Quick ?? are you talking about a space maintainer, or a space regainer? seems like people on here are talking about 2 different things... a space MAINTAINER shouldn't hurt at all.... it is put in after a baby tooth has been pulled but the adult tooth isn't nearly ready to come in, so that is placed in to hold the space open so the teeth don't come together. A space REGAINER is usually used by an orthodontist to open up a space between teeth that has closed up and needs to open again... the Regainer is usually slightly painful (it's just like braces.. moving teeth always hurt a little) while a space maintainer shouldn't hurt, just takes a little adjusting to get used to that new piece of metal in their mouth..... should be 2 appointments for the maintainer-- 1 for the impression and 1 to cement it to the teeth.. neither appointment should take very long and there is no numbing involved... HTH