In previous times a fake tooth was easily removable, and if it was different than the other teeth, such as being made of gold, the lady might be embarrassed and take it out on Shabbos.

Chapter 303 Section 13

A lady cannot go out with a torn shoe as she may become embarrassed, take them off, and carry them.

Chapter 303 Section 14

A young girl cannot go out with the hair piece of an elderly lady or the opposite, as people might make fun and she might come to carrying. [This is not a shaitel but rather a band of hair used to hold the rest of the hair.]