A dental restoration or dental filling is a dental restorative material used to restore the function, integrity and morphology of missing tooth structure. The structural loss typically results from caries or external trauma. It is also lost intentionally during tooth preparation to improve the aesthetics or the physical integrity of the intended restorative material. Dental restoration also refers to the replacement of missing tooth structure which is supported by dental implants.

Dental restorations can be divided into two broad types: direct restorations and indirect restorations. All dental restorations can be further classified by their location and size. A root canal filling is a restorative technique used to fill the space where the dental pulp normally resides.

Tooth preparation

Tooth preparation is usually required before placing a dental restoration. This process involves cutting the tooth usually with a dental drill to make space for the planned restoration, remove any dental decay and structurally unsound tooth. If permanent restoration can not be carried out after tooth preparation, temporary restoration is done. A tooth preparation is the finished product of a tooth's structure prior to restoration with a dental restorative material, such as gold, amalgam, composite, porcelain or any number of other materials.There are two types of preparations.

1. Intracoronal Preparations are those preparations 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.

2. Extracoronal Preparations are those preparations which serve as a core or base upon which or around which restorative material will be placed to bring the tooth back into a functional or aesthetic structure. Examples include crowns and onlays, as well as veneers. In preparing a tooth for a restoration, a number of considerations will come into play to 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.

Various restoration are

1. Amalgam Fillings ( Silver Fillings ): Amalgam fillings are also named as silver fillings. They are prepared by amalgamating the silver, tin and copper alloy with mercury. Mercury makes 45%-50% of the compound and acts as a bond between the metals resulting in a highly strong filling. Amalgam which is improved through the almost 150 years that is on the market has widely served and is still serving to maintain teeth in mouth.

2. Glass Ionomer Cement: As they bond chemically to dental hard tissues and release fluoride for a relatively long period modern day applications of GICs have expanded. The desirable properties of glass ionomer cements make them useful materials in the restoration of carious lesions in low-stress areas such as smooth-surface and small anterior proximal cavities in primary teeth. Results from clinical studies also support the use of conventional glass ionomer restorations in primary molars. They need not be put in layer by layer, like in composite fillings.

3. Composite Fillings( Tooth coloured fillings): They are esthetic restorations that are generally used in the front teeth. But for the past two or three decades there have been tremendous improvements in the chemistry and bonding properties of those fillings so that nowadays even at the back molar teeth we confidentely are placing composite fillings because of their high strength capacity against occlusal forces.

4. Inlays-Onlays: Inlays and onlays are fabricated, casted restorations that are indicated for very large tooth losses which otherwise need to be crowned. After removing the decay and shaping the cavity impressions are taken and sent to the laboratory for either gold, composite or porcelain inlays and onlays. After they arrive from laboratory they are bonded in place with special cements and techniques. They require special and precise techniques.