Do you brush your teeth regularly? (Every second Saturday in months that end in '-une' counts as "regularly"...)
Do you brush your teeth every day?
How many times do you brush your teeth per day?
Do you floss less often, as often or more often than you brush?
Do you clean your tongue?
What do you clean your teeth with?
What brand/model of toothbrush do you use?
How often do you change toothbrushes or brush heads?
How often do you see a dentist?