Cast

Casting is a manufacturing process by which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or broken out of the mold to complete the process. Casting materials are usually metals or various cold setting materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods. Casting is a 6000 year old process. The oldest surviving casting is a copper frog from 3200 BC.

In dentistry, casting is a process by which a detailed wax pattern of a dental restoration is converted into alloy or ceramic. The casting process allows the dentist and dental laboratory to custom-make precision restorations for missing or damaged teeth. Casting is complex and takes place largely in commercial dental laboratories. However, dental auxiliaries must understand casting to communicate effectively with the dentist, patients, insurance companies, and the dental laboratory. This chapter provides an overview of casting at an introductory level. Although machining of restorations is a growing alternative to casting, the majority of dental prostheses are still cast using the methods described in this chapter.

Casting is used to fabricate inlays, onlays, crowns, ceramic–alloy crowns, some all-ceramic crowns, partial dentures, implant restorations and frameworks, and occasionally a complete denture. Thus, the casting process plays a large role in dentistry. In dentistry, casting uses a technique called the lost-wax technique. Castable or pressable ceramics have been developed that also use the lost-wax technique to form either the final restoration or a substructure onto which other ceramics are applied.