn more: Diagnoses › Irreversible pulpitis
Learn more: Diagnoses › Reversible pulpitis

Anything that causes a pressure change inside an inflamed tooth can provoke more discomfort. The most common culprits are cold temperatures and chewing. Cold causes the fluid inside the tooth to contract (shrink), changing the pressure. Chewing sends small hydraulic compression waves through the extra fluid in the tooth, and these pulses are perceived as pain. Sensitivity to heat is a symptom in some cases, but generally heat sensitivity is less common. Severe sensitivity to heat is a sign that there may be gas in the tooth. This is an unfavorable situation, because the gas is usually produced by bacteria (i.e. the tooth is infected). Sometimes the only way to reduce the pressure in the tooth is to make a hole into the pulp space (i.e. perform a root canal).
Learn more: Diagnoses › Acute apical abscess

Some people are inclined to think something must have been done wrong if they experience discomfort after a dental procedure. Although this can be the case, if proper procedure is followed, it is more likely the tooth's reaction to what was done that causes the problem. Does this mean you should wait until your tooth hurts to fix a problem that has been diagnosed? Definitely not! Very often problems with teeth (i.e. cavities, etc.) don't hurt unless they are advanced. Waiting until the problem is advanced to fix it is a big mistake. The bigger the problem is, the harder it is to fix and the more likely it is to produce complications; and it will frequently have a poorer prognosis (likelihood of long-term success) if you wait too long to have a problem fixed.

If your dentist can show you the problem (e.g. on the X-ray, with a photo, etc.) in such a way that you have a clear understanding of what it is, how it can be fixed, with how much urgency it should be addressed, any options you may have for fixing it, the risks, and intended benefits of each, the likelihood of success ("prognosis") of each, and the cost of each, you will experience better treatment outcomes.

Why does food collect between my teeth now? It didn't use to.

Decay or chips in a surface of the tooth that contacts the adjacent teeth present a restorative challenge: Rebuilding the damaged surface so that it's smooth, and touches the neighboring teeth with an appropriate contact. You can tell if there is a contact between your adjacent teeth with floss—if the floss meets no resistance going between the teeth and goes all the way to the gums, there is no contact.

Some people have natural spaces between their teeth. These open contacts are called diastemas, and if they are kept clean, usually don't cause problems. However, if you had a contact between the teeth and no longer do following a tooth restoration (filling, crown, inlay or onlay), an open contact has resulted and generally will need to be fixed. What to do about open contacts depends on where in the mouth they are located, the type of tooth restoration that was done, and what type of restoration (if any) is present on the adjacent teeth.

Restoring a tooth's "interproximal" contact (the one it makes with its neighbors) requires two things:

1. A band (called a "matrix band" placed around the tooth to serve as a temporary form for the filling material, in order to reproduce the tooth's natural convex contours.
2. A way to compensate for the thickness of the matrix band when it's removed, such that a gap the thickness of the band does not remain. This is done by applying light forces between the tooth that is being worked on and its neighbors, to squeeze them away from each other a bit. The idea is that the adjacent teeth be temporarily tipped away from the tooth being worked on enough that when the squeezing forces and matrix band are removed, the teeth will return to their normal position and will again be in contact with the "interproximal" surfaces of the filled tooth.

It is always better and sometimes possible to anticipate an open contact in advance. In general, open contacts can be anticipated as follows:

• If there is not enough tooth present after damaged tooth structure is removed to allow the dentist's squeezing instruments to apply adequate separation force, an open contact can result.
• If the teeth on either side of the tooth being worked on require greater force to tip them aside than the squeezing instruments can develop, an open contact may result.

Common situations leading to open contacts include the following:

• Building a filling against a tooth that serves as a bridge retainer. This is because applying tipping force to a bridge retainer tooth generally doesn't move it very much. Since it's rigidly connected to another tooth at the other end, at least twice as much squeezing force is required to tip it.
  Learn more: Procedures › Fixed partial dentures
• Building a filling against a dental implant that has been restored with a crown. This is because dental implants are rigidly fused to the jaw bone, and don't move at all when tipping forces are placed on them.
  Learn more: Procedures › Dental implants
• Building a filling against a molar tooth with broad / large roots, or one that is tipped forward in the mouth. Instruments used to squeeze separate adjacent teeth have a harder time tipping molars.
• Large areas of decay and large chips involving a surface that normally touches the neighboring tooth. This is because too little tooth structure remains to push against with the squeezing instrument, in order to move the tooth enough to compensate for the thickness of the matrix band.
  Learn more about open contacts: Diagnoses › Food compaction injuries

Clinical Urgency for Replacement of Fillings

Whether to replace a filling with urgency depends on several factors:

• Whether it's cracked, broken, or merely "ditched"
• Pain / sensitivity status of the tooth
• Presence of decay under or along the filling
• Leakage past the filling
• Size and depth of the filling
• Patient's overall treatment plan
• Age and health of the patient

If the filling is cracked or broken, and the tooth is sensitive, or has decay under or along the filling, the tooth should be restored as soon as possible. If the filling is cracked or broken, and the tooth is not sensitive, has no decay, and the filling is not large, the urgency to restore it may not be as great. However, it should ultimately be done to prevent problems from arising. Sometimes a patient's general health status or prognosis does not justify putting them through the time, expense, or potential discomfort of extensive dentistry; however, if it is truly necessary, replacing fillings may generally be accomplished without a lot of discomfort. Some examples of clinical urgency follow to give you an idea of how yours might compare. Talk it over with your dentist.

Figure 8: The silver filling in the back tooth is cracked (see arrow). This is a large filling, in the most highly stressed tooth in the jaw. Restoring the tooth's structural integrity should be a priority for this patient, although they may have several options for doing so. A "core buildup" can be done, removing the old filling material and any underlying decay, and replacing it with new filling material. Greater longevity may be obtained by placing a crown or onlay on the tooth, once the core has been rebuilt.

Although the next tooth forward has a very large silver filling in it, crowning that tooth (or otherwise restoring it) is of lower urgency because the existing restoration is intact and has provided the patient with years of trouble-free service.