After they hear this people usually ask why we need our own dentist, or they roll their eyes about supposed extravagence like the well-known free meals at work and so on. Actually, I'm surprised more companies of their size don't have their own dentist. Just do the math (I had to do some math in my interview also): with 3000 employees visiting the dentist twice a year on weekdays, that's 24 patients a day, which is more than a full load. Do you want those people staying at work or leaving the office for several hours each time? On top of that, the after-hours service is key because people here are night owls, and a dental emergency could leave someone unable to work for quite some time during a key product release.
It seemed logical enough (why shouldn't big companies provide on-site dental service to their staff?), and quite a few people fell for it. But when curious bloggers asked Google directly about their dentist, Google denied all knowledge of such a person, revealing it to be a hoax. Since then the GoogleTooth blog has disappeared, though it's still in the Google cache. And below are a few pictures of the office of Google's dentist.