Disagreement with dentist regarding removal of child's space maintainer. Help!?

My 7 y/o had a space maintainer put in last August due to 2 of her teeth being pulled out. The adult teeth technically shouldn't have been in until she was 11-13 y/o. Well, they are now coming in and the one is growing right into the space maintainer band. It also looks as if her front teeth are being pushed out at an angle from the connecting bar. She had her 6mo. check up in June and the dentist said it looked fine and he'll check it again in 6 months. My husband was looking at it tonight and he said he thinks it needs to come out ASAP. The dentist isn't concerned, but we are and want it removed. The dentist is throwing the dental degree stuff at us and insisting he knows what is best in this situation. I know he has to remove it if we insist. What do you do? Do I go with my gut that something is wrong with it or do I take his word and pray nothing screws up her teeth more than it looks like? Sorry for the book and thank you for all answers!