Which statement is true regarding light cured materials?

Light cured materials are designed to set and harden when exposed to a specific wavelength of light emitted from a curing light. This process is facilitated by a photoinitiator present in the material, which activates the polymerization process once the material is illuminated with the appropriate light. This characteristic is particularly beneficial in dentistry, as it allows for precise control over the setting time and enables dental professionals to work efficiently without the need for additional heat or chemical activators.

The other options fail to accurately reflect the properties of light cured materials. For instance, they do not require heat to set, as the curing process is driven by light rather than thermal energy. Additionally, while they can be used for permanent restorations, they are not limited to temporary applications. Lastly, light cured materials are typically designed to be sensitive to specific light wavelengths, meaning they can indeed be affected by external light if it falls within the curing spectrum.