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Tooth preparation

Restoring a tooth to good form and function requires two steps:

The process of preparation usually involves cutting the tooth with a rotary dental handpiece and dental burrs, a dental laser, or through air abrasion (or in the case of atraumatic restorative treatment, hand instruments), to make space for the planned restorative materials and to remove any dental decay or portions of the tooth that are structurally unsound. If permanent restoration cannot be carried out immediately after tooth preparation, temporary restoration may be performed.

The prepared tooth, ready for placement of restorative materials, is generally called a tooth preparation. Materials used may be gold, amalgam, dental composites, glass ionomer cement, or porcelain, among others.

Preparations may be intracoronal or extracoronal. Intracoronal preparations are those which serve to hold restorative material within the confines of the structure of the crown of a tooth. Examples include all classes of cavity preparations for composite or amalgam as well as those for gold and porcelain inlays. Intracoronal preparations are also made as female recipients to receive the male components of removable partial dentures. Extracoronal preparations provide a core or base upon which restorative material will be placed to bring the tooth back into a functional and aesthetic structure. Examples include crowns and onlays, as well as veneers.

In preparing a tooth for a restoration, a number of considerations will determine the type and extent of the preparation. The most important factor to consider is decay. For the most part, the extent of the decay will define the extent of the preparation, and in turn, the subsequent method and appropriate materials for restoration.

Another consideration is unsupported tooth structure. When preparing the tooth to receive a restoration, unsupported enamel is removed to allow for a more predictable restoration. While enamel is the hardest substance in the human body, it is particularly brittle, and unsupported enamel fractures easily.

A systematic review concluded that for decayed baby (primary) teeth, putting an off‐the‐shelf metal crown over the tooth (Hall technique) or only partially removing decay (also referred to as "selective removal") before placing a filling may be better than the conventional treatment of removing all decay before filling. For decayed adult (permanent) teeth, partial removal (also referred to as "selective removal") of decay before filling the tooth, or adding a second stage to this treatment where more decay is removed after several months, may be better than conventional treatment.