Sealant Problems - from Childhood to Adulthood

Here is another story, this one from a friend of mine:

My story: I received my first set of sealants when I was young, probably 6 or 8years old. They seemed to do their job for a while, but when I was 16 or so, my dentist decided they needed to be replaced; I have no idea if that's true. He must have done a pretty poor job, because when I got a check up this past summer (at age 23), the dentist found five cavities, all under my molar sealants.

What's worse, he had to use a special laser to detect them, because the teeth looked perfectly healthy on the outside; the decay was entirely under the sealants. One was so bad that the dentist was worried I would need a root canal (which, thankfully, I didn't) because it got so close to the root. Let me be clear about what happened here: I did not have any cavities except underneath the failed sealants where I was unable to clean. If my dentist hadn't caught the decay with the laser when he did, I could very easily have lost several teeth.

- Andrew in CA