False teeth - Yechaveh Daat 1:8

Do false teeth need to be kashered for Pesach? As strange as this question sounds, since they are not part of the body per se, and thus can be considered a utensil, they should be given the same scrutiny as any other utensil used for food.

Rav Yosef comes up with two easy reasons to say that false teeth need only to be cleaned, but not actually kashered. First, since food only absorbs via heat that reaches the level of yad soledet, and since yad soledet can be estimated as being a temperature at which one would put a food in one's mouth, then be definition one does not generally put food that hot on such teeth, and thus they are unlikely to have absorbed chametz. Second, since people tend to eat with utensils, that means that the food only got to their mouths via a kli sheni, which does not possess the requisite heat to present a problem.

Finally, Rav Yosef notes that he spoke with a leading dentist, who mentioned that false teeth certainly do not absorb any food, since they are specifically made out of a material that does not absorb, since if it did that would ultimately destroy the teeth.