Tooth shaping should be easy for a well trained orthodontist to do and also pain free.
Teeth that have worn badly, due to being misplaced, crossed over, etc, will usually look much better when corrected with minute shaping.
Interproximal reduction (IPR)is another type of enamel reduction. Used to remove small amounts between teeth, when an extraction would be too much. I've had this done between most of my lower front teeth. Pain free and great to allow for straightening and movement that doesn't require a tooth to be extracted.