Yes. You can't reach the bacteria in tight spaces between your teeth and under the gum line with a toothbrush. Aim to floss daily. If you find it hard to handle floss, use an interdental cleaner — such as a dental pick, pre-threaded flosser, tiny brushes that reach between teeth, a water flosser, or wooden or silicone wedge plaque remover. As long as you do a thorough job, it doesn't matter if you brush or floss first.