A filling is a way to restore a tooth damaged by decay back to its normal function and shape. Dentist first removes the decayed tooth material, cleans the affected area, and then fills the cleaned out cavity with a filling material. 

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

• Preparing the tooth for placement of restorative material or materials
• Placement of these materials.

The process of preparation usually involves cutting the tooth with a rotary dental handpiece and dental burrs, a dental laser, or though air abrasion to make space for the planned restorative materials and to remove any dental decay or portions of the tooth that are structurally unsound.

Type of Filling

Amalgam (silver) fillings: Dental amalgam is a dental filling material used to fill cavities caused by tooth decay. Dental amalgam is a mixture of metals, consisting of liquid  (elemental) mercury and a powdered alloy composed of silver, tin, and copper. Approximately half (50%) of dental amalgam is elemental mercury by weight. When placing dental amalgam, the dentist first drills the tooth to remove the decay and then shapes the tooth cavity for placement of the amalgam filling. Next, under appropriate safety conditions, the dentist mixes the encapsulated powdered alloy with the liquid mercury to form an amalgam putty. This softened amalgam putty is placed and shaped in the prepared cavity, where it rapidly hardens into a solid filling.

Gold fillings: Gold Fillings are made to order in a laboratory and then cemented into place. Gold inlays are well tolerated by gum tissues, and may last more than 20 years. For these reasons, many authorities consider gold the best filling material. However, it is often the most expensive choice and requires multiple visits.

Composite (plastic) resins: Dental composites, commonly described to patients as "white fillings", are a group of restorative materials used in dentistry. They can be used in direct restorations to fill in the cavities created by dental caries and trauma, minor buildup for restoring tooth wear (non-carious tooth surface loss) and filling in small gaps between teeth (labial veneer). Dental composites are also used as indirect restoration to make crowns and inlays in the laboratory. These materials are similar to those used in direct fillings and are tooth-colored. 

Porcelain fillings: Porcelain fillings are crafted from a specially formulated dental ceramic material. They are also used as inlays, onlays, and aesthetic veneers. Porcelain fillings are the strongest, most durable, and natural looking option available for tooth restoration today. The porcelain material used in porcelain fillings is a specially formulated dental material, which is stronger than natural tooth enamel. Through strong chemical bonding between tooth surface and porcelain surface, all the vertical chewing force is optimally distributed to the root of the tooth.