General Dentistry Concepts: Dental restoration
A dental restoration or dental filling is a treatment used to help restore the function, integrity, and morphology of a compromised tooth structure. This can be the result of dental caries, external trauma or the replacement of such structure which is supported by dental implants. They are of two types of dental restorations which include direct and indirect. Restorations are further classified by their location and overall size. As an example, a root canal filling is a restoration where filling is placed in the space where the dental pulp normally exists.
Tooth Preparation
Restoring a tooth typically includes two steps which include:
- Preparing the tooth for the placement of the restorative material(s)
- Placement of the restorative material(s)
Preparing the tooth usually involves cutting the tooth down with a rotary dental hand piece and dental burrs or a dental laser. This helps ensure there is adequate space for the restorative materials and also removes any decay or weak portions of the tooth. In cases where permanent restoration cannot be completed immediately following tooth preparation, the dentist may use a temporary restoration.
Materials which are often used for restoration procedures can include gold, amalgam, dental composites, glass ionomer cement, porcelain and other options. Preparations may be considered intracoronal or extracoronal. An intracoronal preparation holds restorative material within the confines of the structure of the crown of a tooth. Examples of when intracoronal preparation may be used include treating a cavity with composite or amalgam filling in addition to gold and porcelain inlays. Intracoronal preparations are also used to receive removable partial dentures. Extracoronal preparations act as a core or base where restorative material is placed to restore the tooth’s function and aesthetic structure. Examples of extracoronal preparations include crowns, onlays and veneers.
When the dentist prepares the tooth for a restoration, various considerations help determine what is needed. The most critical factor to consider is the amount and location of any tooth decay. The extent of the decay determines the extent of the preparation required in addition to the method and materials used for restoration.
Another consideration is the presence of any unsupported tooth structure. When the tooth is prepared to receive a restoration, unsupported enamel is removed to ensure the restoration is predictable and the surface is adequate. While tooth enamel is the hardest substance in our body, it is also extremely brittle and can fracture easily.
Direct restorations
Direct restorations involve placing a soft or malleable filling into a prepared tooth in order to build up the tooth. As the material sets, is hardens and the tooth is restored. Direct restorations can be advantageous because they set quickly and can be placed in one procedure. Dentist have numerous different filling options to choose from depending on the case. Decisions regarding the material used is often determined based on the location and severity of the cavity. Because the material sets while it is in contact with the tooth, limited heat is passed to the tooth as a result of the setting process.
Indirect restorations
When using this technique, the restoration is fabricated outside of the mouth using impressions of the prepared tooth. Common indirect restorations can include crowns, bridges and veneers. A dental technician will typically fabricate the indirect restoration from records and impressions provided by the dentist. The final restoration is usually permanently bonded using a dental cement. This process is often completed in two separate visits. Indirect restorations are commonly completed using gold or ceramics.
