What goes into making a beautiful smile?

This person's smile is as near perfect as you can get.

Symmetry – the teeth on the left-hand side mirror almost exactly the teeth on the right hand side

Facial midline aligns with the dental midline – if a line is drawn through the middle of the face it passes through the line between the upper central incisors

Gum display – the gum margin where her teeth meet the gum is brushed by her upper lip

Incisal edges – a line joining the biting edge of the incisors follows the bow of the lower lip

Fullness – the teeth go right up to the cheeks

“A march of retreating hills” – each tooth can be seen – but after the first one a little bit less of each, like a series of hills retreating to the horizon.

Colour – each tooth is the same colour as all the others


There are a huge number of factors that must be right to make a perfect smile.

When we rehabilitate a patient’s smile, we weigh and balance each factor on an individual basis.

Golden proportion

This is a ratio found in art. It is a sign of pleasing proportion.

The teeth also follow certain proportions, generally this is a vertical rectangle – the width of the upper central incisor should be 80% of its length. On average that means a length of 10 mm and a width of 8 mm.

However, it is not as often found in nature as textbooks would have you believe.

The actual proportions of these teeth are: 1.45/1.0/0.75. Her smile still looks great and really, when it comes down to it, a pleasing smile is as much about symmetry as it is about golden proportion. Facial portions and skin tones also play a significant part in aesthetic decision-making.

There is an art of smile design which cannot be reduced to number proportions.

Superficially this image looks similar, same pose.

The broad strokes are there, midline is in the correct position (although at a slight angle), and the incisal edges follow the bow of the lower lip.

The colour of her teeth is good. The shape of her teeth is good.

When you look at the smile what detracts from perfection is the angulation of the teeth and lack of symmetry between one side of the smile and the other.

Let me explain

Instead of the midline being parallel to the facial midline it is at a slight angulation(canted). The lateral incisor on the right-hand side is pushed out and most of the back teeth, instead of being straight up-and-down, are slanting inwards.

To add insult to injury even the central incisors are not symmetrical. The incisal edge of the left central incisor has a notch on the biting edge.

How would I correct this, if she was my patient?

Clear aligners would resolve quite a lot of the misalignment, which would probably take about six months in total.

I would align the angulation of the midline with the midline of her face, tilt the back teeth out, to be more upright, which would create the space to allow me to tuck the lateral incisor on the right-hand side more into the line of the arch. Easy, with a great result.

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