Perhaps off topic, but brushing my teeth before bed is such an ingrained habit for me that it actually takes a force of will to choose not to brush them. I.e. brushing is actually easier than not brushing.
Agreed. I have trouble falling asleep without a fresh-just-brushed-my-teeth feeling. An annoying habit in the beginning can become a necessity later on.
Not only that it triggers your brain to start getting sleepy.