An employee told me today about his grandmother, who never took care of her teeth and had lost most of them, and because of the disease in her mouth and gums, she developed a heart aneurysm and died. This is one of the reasons he feels so committed to working here, convincing people to go to a dentist and helping them to find one. This is very personal for him.
What people are gradually learning is that gum disease can put bacteria into your bloodstream, and often this bacteria is the same bacteria that causes the buildup of arterial plaque. (Odd that it forms plaque in your mouth and your arteries--or maybe it isn't so odd.) It has now been shown to possibly cause a stroke.
It doesn't seem that neglecting your teeth could be fatal, but it is possible. The gums lead directly to the bloodstream--it's why heart patients put nitroglycerin under their tongue when they feel a heart attack coming on. The body absorbs it very quickly. The same is true when you don't control the bacteria in your mouth.
Crazy stuff, but true. Being afraid of the dentist is potentially life-threatening.