A collection of several sets of false teeth.  The pink gums are made from vulcanized rubber and the teeth are made from porcelain.  The metal plates are likely made of aluminum.  In the mid 1800s, the invention of the vulcanization process made producing durable rubber goods more affordable.  This made dentures cheaper to make and therefore more popular.  Colouring the rubber weakened the denture, so additional porcelain was added to better match the light pink colour of natural gums.