there are several ways to create spaces during your Invisalign treatment:
1) IPR (filing)
2) Buccal expansion (moving your back teeth outwards)
3) Proclination (moving your front teeth out)
4) Distalization (moving your back teeth backwards, usually into the space previously occupied by your wisdom tooth)
Generally my practice is to create space through a combination of several techniques, which means that sometimes we can minimize the amount of filing needed.
If you are really concerned about the amount of filing indicated, do let your dentist know so that he/she is able to offer you other alternatives. But to echo the sentiments of Dr Sylvia & Dr Kelvin, IPR done correctly would be unlikely to cause sensitivity.
Hope this helps!
Kenneth
