Kinda random thought, but what if you went to the dentist just expecting a regular cleaning, and suddenly they're talking about how your gums could mean you have some other serious health issue? Like heart disease or diabetes or something...would you freak out or just shrug it off as paranoia?
Honestly, I'd take it seriously but wouldn't panic right away. Dentists do sometimes spot early signs of other health issues—happened to my uncle once. He went in for a routine cleaning, and the dentist noticed his gums were inflamed and bleeding more than usual. Suggested he see his regular doctor, and turns out he had early-stage diabetes. Wasn't thrilled about the extra doctor's visit (or the bills...), but catching it early saved him from bigger problems down the road.
So yeah, if your dentist mentions something like that, it's probably worth checking out with your regular doc just to be safe. Better to spend a little now than face bigger medical expenses later on.