In order to remove bacterial plaque from our teeth, we have to see it. This is done with something called a disclosing agent, usually a red dye that stains bacteria. You can buy it at any pharmacy. Apply it with a Q-tip (after you brush and floss). Paint the edge of your gums where it meets the teeth. Move the Q-tip along, up and down, following the gum line. Now rinse and look to see where the stain is. Then brush and floss again. You’ll notice that although brushing removes some of the stain at the direct edge of the gum, it did not get it all BETWEEN the teeth. Only dental floss will get into these areas to remove bacteria. Brushing won’t.
Do this disclosing daily at first until you really know your mouth, and later three times a week. You really won’t know if you’ve effectively removed plaque if you don’t disclose. It’s like trying to lose weight without checking yourself on a scale. You need a guideline - the disclosing solution is it.