Orthodontics and Facial Beauty, Part IV: Mid-line Discrepancy


In the past few posts, I’ve shown examples where our patients started out with pretty straight teeth, but because the manner in which the teeth were positioned within the lips led to imbalances in the profile, lips, and smile.  This post will address another such example that we deal with routinely in our practice.  When the teeth are not centered in the smile, we call this a mid-line discrepancy.  

Mid-line discrepancies are very common in our patient population (people who have come to us because of crooked teeth or a bite related problem).  Most pre-orthodontic patients have some degree of mid-line discrepancy in either the upper or lower teeth, and sometimes in both.  Mid-line discrepancies are often an indication of a more significant functional problem with the manner in which the back teeth bite together.  Upper mid-line discrepancies can detract from the beauty of the smile, and today I’d like to show you the treatment of an adult patient who had an upper mid-line discrepancy.

Here is an initial photograph of a patient who had pretty straight teeth, but the upper mid-line is not aligned with her nose or the center of her upper lip.  The little dip at the top edge of our upper lip is called the cupid’s bow, and the upper teeth should be centered with the cupids bow.

A closeup picture of her teeth shows that the upper mid-line does not line up with her lower mid-line either.  This was an indication to us that there was a bite problem with the way in which the back teeth were biting together. Correction of her bite problem would correct the problem with her upper mid-line as well.

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A progress photo taken part of the way through treatment shows that the mid-lines have been aligned with each other as the bite problem is being corrected.  This patient wore Speed braces, and had her upper left second premolar tooth removed to provide the necessary space to correct her upper mid-line discrepancy, and to correct the bite problem that was primarily on the left side of her mouth.

Here is a picture of her final result.  You can see that her upper mid-line now is in perfect alignment with her nose and her cupids bow.

If we look at a closeup photo of her teeth after treatment, you can see that her upper mid-line is now almost perfectly in line with her lower mid-line.  Her bite problem was corrected, and her dentist remade the porcelain crown on her upper left front tooth that had begun to deteriorate.  The patient’s concerns about her upper mid-line deviation, and her dentist’s concerns about her bite being off were both addressed with her orthodontic treatment.

Smiling is an expression that conveys pleasure, happiness, friendliness, and amusement.  Therefore, it is one of the most important features associated with facial beauty.  In our last few posts, we have written about how subtle things (like how much gum tissue shows when we smile broadly, if our teeth are not level with our eyes and other facial features, or if our teeth are not well centered in our face) can detract from the appearance of our smiles.  More importantly, it can create a self-conscious smile in which we seek to hide our true smile.  Our happiest of smiles (one that involves our mouth AND our eyes) is called a Duchenne smile, named after the 19th century neurologist Guillaume Duchenne who discovered that we have two kinds of smiles-a “fake” smile that involves our mouth only, and a “true” smile that involves our mouth and our eyes.  Recent research shows that it is only our “true” smile that is associated with positive emotions.  For these reasons, it is important that we not be self-conscious about our smiles.  When we are happy, we need to show that we are happy-without reservation.  In this way, we are able to convey to the world that we are friendly, happy, and approachable.  Anything less, and we might send the wrong message to those around us.

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