Jan 13, 2014 Bad Brushing Habits Are you hurting or helping your teeth when you brush? Here are three common mistakes when it comes to brushing and how to avoid them. Not Brushing Long Enough: Brushing for at least two minutes and at least two times a day is the best way to ensure dental health. Not Changing Your Toothbrush: The American Dental Association recommends getting a new brush every three or four months, or even sooner if the bristles look frayed. Skipping Inner Tooth Surfaces: These are the surfaces that your tongue presses against. The plaque you can't see is just as important to remove as the plaque you can see, so make sure to brush thoroughly.