Posterior Treatment Options

By Brian J. Gray, DDS, MAGD, FICOI

Currently, there is an abundance of options available for restoring back teeth. These options can vary both in material (tooth-colored vs. metal) and in the amount of treatment time needed to place the fillings. The two main categories of restorations are "direct" and "indirect" techniques.

When is one technique chosen over another? Mainly, it depends on how big the restoration needs to be compared to the size of the tooth. Generally, the materials used for the direct technique are structurally not as strong and, hence, need to be used in situations where they can be kept small in order for them to have the best chance of lasting. If the restoration needs to be larger to cover more of the tooth, it will also need to be stronger. The materials used for the indirect technique would then be required.

Direct Technique

The direct technique consists of fabricating and placing the filling directly on the tooth. This procedure only requires a single office visit, where the old filling or cavity will be removed followed by the placement of the new filling. In this category, there are mainly two options available: amalgam -- a silver-colored filling material, or composite -- a tooth-colored filling material.

Amalgam

Amalgam has been around for many years and is considered a very durable and long-lasting material. It is not being used as often today for one main reason: esthetics. Many people do not want to have the appearance of metal in their mouth. Another possible reason why the use of amalgam is on the decline is the fact that it contains mercury, although the amount of mercury leaching out of the material once it is in the mouth is still questionable. One of the advantages of amalgam is that it is the strongest direct filling material available. Since the material itself is so strong, it can be used in a variety of situations, especially with regards to size. Because of its strength, amalgam can be used predictably in situations that would normally require indirect techniques.

Composite

Composite is a plastic tooth-colored filling material. It is the most common direct filling material used today and its use is continually growing, as more people are concerned about esthetics. Since it relies on a "bond" with the tooth structure, it can be used in a manner that is more conservative, in that the amount of tooth structure that needs to be removed is less than with amalgam. To ensure the most predictable long-term result, this material needs to be used for smaller fillings. Composite is not as strong as amalgam and is more prone to wear over time.

Indirect Technique

The indirect technique requires more than one appointment. This technique involves removing the old filling or decay; but rather than immediately placing the new filling, an impression is made of the tooth so that the final restoration can be made outside of your mouth on a model of your tooth. A temporary filling is then placed until the final restoration is finished and can be placed at the second appointment.

There are also many options available to restore teeth utilizing the indirect technique. These include gold or tooth-colored materials. Again, the advantages of this technique are an increase in strength and the ability to better control the function, contour and esthetics of the final restoration. These restorations can vary in size from an "inlay," which fits within the confines of the tooth, to an "onlay," which covers the top half of the tooth, to a "crown," which covers the entire tooth. Ideally, the restoration of choice will be the one that satisfies the requirement of why the tooth needed a restoration in the first place while only removing as much tooth structure as necessary. Typically, an inlay is more conservative than an onlay, which is more conservative than a crown. All of these restorations are then either bonded or cemented to the tooth.

Gold Inlay/Onlay

Gold has been used for dental restorations for many years. It is extremely strong, resistant to wear, and can achieve an excellent fit. Also, since it is metal, it is very resistant to fracture. However, as with amalgam, the problem is with the esthetics in that most people do not want to show the gold.

Tooth-Colored Inlay/Onlay

The materials used in this category can vary from porcelain to resin, both of which can be used with a high degree of success. These restorations have superior esthetics and are able to blend naturally with your own teeth. Porcelain is by far a stronger material and less likely to wear than resin. Due to the nature of these materials as compared with gold, they are at a higher risk for fracture. However, if designed well, these restorations are very durable.

Crown

Crowns are used to help cover and contain teeth that are in need of structural support. They can be used in any situation and can be fabricated out of either gold or porcelain with a metal substructure. Also available are all-ceramic crowns, which do not have any metal. All-ceramic crowns are primarily indicated in the front of the mouth, as they have an increased risk of fracture when used on the back teeth. If a tooth-colored crown is indicated for restoring a back tooth, a better choice is a porcelain crown with a metal substructure. Its strength and fracture resistance make it more durable in the back teeth where there are more forces from chewing.