I lead a pretty healthy lifestyle. A longevity quiz I took around 2000 showed that tooth flossing was the single thing I could to do to extend my lifespan.
But, I was lazy and couldn't understand the connection.

The theory was that the bacteria that infect the gums and cause gingivitis and periodontis also travel to blood vessels elsewhere in the body where they cause blood vessel inflammation and damage; tiny blood clots, heart attack and stroke may follow. Supporting this idea is the finding of remnants of oral bacteria within atherosclerotic blood vessels far from the mouth. Then again, antibiotic treatment has not proven effective at reducing cardiovascular risk.

In 2015 I needed a stent because of arteriosclerosis.
In 2016 and 2018 I needed a tooth pulled because of an abscess, so I started looking at this.

The bottom line is, There is reason to suspect a connection, but no hard evicence to prove it.
I'm going to do a better job of flossing;
There is no evidence that too much flossing can damage your gums. :-)

Gum disease and the connection to heart disease - Harvard Health - 2018
'A recent study is among the largest to look at this question. Researchers analyzed data from nearly a million people who experienced more than 65,000 cardiovascular events (including heart attack) and found that:

• After accounting for age, there was a moderate correlation between tooth loss (a measure of poor oral health) and coronary heart disease.
• When smoking status was considered, the connection between tooth loss and cardiovascular disease largely disappeared."

Use of floss/interdental brushes is associated with lower risk for new cardiovascular events among patients with coronary heart disease (CHD)- Reichert - 2015 - Journal of Periodontal Research - Wiley Online Library
"These findings suggest that flossing and brushing of interdental spaces might reduce the risk for new cardiovascular events among patients with CHD. The hypothesis that interdental cleaning per se reduces the risk of new cardiovascular events should be examined in an interventional study."

Periodontal Disease and Heart Health | WebMD 2015
"Some research suggests that the more bacteria you have from gum-disease, the thicker your carotid arteries may be. If they're too thick, blood can't flow to your brain. That can cause a stroke.
...
"For the most part, the data is circumstantial. It's hard to prove cause and effect," says Thomas Boyden, Jr., MD. He's the medical director of preventive cardiology at Spectrum Health Medical Group Cardiovascular Services in Grand Rapids, MI. "
"People with bad periodontal disease tend to have bad health habits in general," Boyden says. "They aren't taking care of themselves. Many are smokers."

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