Upper two front teeth should be wider and longer than the
teeth next to them, and about the same length or longer than
the "eye" (or "canine") teeth.
When the lips relax a bit of the centrals still shows,
especially in a young smile. Shortened upper centrals give a
worn and therefore older appearance.
The edges of the upper teeth follow the curvature of the
lower lip. Teeth that are too level or centrals that are
shorter result in a "reverse smile line" which looks aged.
