Infected? Unpossible - I brush every day!

Almost every day I see people with infected teeth. How do the bacteria get in there?

We all have bacteria thoughout our bodies, but only in limited numbers and they get eliminated by our immune system.

So why not inside a tooth? The teeth that get infected have a reduced blood supply because the root canals have become narrower due to secondary dentine build up.

Long-story-short brushing and flossing won't stop teeth becoming infected.