Question 1: My new teeth become stained?

The temporary bridge is more likely to stain, for the materials used, less valuable.
The permanent bridge is realized with a more solid material and the coloring is less occurs. Note that this varies from person to person and depending on the food eaten. Many foods and drinks contain pigments, (wine, tea, coffee, sauces, etc.), which have the proper attention.
The dental hygienist will clean and polish the teeth by removing the stain.