• Facial esthetics that are impacted by orthodontic treatment include the teeth, smile line, facial muscle tone, lip support, lip display, gum display, profile, facial balance, symmetry of the face, and facial appearance with eating and swallowing.
  • All of these aspects of facial esthetics can be adversely affected by an orofacial myofunctional disorder.

The Teeth

  • The alignment of the teeth is the first thing associated with orthodontic treatment and the treatment result would be poor if the teeth are not straightened nicely during treatment.
  • The overlap of the teeth is also very important for the esthetics of the teeth.
  • The top front teeth should be approximately 1 to 2 mm ahead of the lower front teeth and the upper front teeth should overlap 1 to 2 mm vertically over the lower front teeth.
  • The biting edges of the upper front teeth should be on a curve that approximately matches the curve of the upper lip upon smiling.

The Smile Line

  • The smile line is the line of the lips at rest and upon smiling. When smiling, the lips should curve upwards at the outer edges.
  • At rest, the lips should be horizontal.
  • It is fairly common that the lips form a downward curve at the outer edges of the lips. This is called a reverse smile line and gives the impression that the person is frowning which is not esthetically desirable.
  • A reverse smile line is often associated with a vertical growth pattern in which the jaws have grown downward more than normal due to an orofacial myofunctional disorder.
  • The resulting increased length of the face from the nose to the lip is too long for the lips to close together in a relaxed manner and the lower lip has to strain in order to touch the upper lip which causes the outer edges of the lips pull downward creating a reverse smile line.

Facial Muscle Tone

  • The muscles of facial expression are used for smiling, frowning, grimacing, kissing or a multitude of other expressive actions used in communication and interaction.
  • When the face is relaxed, the muscles of facial expression should be relaxed with the mouth closed and the lips together.
  • When an orofacial myofunctional disorder has altered the balance of the facial muscles a number of negative consequences can occur to facial esthetics.
  • The cheek muscles (buccinators) can be too tight, creating dimples.
  • The lips (orbicularis oris) can be too tight resulting in diminished lip display and an impression of anxiousness.
  • The chin muscle (mentalis) can be too tight, creating an impression of stress or anger.

Lip Support

  • In profile, the lips should be on a line connecting the tip of the nose with the tip of the chin.
  • When the lips are in front of or behind this line the lip support is compromising the facial esthetics.
  • This lip support is mostly dependent upon the positioning of the front teeth. Orofacial myofunctional disorders can result in the front teeth being tipped too far forward or too far back for ideal esthetics.

Lip Display

  • The normal display of the lips for nice esthetics is approximately the same amount of lip display for upper and lower lips.
  • The amount of the vermillion border display is approximately 10 to 12 mm for each of the upper and lower lips.
  • The amount of lip display can be reduced due to an orofacial myofunctional disorder such as a reverse swallow or a lip tightening habit.

Gum Display

  • The amount of gum display upon a full smile is normally around 0 to 2 mm.
  • When the gum display is more than this there is a “gummy smile”.
  • The occurrence of a gummy smile can be due to an unusually short upper lip, an upper lip tie, or an excessive vertical growth pattern.
  • A short lip or an upper lip tie, are generally genetic traits.
  • An excessive vertical growth pattern is generally due to an orofacial myofunctional disorder.
  • When the tongue rest posture is not in the palate the jaws grow in a more vertical direction, with the result that the upper jaw is lower in the face than normal and the teeth and gums show excessively.


  • A pleasing profile has the upper and lower jaws matching well front to back with the line of the lower jaw angled downward only mildly.
  • When the upper jaw is too short in relation to the lower jaw it appears that the lower jaw is protruding excessively and the facial profile is straight.
  • When the lower jaw is too short in relation to the upper jaw the profile is quite convex and it appears that there is a “weak” chin.
  • When the line of the lower jaw has a pronounced downward slope there is a “vertical growth pattern” and the face appears to be excessively long. This is a common facial growth pattern in chronic mouth breathers.
  • Deficiencies in facial profiles are often the consequence of an orofacial myofunctional disorder.

Facial Asymmetry

  • An esthetically pleasing face is normally symmetrical.
  • Facial asymmetries detract from the esthetics of the face.
  • Asymmetries can be the result of genetic syndromes, trauma, or orofacial myofunctional disorders.
  • The nose could be positioned slightly off the centre of the face due to trauma.
  • The chin could be shifted to one side as a result of a  narrow upper jaw that causes a crossbite of the back teeth on one side that, in turn, forces the jaw to shift to one side.
  • One side of the face can be less developed than the other side due to an orofacial myofunctional disorder. This can result in one eye and/or ear being lower than the other or the lower jaw being tipped down on one side relative to the other.

Facial Appearance with Eating

  • When chewing and swallowing, the facial muscles around the mouth should not be active.
  • The lips, the chin muscle, and the cheek muscles should be relaxed during eating.
  • If these muscles are active it is a sign of an orofacial myofunctional disorder and eating in this manner is not esthetically pleasing.
  • Eating with an open mouth is often noisy and is considered poor manners. Open mouth chewing is the result of an orofacial myofunctional disorder.
  • Parents of children in treatment in our office are generally very pleased when we can change their child’s noisy open mouth chewing to quiet and polite chewing.