Issaquah Family Dentistry,Evenings and Saturdays appointments Implants, Cosmetic

There are TEN factors in a smile design.

SMILE LINE

The shape of one’s teeth typically follows one’s Smile Pattern. The convex curve through the six upper anterior teeth should follow the curve of the lower lip.
The smile line is essentially the smile pattern. While there are as many different smiles as there are people, there are generally three basic smile patterns: Commissure smile, Cuspid smile, or Complex smile.

Commissure Smile

67% of the populations have a "Commissure Smile", in which the corners of the mouth are first pulled up and outward followed by the muscles of the upper lips contracting to show the upper teeth.

The Cuspid Smile (Gummy Smile)

31% of the populations have a "Cuspid Smile", where the upper lip muscle are dominant. They contract first thus exposing the canine teeth, and then the corners of the mouth contract secondarily to pull the lips upward and outward.

The Complex Smile

2% of the populations have a "Complex Smile", where all the muscles of the upper lips, the muscles at the corners of the mouth, and the muscles of the lower lips contract at the same time, showing all the upper and lower teeth simultaneously.

The patient is graded on whether their smile line is right for their particular smile pattern. The teeth should mirror the smile pattern of the lips. In other words, the imaginary line created by the teeth should mirror the line of the mouth.

By looking at these three aspects of a smile i.e.: Smile Line, Relative Dental Proportion, Dominance of the Central Incisors, one can objectively describe a patient's smile.

RELATIVE DENTAL PROPORTION

Three measurements must be symmetrical with regard to the top 6 teeth, known as the "social six". Combined width of 2 front teeth should be same length from midpoint to either 3rd tooth cuspid. Front 2 teeth should have combined width to height ratio, Golden in proportions, being 1 in height and 1.6 in width.

The concept of relative dental proportions is also seen in nature as a whole. When these 'golden proportions' occur, they are found to be naturally and universally pleasing. Applying this 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.

The 'proportion' was usually judged using three teeth to each side of the midline. There is however, a compromise position. 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 one looks at front two teeth we see that they have a 160% width to height ratio, which is the 'proportion.' Therefore, there are three areas where the 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.

DOMINANCE OF THE CENTRAL INCISORS

Your two maxillary incisors (2 front teeth) should be symmetrical and their width should be 80% of their height with a perpendicular midline.

Using this principle one looks at the width to height proportions of the maxillary central incisors. Ideally, the width should be 75% to 80% of the height of the individual teeth. One can also judge how symmetrical they are, and whether the midline runs perpendicular. Finally, we look at whether the incisal edges run parallel to the inter- papillary, an imaginary line drawn across your pupils and the incisal edge of the front teeth. The vast majority of the populations have incisors between 10 mm and 11.5 mm long.

The curve of your maxillary incisors (2 front teeth) should match or silhouette the curve of the laterals (teeth beside front teeth). The laterals should silhouette the cuspids (eye-teeth) and so on.

In looking at a patient's silhouettes one looks to see that the teeth have a consistent curve as they progress into the back of the mouth. Specifically, we look at three measurements:
1. Anterior - distal of central to distal of lateral
2. Posterior - cuspid to premolars and molars
3. Decreasing gradation

The embrasures between the maxillary centrals (2 front teeth) should be the smallest with the respective embrasures gradually getting larger to the cuspid (eye-teeth). This creates the illusion of delicate laterals. After analyzing a patient's silhouettes, one looks at the progression of their incisal embrasures. This progression should ideally be a gradual one.

The contact points should follow the smile line and silhouette the lower lip. o grade the progression of contacts, one can judge how the upper and lower bites come together.

The vertical axis should be perpendicular and begin to angle mesially (toward the centre) from midline to posterior teeth.

The pattern of axial alignment should be consistent, starting from the patient's midline. They don't necessarily have to be perpendicular, but should run parallel to each other.

When you are smiling we should see no more than 3mm of gum tissue. Also the gum crests between teeth should follow the smile line.

When one looks at a patient's gingival contour, we want to see that the lateral incisor is at or below the imaginary line between the height of the gingival from the maxillary central incisor to the gingival at the cuspid.

When we look for occlusion, we're looking for any obvious smile irregularities. These can include a loss of vertical dimension, a vaulted narrow palate or an anterior open bite.

First one looks at the color of the teeth relative to the patient's overall skin tone. Does it complement their skin tone or contrast it to such an extent that it draws undue attention to the teeth. One can also look at whether all of a patient's teeth are a uniform color, whether there are large disparities between individual teeth, and whether there is any obvious general discoloration of the teeth in general.