Genetics play an enormous part in dental hygiene. Some people in my father in laws side never had a cavity in their entire lives - even 85 y/o grandpa (also my 28 year old wife).
I'm 42, and in the no cavity boat. I was always a daily brusher before bed, but that was it. In my early 20's, I took 5 years off from the dentist and when I finally got an appointment, I had a small amount of tartar build up, and that was it.
I've had the same dentist for almost 15 years now and his comment to me every time he looks at my teeth is: "Boring!".
