Dental Esthetics: Tooth proportion
What are the factors in evaluating a beautiful smile?
There are many factors when someone smiles and you think “She has a great smile!” These include symmetry, spaces, color of teeth, shape of teeth; teeth in relation to lips, face ,shape of head, and other facial features; and the proportion of the size of the tooth and its relation to the other teeth. These evaluations are highly subjective although professionals seek to break down the different factors so that patients can have their smile improved yet still look natural.
THE GOLDEN RATIO
One evaluation is using the GOLDEN RATIO. According to Wikipedia, the number is 1.618…. which was developed as a mathematical formula in the time of the Greeks Pythagoras and Euclid. Researchers note that the way stems come off of branches follows this ratio. The Egyptians built the pyramids very closely to this ratio! When evaluating teeth, dentists look at the width of the front teeth as viewed from an observer. According to Dr. Eddy Levin of the UK, making cosmetic and orthodontic corrections according to the Golden Ratio gives a very pleasing improvement. On the other hand, many are of the opinion that this guideline gives a low rate of satisfactory results. An article in The Journal of Esthetic and Restorative Dentistry claims that this ratio is in fact not valid. Controversy of this sort is no stranger to dentistry.
What will your dentist do?
For the dental practitioner there is no substitute for good eyes and common sense. Patients frequently want the incisal edges (the edges of the front teeth) to be in a flat line. This is not esthetic and frequently indicates that the patient has been grinding their teeth and has a problem that needs correction before they wear their teeth down. In general, the lateral incisors should be a little shorter than the teeth on either side. Also, when one smiles, their posterior teeth should appear to rise with the lip line. If the teeth seem to drop down, that is not esthetic.
Correction of esthetic proportion imperfections vary. Veneers and crowns can be used to get the length correct. Some patients have an imperfection of the gum, either too much covering the crown or too little showing the root, and a periodontist can help with this. Orthodontics including Invisalign can place the teeth in a proper place which gives a more pleasing proportion. I like to do an esthetic workup including study models and photos before embarking and any extensive makeover.