Anterior Segment Aesthetic Ratio

Aesthetic Zone ratios is one of many ways to evaluate the appearance of a patients smile, and also to plan for changes that will improve overall aesthetics.

In the last article on using aesthetic zone ratios we looked at comparing the width to the height. This ratio allows us to gather data and diagnose issues like vertical maxillary excess and hypermobile lip that cause this ratio to be larger than normal.

Anterior Segment Ratio

The next of the four ratios compares the width of the total esthetic zone, all of the teeth visible between the commissures at a full smile, and the width of just the anterior segment, between the distal of the canines. The first thing to do is measure the two distances. This can be done in pixels by inserting a line over a full smile photo, or measured with a mm ruler on a printed photograph. Make sure your line is placed at the inside of the soft tissue near the commissures. The relationship to real width is irrelevant as we are going to use a ratio. We then divide the width of the anterior segment by the width of the esthetic zone and multiply by 100.

Arch Width Ratio= (Anterior Segment Width/ Esthetic Zone width) x 100

Smiles that are rated as attractive have an anterior segment width ratio between 59-75%, and the average ratio is 66%. The percentages do not have a gender or age bias which makes relying on these numbers easy. If the ration is too small or too large I start to wonder about arch space issues. Often with patients with a large midline diastema you will see this ratio be larger than 75%. In these cases or cases with inadequate space I want to make sure we use wax-ups and mock-ups to ascertain that we can meet the patients aesthetic demands without the addition of ortho to the treatment plan.

Lee Ann Brady DMD

Dr. Lee Ann Brady is passionate about dentistry, her family and making a difference. She is a general dentist and owns a practice in Glendale, AZ limited to restorative dentistry. Lee’s passion for dental education began as a CE junkie herself, pursuing lots of advanced continuing education focused on Restorative and Occlusion. In 2005, she became a full time resident faculty member for The Pankey Institute, and was promoted to Clinical Director in 2006. Lee joined Spear Education as Executive VP of Education in the fall of 2008 to teach and coordinate the educational curriculum. In June of 2011, she left Spear Education, founded leeannbrady.com and joined the dental practice she now owns as an associate. Today, she teaches at dental meetings and study clubs both nationally and internationally, continues to write for dental journals and her website, sits on the editorial board of the Journal of Cosmetic Dentistry, Inside Dentistry and DentalTown Magazines and is the Director of Education for The Pankey Institute.

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