Ortho and Temp Crowns?

My orthodontist general cosmetic dentist and perio all think its ok for me to remove my ill fitted over contoured perm lower front 23 and 24 crowns and put temp crowns on for the duration of ortho work 1.5 years and then replace with perms. can you really do this safely without cavities and without having them pop off? At first the perio did not recommend though another prostodontist also said it was ok. I guess its the least of the evils. They are talking and letting me know.