2. Relative Dental Proportions
The concept behind relative dental proportions is the belief that there is an ideal set of proportions, not only in dentistry, but in nature as a whole. When these ‘golden proportions’ occur, they are found to be naturally and universally pleasing. Applying them to dentistry, the width of the front two teeth together should be double that of the height of these two teeth. The width of the two front teeth, if the proportions are to be considered ideal, should also be the same as the width of the first three teeth to either side of the midline. How closely a patient meets these ideal proportions determines their score for this principle of smile design in the mDAI.
There has been considerable debate as to the validity of these ‘golden proportions’ in the field of dentistry. The ‘golden proportion’ was usually judged using three teeth to each side of the midline. There is however, a compromise position. As a profession it is agreed that the front two teeth should be viewed as a single unit, and as the ideal width to height proportion is 80%, when we look at front two teeth we see that they have a 160% width to height ratio, which is the ‘golden proportion.’ Therefore, there are three areas where the Golden proportion can be applied – to the front two teeth, and the three teeth to either side of the midline. The measurement of these should all be a 1.6 ratio.