Well I was born in 1960 and have never seen a dentist for a procedure that may cause bleeding without premedicating in my entire life. I think this "preventative" medication is to cover dentists from getting sued if you contract endocardits after treatment. My endocarditis was caused by chronic bronchitis that "festered" and sent bacteria to my arotic valve and my prostate. BTW if you get chronic bacterial prostatitis your prostate may never be the same again. Don't ask me how I know that.
I was "lucky" that I had a picc line put in and was able to go home, go back to work, and function fairlly normally during my IV treatment. I gave myself the once a day dose of Rocephin (ceftriaxone) 2GM daily flushing with saline and heplock before and after. A home health nurse came by once a week to check my vitals, my picc line site, and change the protective dressing.
After that was done I found out I needed to have my aortic valve replaced and my VSD repaired. The infectious disease doc said that my VSD made me more vulnerable to bacteria entering my left ventricle and colonizing on my aortic valve.
Sooo...one of the several reasons I chose a Ross Procedure is that it significantly reduces the chance of contracting endocarditis compared to other prosthetic valves since you have your native pulmonary valve in the aortic position. And regardless of the current guidelines I will take antibiotics before any dental procedure that may cause bleeding or any other invasive procedure. I had my first colonoscopy about 9 months after surgery and they gave me IV gentamycin and IV clindamycin before the procedure. They also gave me some happy juice which was the most important IV I got.
My tummy is pretty tough when it comes to antibiotics so taking a 2GM loading dose of amoxicillin 1hr before dental work and a 1GM dose 4hrs afterwards (that's what I took last time) is no biggie. The only side effect I've ever had from preventative penicillin or amoxicillin is the smell of it when you go to the bathroom.
Long post...short summary...I will follow my cardio's advice or my dentist's advice...whichever is most cautious. If both say I don't need antibiotics I guess I won't take them since I can't write my own prescription.