It’s like cleaning a fish tank: you can’t clean it just by rinsing it with water. There is biofilm that needs to be scrubbed off.
First, we don’t need to kill off normal bacterial flora in our mouth. We just want to disrupt the biofilm to prevent tooth decay and gum disease.
Second, mouthwashes do not penetrate the biofilm. You need mechanical action that is done with a toothbrush. Use a soft brush with high-density bristles. For interdental space, use interdental brushes.
When does mouthwash actually help?
Putting highly marketed daily mouthwashes aside, there are specific solutions that help people with certain conditions, for example implants, before and after surgery, and gum periodontal diseases that need additional chemical plaque control. In those cases, the use of medical mouthwashes should be limited and prescribed by your dentist.