You’ve probably heard this dental advice before: Brush your teeth twice a day. Remember to floss. Get those pearly whites to the dentist twice a year. But are they true? And why do we have to do these things? We asked dental hygiene professionals to answer five basic questions about how to care for your teeth and keep them healthy. Here’s what they had to say. 1. How often should I really brush my teeth? Photo Illustration by Becky Harlan/NPR Photo Illustration by Becky Harlan/NPR You should brush your teeth twice a day for two minutes a day, according to the American Dental Association. But teeth maintenance is more than…