Yes, 2000 mg of amoxicillin should absolutely be taken one hour before a dental visit. Indeed, the dentist should not see you unless you confirm that you have done this. Also, it happens that I had a much-postponed dentist visit this past week after a recommendation from my cardiologist, who thought I was needlessly postponing dental treatment. Our dental clinic had been closed for a time because of the pandemic, and I was very impressed with the way the clinic had been reorganized. I had my temperature taken at the door and had to respond to questions about symptoms and out-of-country travel before I could enter, and patients were kept "socially distant" from each other at all times. I had a broken crown replaced and three cavities filled, and I am very glad that I finally took this step. My aortic valve was replaced in 2005, and it's still going strong!