Meaning: Cleaning your teeth twice a day can help you avoid needing to go to the dentist for treatment.
Choice of Words: "Brushing" is the act of cleaning one's teeth using a toothbrush and toothpaste. "Twice" means two times. "Day" refers to a 24-hour period. "Keeps" means to maintain or preserve something. "Dentist" is a person who is qualified to examine and treat teeth and gums. "Away" means to create distance from the current location or to move from the speaker.