Which of the following is a characteristic of indirect restorative materials?

Indirect restorative materials are characterized by the fact that they are fabricated outside of the patient's mouth before they are placed in the dental arch. This process allows for higher precision and better-fitting restorations as these materials are typically crafted in a dental laboratory using advanced techniques and equipment that ensure a more accurate fit compared to direct restorations.

The creation of these materials outside the mouth allows for a variety of options, such as crowns, inlays, and bridges, to be made from materials like porcelain, gold, or composite resin, which can be processed to meet specific aesthetic and functional requirements. Once fabricated, the indirect restoratives are then brought back to the dental office where they are cemented or bonded into place.

In this context, the other options do not correctly describe indirect restorative materials. They are not prepared and placed during a single visit, as this defines direct restorations; they are not always temporary, as many types of indirect restorations are intended for long-term use; and they do indeed require a dental laboratory for their fabrication, distinguishing them from materials that can be applied directly in the mouth.