What an unconvincing argument! Sure, the physical shape of our mouth and teeth can change, emotions can temporarily give us different expressions, and our environment can shape our smiles -- but that's actually why smiles remain the same! Our physical, emotional, and environmental experiences are such a significant part of our lives that they create a unique and timeless smile that stays with us even as we age. UrRong; Nikhil's original essay was right all along - our smiles are here to stay!