Soak a non-abrasive sponge in the baking soda/ammonia solution. Dip the sponge in the solution, scrub, and repeat until you're satisfied. Rinse well. After rinsing, wipe thoroughly with a clean rag or the baking soda will leave a white film behind.
Acrylic is easier to clean, but doesn't leave a smooth surface. Enamel is smoother, and will generally last longer, but is hard to clean up if you want to change...
The loss of tooth enamel can lead to discoloration of the teeth and to sensitivity. In order to fix this, you should visit a dental professional, who can give you...