Which of the following should be avoided when polishing teeth?

Polishing newly erupted teeth should be avoided because they are still developing and can be more susceptible to damage. The enamel on these teeth is not fully matured, making them softer and more vulnerable to abrasion from the polishing materials. This can lead to unnecessary wear on the enamel, increasing the risk of sensitivity and future dental issues. It's important to handle newly erupted teeth with care to promote their proper development and protect their integrity.

In contrast, while stained teeth, teeth with cavities, and teeth that have been whitened present their own considerations during dental care, the caution with polishing newly erupted teeth is particularly critical due to their developmental stage. Proper protocols should always be followed to ensure the health and longevity of teeth at different stages of eruption.