Why should we brush our teeth before going to bed?

[tanyajack]

On one team are dental plaque–sticky, colorless film of bacteria–plus foods and drinks that contain sugar or starch (such as milk, bread, cookies, candy, soda, juice, and many others). Whenever we eat or drink something that contains sugar or starch, the bacteria use them to produce acids. These acids begin to eat away at the tooth's hard outer surface, or enamel. On the other team are the minerals in our saliva (such as calcium and phosphate) plus fluoride from toothpaste, water, and other sources. This team helps enamel repair itself by replacing minerals lost during an "acid attack." Our tooth go through this natural process of losing minerals and regaining minerals all day long.

https://www.youtube.com/watch?v=vT-DcI5czIQ