It's also where the bacteria that we get from eating food resides specifically actinobacteria/actinomycetes. The dentist offices are a breading ground for this stuff and their sterilization methods will not kill it. They did endoscopy procedures on people with whipple's disease soaked the scope in chlorahexadine for 15-20 mins and the bacteria was still found on it. So you can only imagine how many dentist offices and how much hospital equipment is tainted with this stuff and their completely unaware of it. Makes you never want to eat out again in a restaurant.