Brushing teeth too hard can cause gum recession, creating recesses where bacteria can accumulate.

“Also things like using a soft toothbrush, because if you brush too hard, if you take that approach and you're going to brush your teeth really hard, get them really, really clean, yes, you'll scrape off all the biofilm, you'll avoid tartar build up, but you can really cause some tenting of the gum tissue above the teeth and those little recesses back in there where bacteria get in.”