I did not know. My knee replacements affect the cleaning of my teeth. You see, up until two years after the replacements possible infection can be expected when teeth are cleaned. I presume open cuts and bleeding which result from the cleaning can create open access to bad bacteria. I was literally sitting in the chair when the dental hygienist interrupted my expectations. She had the dentist prescribe a drug to stave off infection. I had to go, get the drug prescription filled, and return no sooner than one hour later. Meanwhile, I took a liter of milk to be sure the pills did not disturb my stomach. OK, maybe I could have taken less but I didn't want to waste all that good milk. Back in the chair an ultrasound tool loosened up the buildup on my teeth. Then some scrapping and finally the polishing. As I view my mouth, I'm now in much better shape than before, although my tongue finds it a little different feel to the landscape of the inner world of my mouth!!