I had figured they'd simply become more common over the last ten years or so -- I never remember encountering them in the 80s or early 90s, but I have always had dams used in the last few years. However, I've had a number of different dentists over the years and my current dental office is very "up to date" with everything (it seems like every time I have a cleaning, they have new hygiene recommendations based on the most recent dental conference they went to) so that might have something to do with it too.

The good thing about the dam (for me as a patient) is that it keeps all of the chemicals from coming into contact with my mouth, but the bad thing is that sometimes I kind of feel like I'm drowning. Usually when the dam is in, they either have the suction thing left permanently in the corner of your mouth while they're working, or the dental assistant suctions you periodically. But it's hard to signal when you need it, because they can't see that you need it and you can't talk at all. (But I've also had that problem with regular dental work, so maybe I've just had inattentive dentists ...)

The other problem with it is that the metal frame that holds the dam in place is kind of painful, and my jaws are often sore afterwards because you can't really shift your jaw or half-close your mouth to rest the muscles like you can otherwise.