Do not ask for persons with "Lost all teeth" in 6b.
7a. (Now I am going to ask about some things that people may be doing to take care of their teeth.)
What does -- use when [he/she] brushes [his/her] teeth -- toothpastes, tooth powder, or something else?
1  Toothpaste (7b)
8  Other (Specify) ____ (NP)