Taking dummy away from toddler

So after a few months of constantly talking to little one about the dummy fairy taking her dummy away and giving her a present, we had a dentist appointment today where she was quite happy to give it to the dentist. Everything was fine until bedtime when she started to ask for it and then cried. I explained that the dummy fairy has taken it from the dentist now and tomorrow she will be delivering your present. I also got her a small present straight after our dentist appointment but clearly that didn't matter to her. She was super tired so after 20mins of struggle she's managed to fall asleep. I'm now so worried about her waking up at night because she does still wake up a few times, I don't know how I'll get her back down without it. I do still have the dummy and I really don't want to go backwards. Any advice? She's 3 and half so I feel like she's old enough to understand the concept.