That's a good point Matt, but I feel it is probably a moot one, I think these Dentists are likely to appeal to people who can't get on an NHS dentist register in their local area, or who don't attend a dentist regularly, and therefore don't really have a patient history.
This was brought home to me when I attended an Out of Hours dentist a while back. Because this service is open to everybody, I was pretty much the only person there who when they gave their details in at reception, visited their dentist regularly. Most people attending didn't use the dentist, and just used the emergency dentist when needed. I feel our inflatable Hungarian drill-wielding friends may find the same kind of clientèle.
I must admit, the health and safety issue does worry me, as does the privacy aspect. You feel pretty vulnerable at a dentist with your mouth wide open and a variety of metal implements rammed inside it, you wouldn't need two lost old dears wandering through with their shopping and yapping dogs in tow, asking their way to the bus stop as you are having root canal, would you?
Ian