Dental restorations are also known as dental fillings. Fillings restore missing tooth structure that is caused by dental cavities or external trauma, allowing the tooth to continue to function as it is intended. Fillings are either direct and indirect; direct fillings are sculpted onto the surface of the tooth itself, while indirect fillings are crafted in a lab, based on a mold of the patient’s teeth, and then cemented into place once they are made.
Before a tooth can be restored with a filling, it must first be prepared. Preparing the tooth requires that the dentist drill or otherwise cut the damaged area out of the tooth, removing decayed or significantly weakened portions of the tooth. Once the tooth is prepared, the filling is placed. If an indirect filling is being crafted, the dentist may place a temporary filling on the prepared tooth to protect it while the permanent filling is made. Dental fillings may be made from a variety of materials; dentists choose the proper material based on the location of the filling, the extent of damage, and the needs and budget of the patient. Materials include gold, metal amalgam, composite resin, and porcelain. Restorations may fill in the damaged area, or they may be designed to fit over the damaged tooth.
Direct fillings are made of a sculptable, soft material that is sculpted in layers onto the prepared tooth and then hardened, often with ultraviolet light. These common dental fillings can be placed relatively quickly, in a single office visit, and can be made from a variety of materials based on the location of the tooth and the extent of decay that is to be repaired. Indirect fillings include inlays, onlays, dental crowns and bridges, and veneers. These indirect fillings are made in a lab, based on impressions of the prepared tooth or teeth. While they are being fabricated, the patient will have a temporary filling placed to protect the prepared tooth. Once completed, the indirect restoration is then bonded to the tooth with dental cement. The most commonly used materials for indirect fillings are gold and porcelain. Dentures are also often considered a type of indirect restoration, since they restore the function and appearance of missing teeth.
Materials used to make both direct and indirect restorations vary widely in price and in their characteristics and preferred used. Composite resins and metal amalgams are the primary choices for direct restorations. Composite resin may be preferable for teeth that are located in the front of the mouth, as it can be tinted to match the natural teeth, whereas metal amalgams are metallic in color. Metal amalgams are more durable than composite resins, which makes them a better choice for the load-bearing needs of the rear molars. Composite resin restorations have an average life span of about 8 years, while metal amalgams can be expected to last as long as 10 to 15 years. Direct fillings are recommended for smaller areas of decay. Indirect fillings are preferable for larger areas of decay. Porcelain inlays, onlays, and crowns are preferable for the visible teeth, again because the color can be tinted and polished to match the natural teeth. Gold restorations are recommended for the molars, as these are the strongest and most durable materials that indirect fillings can be made of; however, gold restorations are also among the most expensive types available. Dental researchers regularly develop innovative materials, and the field of dental restoration is constantly developing.