As others have said, it is important to go for regular dental check-ups because dentists examine you for many things that you cannot necessarily see or be aware of, and it’s not just your teeth, it’s your mouth and jaw in general.
My mother died, aged 47 years old, of a very rare but very aggressive cancer of the mouth. This began in her gums, and was picked up (too late, sadly), by her dentist. Less than a year after the cancer was detected, she was dead, after having had a large portion of her lower jaw bone and face removed. She took care of her teeth, never had any obvious problems with them, and could have easily thought that she didn’t to see the dentist because of her good dental health.
I would therefore urge people to keep up with regular dental examinations, and get past the believe that dentists are just there to check for cavities. Whilst these sorts of illnesses can be horrific, cancers like this are very unusual, and if you are going to develop cancer, going to the dentist may not prevent this. However, it will mean that any abnormalities are detected early, giving you the best prognosis.