This is true.
A well known heart surgeon examined the hearts of many patients and found in 98-99% of them with heart disease, they had bacteriafrom the mouth there causing problems.
Root canals being one of the primary ways harmful mouth bacteria travel down into that area of the body.
Bttt
I once had an abcess and needed a root canal. My dentist put me on antibiotics before he did the root canal and continued for maybe two weeks afterward. I think he did say it was to prevent heart trouble.
Of course bad diet, including a lot of white sugar and starch is hard on the mouth, and that moves into obesity, diabetes, and heart trouble. Do schools today even have health classes?