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Elements of Smile Design

I love music. I can tell if it sounds pleasing to the ear or if it sounds wrong. I even play the bass guitar, but I don’t consider myself a musician. I can’t write music and if it sounds wrong, I wouldn’t know what to do to fix it. The best musician can read and write music and can make songs better by adding the right notes.

I love to eat. I enjoy good food, especially great sushi. I can cook a little in the kitchen and pull off a decent meal. But, I’m not a chef. A chef can create masterpieces in the kitchen, tasting sauce from a pot using a wooden spoon and know exactly what to add. That is what we expect from a great chef.

I love smiles. But, if all I could do was look at a smile and tell whether or not it looks good, I wouldn’t be a very good cosmetic dentist. A great cosmetic dentist can break down all the subtle nuances of a smile to the basic elements.

A great cosmetic dentist can not only point out why a smile looks fantastic or less than perfect, but has the knowledge to know exactly what to add or take away and the skill to do it. This is what we should expect from a great cosmetic dentist.

Elements of smile design are the objective principles we use to evaluate a smile. There are the objective principles, then there are the subjectivities of style.

Many patients that I see for consults ask similar questions. I will discuss elements of smile design using pictures of Jenna, a patient who happens to be an NFL Cheerleader for the Jacksonville Jaguars and has a beautiful youthful smile.

Incisal Embrasures

One question I received recently was regarding the shapes of the inverted “V” spaces between the biting edges of the teeth. These spaces are called incisal embrasures. The right lateral picture of her smile below shows these areas in more detail.

The incisal embrasures are often overlooked as one of the most important elements when designing a smile. Many of the characteristics we give a smile are embedded in the shapes and depths of these little triangular negative spaces. In fact, I can take a smile that looks completely worn down, aged, fake or just plain wrong, and by only changing the contours of the incisal embrasures, make it a beautiful smile. The percentages reflect a good starting point for depths of incisal embrasures relative to the length of the tooth contacts. The depth of incisal embrasure between the two front teeth is usually 10%-20% of the contact area of the two teeth. The depth of the incisal embrasure between the next two teeth is usually a bit deeper and it continues going a little deeper as the teeth move more toward the back teeth. This is a characteristic of natural teeth. Often patients have the perception that those incisal embrasures should be very shallow and that look is more flattering. In “Hollywood” styled smiles, the embrasures are more shallow and if it is overdone, can look very fake. This is an old interpretation of a “Hollywood” smile, when teeth that look like a movie stars where all the same shapes. The new interpretation of “Hollywood” is more about character in the smile and unique looks. Be sure to compromise and have some incisal embrasure between the teeth to avoid an overly fake looking smile. Men have shallower incisal embrasures than women. A woman who wants small and shallow incisal embrasures needs to be warned that it is a masculine trait. Also, as the teeth come in when we are children, those incisal embrasures are the deepest, and as we get older, we wear down the incisal edges of our front teeth making the embrasures smaller and shallower. So, it is also a more mature looking smile as opposed to a more youthful smile. My youthful female smiles have the deepest embrasures and can lend themselves to other characteristics like sexy and exotic. With the flick of a wrist and a thin diamond disk, I can take an old looking smile and contour it into a youthful or sexy grin. Here is a summary of the looks.

Shallow Incisal EmbrasuresDeep Incisal Embrasures
Old “Hollywood”Exotic
New “Hollywood”

Tooth Shape

A woman was in my office today for a cosmetic consultation. She did not like the look of her old veneers. We were discussing the general shapes of the veneers and how they did not look like teeth. Teeth are made up of line angles, marked in green, that create reflective and deflective zones.

I can completely change not only the shape of a tooth by changing the line angles, but also the rotation, axial inclination and proportions of the tooth. I can make a skinny tooth look wide and a crooked tooth look straight by manipulation of the line angles. Being able to understand the line angles and have the skill to manipulate the line angles to create different tooth shapes is one of the most important skills a cosmetic dentist can possess. Having this ability gives the dentist the power to change the looks of temporary veneers on the fly, letting patients experience different looks before the porcelain veneers are fabricated by the lab. It enables a dentist to change the look of natural teeth or old crowns and veneers by contouring them into different shapes. Being able to see the line angles of teeth allows the dentist to see what is wrong with each tooth in the smile and the knowledge of what it would take to correct it.

More mature and masculine smiles have line angles that are straighter creating more rectangular shaped teeth. More feminine teeth have more rounded and fuller line angles. The curvyness of the line angles can create sexier looks in the smile. Traditional “Hollywood” smiles have less rounded line angles. Think about the most common remark about a person’s teeth that has bad veneers, “They look like Chicklets.” rectangular pieces of white chewing gum. The line angles of a piece of Chicklet gum are very straight. The height of contour of a Chicklet is also toward the middle of the gum. That creates a bulky look. People are thankfully moving away from desiring that classic white straight “Hollywood” look and moving toward more rounded line angles that set up more character and personality in the smile. Notice the roundness if the line angles in Jenna’s smile. They are indicative of a youthful and sexy looking central incisor. The shape of the lateral creates a flirtatious look and the axial inclination of the canines in relationship to the laterals forms the depth of incisal embrasure that creates an exotic look.

Tooth Display

As people age they show less and less teeth when their lips are at rest and when they smile. The front teeth wear down getting shorter and at the same time, gravity is pulling on the upper lip making it hang lower over the teeth. When the smile is older, no teeth show with the lips are at rest (Repose) and less tooth shows when people smile.

In Jenna’s youthful smile, more than 3 mm of incisal edge tooth display with her lips at rest. Other factors can influence the amount of teeth that people show during repose and full smile. A common influence are dermal fillers placed in the upper lip. If the fillers are placed without taking into account the effect on the overall smile, the result can be prematurely aging the smile. Rather than making the patient look more beautiful and youthful, it ages the face by years. If you do not show much teeth at full smile, then it may be a good option to lengthen your teeth. Other factors go into whether or not a patient is a good candidate for longer teeth. All the teeth work together in the mouth as a system with the muscles of mastication and the Temporomandibular Joint (TMJ). It is necessary for the cosmetic dentist to look at all the parts of the system and not arbitrarily lengthen the front teeth or else there may be a higher tendency for complications.

Reflective vs. Deflective

If you have whitened your teeth and still thing your smile is still too dark, there may be a possibility that your teeth are deflective. Deflective teeth always look smaller and darker than reflective teeth. The front teeth should be standing straight up and down when viewed from the profile. Often times, front teeth are deflective, meaning that the edges are tipped in toward the inside of the mouth. When this occurs, the light bounces off the teeth and deflects away from the viewer creating a darker looking tooth.

When the teeth are standing straight up and down, the light bounces off the front of the teeth and back to the viewer, creating a lighter looking tooth. How to correct it? Use porcelain veneers to upright the teeth. Teeth that are tipped back lingually toward the mouth require minimal or no preparation for veneers, since the goal is to bring the teeth out. Another option is traditional orthodontics or Invisalign. These cases do great with Invisalign and be set up to correct other conditions like crowding or spacing at the same time. If you like the idea of minimal or no preparation veneers, consider moving your teeth with Invisalign into a lingually tipped position, before getting porcelain veneers.

Do you find this information helpful? Let me know, if there are any specific questions I can answer! Leave me a comment.

If you have specific questions about smile design or cosmetic dentistry fill out a contact form with your questions, and I will do my best to have the answer!