A horizontal smile line is most attractive. An imaginary horizontal line through both of your pupils and another horizontal line between the tips of your canine teeth should be parallel. Even when these lines are not coincident, the illusion of horizontal alignment should be created.
The most attractive smiles have mid line symmetry. The human eye can easily detect any difference in the size and shape of your front teeth. Creating mid line symmetry produces the perfect looking smile.
The smile line connects the biting edges of your top teeth. The most attractive smiles possess biting edges which gently follow with the curve of the lower lip.
The gingival outline should follow the upper lip and be symmetrical. Only pink triangles should be seen between teeth. The gingivae provide an enhancing frame to your teeth.
The golden proportion phenomenon is present throughout nature. The ratio 1.6:1:0.6 indicates the amount of tooth surface that should be seen when looking directly at a smile. This is the starting point of reconstruction and smile design.
The most attractive smiles possess teeth with a width to height ratio of 0.7:1.
Embrasures are the natural triangular spaces between the tips of the teeth. Attractive smiles embrasures are smallest between the front teeth and increase in size. Feminine smiles have rounded embrasures, whilst masculine embrasures are square