Final answer:
Teeth are marked during dental procedures for identifying and treating areas that require intervention, whether it's for fillings, decay removal, or other dental treatments.
Step-by-step explanation:
True. Teeth are typically "marked" during dental procedures when identifying areas that require treatment. This can involve different phases, as shown by various sources. Initially, x-ray images, such as the ones from Dmitry G, Wikimedia Commons, can reveal fillings and other dental works previously done or highlight areas where decay is present, requiring intervention. Additionally, in the course of dental procedures like cavity filling, tools such as hard-bits, and half-cone burrs are used to prepare the tooth, effectively "marking" it for treatment. This preparation might be for the removal of dental calculus or for the treatment of caries as described in the excerpt where McTeague fills Trina's cavity with gold after excavating the decay.