I have a lot of friends who have a hard time brushing their teeth due to sensory or motor issues, so this might be a neat (if somewhat more expensive) alternative:

Picture of the Rolly

[picture of the Rolly: a small circular gummy thing with bristles around the edges]

You chew on these little gummy discs as if they were pieces of gum, then spit themn into the trash. Cool!

(Source: Gizmodo)