Post-Invisalign Gap. Is This Normal Or Should I Seek a Second Opinion?

As mentioned previously, spaces sometimes result when crowded teeth are uncrowded as no tissue is present to fill the space.  This can usually be anticipated and discussed so there are no surprises at the end of care.  There are several options that can be discussed to correct this problem including bonding, refinement with inter proximal reduction to pull the teeth closer together, or possibly veneers in problem areas.  Discuss these options with your dentist as refinement by Invisalign has to occur soon after Invisalign is completed.   Best of Luck.  It can work out.

While there is some merit to each of the posts below, it is important to note that the inherent shape of the teeth may be responsible for the spaces.  Often times, the width of the teeth at the biting surface of the teeth is larger than that at the gum.  Therefore, even if the roots are moved and the teeth are in fact parallel/straight, unless there is gum coverage, you will expect these "spaces".

Keep in mind that the teeth themselves are actually touching each other, so there is no true "orthodontic space".   Therefore, if the gums do not grow back (which they may or may not, depending on a variety of periodontal criteria) you may need to have the teeth reshaped interproximally (IPR).

Hope this helps!