One of the foundations of an esthetic restoration is gingival position. It is always better to have that discussion with patients before we begin.
I remember all too well having a patient ask me why their new crown was shorter than the tooth next to it and then trying to explain that it was the same size as the tooth before the crown; however, the "gum line is at a different height than the tooth next to it."
That became an excuse rather than an explanation and led to an unhappy patient.
Sometimes, though, our patients get in their own way. This patient is an example. She agreed to orthodontic treatment to align her anterior teeth and then stopped treatment part way through. If you look at her pretreatment image you'll see that the centrals look reasonably straight. Next, look at the preparations and you will see the rotations that are present in the arch.
Not even aggressive tooth preparation can make up for the malposition of her teeth. Even with aggressive esthetic crown lengthening the gingival levels will never be at the same height. Because the boney architecture on the facial surfaces of the centrals cannot be at the same levels – the facial-lingual orientation won't allow it – the only way the gingival heights can be the same is if the teeth are moved into a more normal arch form.
The end result is OK, but it could have been great had she allowed the process to unfold.