My wife has always taken good care of her teeth, but is in the early stages of dementia. Her mother died of Alzheimers. Her brother has the same problem. Definitely a genetic thing with them.
Perhaps the genetic disorder is an inability to fight that disease.
I know what you mean. In my first post I said my Mom’s memory is beyond excellent, at 95 y.o., and she didn’t take care of her teeth.
OTOH, my FIL was clinically OCD about his teeth, and had Alzheimer’s in his 80s.
Genes.