What type of dental structure is generally not polished?

Teeth with extensive decay or non-restorable areas should not be polished because polishing involves the use of abrasive materials to smooth and shine the surface of the teeth. This process is intended for healthy tooth structures or those with minor imperfections, as it enhances their appearance without causing harm. When decay is present, particularly extensive decay, the tooth structure is already compromised, which means that polishing could potentially exacerbate the condition rather than improve it.

Furthermore, polishing may not effectively remove the decay itself and could possibly cause discomfort or pain by irritating the already vulnerable area. In cases where the tooth is non-restorable, it would be both clinically inappropriate and unethical to attempt to polish the surface as it could lead to further complications. Maintaining the integrity of the tooth and promoting overall dental health is the priority, making this option the correct choice in the context of what should not be polished.