A dental prosthesis is a fixed or removable appliance used to replace one or more lost or missing natural teeth or part of a tooth by any type of work made outside the mouth. It is used to replace the function of the original teeth.
Here are some examples:
Fixed prosthesis: crowns, onlays, porcelain veneers, and bridges are examples of fixed prosthesis. They can be supported by natural teeth or by implants and cannot be removed by the patient.
Removable prosthesis: full or partial dentures are the main examples. They are not permanently fixed but only supported by the oral mucosa and adjacent teeth or implants. They are much less comfortable then fixed prosthesis but in some situations, may be a good treatment alternative such as a short term temporary solution during extensive implant and bone grafting treatment.