General risks of dental check-ups
How dental check-ups can damage the health of your teeth
Damage via dental examinations with probing
Make no mistake, even a "harmless" dental checkup can cause possibly irreparable damage to your enamel when the dentist uses a sharp metal probe/hook to scrape and poke into your teeth. Tiny carious lesions are cracked open through this check-up and a hole can form.
Dental researcher Dr. Gerard Judd advises, "Don't let a dentist poke your teeth with sharp probes. It will make holes in your teeth making cavities. Don't let a dentist poke with sharp probes under the gumline. It will make holes that will catch food and cause gum infection."
If you wish your teeth to be examined, I would insist that s/he uses no metal instruments. There are other non-invasive ways to check for softened enamel (such as dyes).
Subsequent damage from false diagnoses and treatment advice
Sadly, it is an established fact that the diagnosis and treatment advice you may be given at a dentist's (in fact, at any doctor's) office is not necessarily correct and for your good but may be based on ulterior (financial) motives and/or simple incompetence (details see 10 dentists - 10 diagnoses).