All circling roots around the edge of the root-ball, or flattened sideways roots at the bottom, should be cut off at time of transplanting, whether the plant has been in the pot too long or not, otherwise, it can be as though the plant was never removed from the pot. Plants that were not in the pot too long, can become "pot-bound" years after being removed from the pot, if the circling roots were left intact.
If the plant was in the pot way too long, the root pruning has to be severe, the branches need to be pruned equally hard, or many of the leaves removed, and the plant should be potted in a slightly larger container and should be placed in partial shade, out of strong wind, to be babied back to health. Putting a clear plastic bag over the plant to provide a mini-greenhouse for 2-4 weeks can also be very helpful.