I have 9 U-aligner. I was supposed to have IPR in 4 places as prescribed at Align Technologies. However, my dentist forgot to do it. After wearing my 7th U-aligner for 4 weeks (as advised by the dentist as I have difficult wearing the 8th), I have been wearing my 8th U-aligner for 9 weeks now as I am having difficulties wearing my 9 U-aligners.Is this because my dentist forgot about the IPR? Can I change dentist at this stage? Does it cost more if I order more aligners? What should I do now? Thank you for your advice!