What Is Lip Incompetence?

If you’ve seen “Napoleon Dynamite,” I’m sure you can recall the title character’s open-mouthed appearance in the quiet moments before he uttered popular phrases like, “Gosh!” or “Tina, you fat lard, come get some dinner!”

The term that describes the open-mouthed condition of John Heder, the actor who played Napoleon Dynamite, is “lip incompetence.”

Canadian actress Amanda Crew who played Monica Hall on HBO’s sitcom “Silicon Valley” is one example of a celebrity with lip incompetence.

The term describes the lips’ inability to comfortably rest together in a closed position without straining the muscles around your mouth. Those who have lip incompetence often exhibit dimpling and buckling in their chin, or a slight tugging at the tip of their nose when pressing their lips together because doing so causes subtle stretching of the soft tissue around the mouth. It also may cause the upper and lower lip to protrude slightly.

This may not sound like a problem to be addressed by an orthodontist, and it’s true that the root cause of lip incompetence doesn’t always relate to a person’s tooth alignment or bite. However, untreated lip incompetence can lead to orofacial changes that alter your tooth alignment and your bite, and lead to changes in facial appearance.

If you’re a parent, you might feel relieved to know that not every child who breathes with his/her mouth open or maintains an open-mouth appearance while the teeth are together has lip incompetence. Children’s lips continue to grow until age 12 or 13, so children sometimes will outgrow the condition.

We routinely recommend that children be evaluated by an orthodontist at age 7, and the case of lip incompetence is one of many reasons why. At age 7, your child has a combination of baby and adult teeth, and the bite has developed. In most cases, no treatment is needed at this age. We simply monitor your child as they grow. If the lips don’t rest together comfortably when the jaws are together, this is something we will observe at those monitoring appointments to determine whether it’s a case of the lips haven’t caught up yet in the growth pattern, or if something else is at play causing the condition.

Causes of Lip Incompetence

One common cause of lip incompetence is chronic allergic rhinitis. This is nasal inflammation that is caused by airborne allergens, and symptoms include runny nose, nasal congestion and sneezing. The inability to breathe comfortably through the nose leads to mouth breathing.

While anyone can have a gummy smile, this condition is more common in women than men.

Lip incompetence also can be a sign that there is nasal obstruction, enlarged tonsils or enlarged adenoids.

Can Lip Incompetence Lead to Other Problems?

A 2005 study published in Collegium Antropologicum concluded that lip incompetence plays an important role in growth and development of the craniofacial complex. Researchers have discovered changes in facial development, tooth eruption and alignment, breathing, swallowing and jaw joint function as a result of lip incompetence.

Children who consistently breathe through the mouth are at the greatest risk of experiencing orofacial changes because their bodies are still growing and developing.

Over the course of time, lip incompetence in children limits forward growth and promotes vertical facial growth that gives the face a long, narrow appearance, often referred to as “long face syndrome.” The palate can become narrow and highly arched, and children can develop overjet, overbite or crossbite. Overjet and overbite can cause the chin to recede and become set back too far in relation to the upper jaw. This leads to a less attractive facial profile.

Mouth breathing also can cause the lower jaw to drop down slightly to an open position to help facilitate oral breathing, according to an article on OrofacialMyology.com

Because the upper lip cannot comfortably rest in its proper position, it can fail to develop properly and eventually become too short. As a result, children may develop a “gummy smile,” where they show too much gum tissue when smiling broadly.

Mouth breathing due to lip incompetence also can lead to increased risk of snoring and sleep apnea in children and adults, which disrupts sleep patterns. That can lead to fatigue, decreased productivity and poorer quality of life. It may seem difficult to imagine, but in some cases the root cause of children’s misbehavior and poor performance in the classroom could be traced back to the problem that created lip incompetence and mouth breathing.

Other issues caused by lip incompetence include speech errors and droopy eyes.

Treatment for lip incompetence

A comprehensive evaluation is required to create an ideal treatment plan that adequately addresses the effects of lip incompetence. Treating the orofacial effects typically requires that the root cause first is identified and addressed to help ensure orthodontic problems related to lip incompetence don’t recur after treatment is complete.

Once a treatment plan is identified, hardware such as palatal expanders and Herbst appliances may be recommended. A palatal expander is used to widen the palate in children who are still growing. A Herbst appliance addresses overjet and recessed lower chin by pulling the upper jaw to promote backward growth.

Another treatment option is orofacial myofunctional therapy, provided the cause of the lip incompetence is due to problems such as swallowing abnormalities or the improper rest posture of the tongue.

The medical term for a gummy smile is excessive gingival display.

Orofacial myofunctional therapy involves simple exercises that activate particular facial muscles. When these muscles are activated, other muscles will follow suit until proper coordination of the tongue and facial muscles is attained, according to the Academy of Orofacial Myofunctional Therapy.

Lip repositioning may be another option for some patients to address lip incompetence and a gummy smile. A surgeon can “lower” the upper lip by removing a strip of tissue from the inside and suturing the exposed area to a new, lower position.

For patients who have a significantly recessed chin, surgery to move the chin bone forward may be called for to reduce chin strain.

Learn More

Do you or your child have lip incompetence? Call our office to schedule an appointment for a comprehensive evaluation. We will conduct a thorough exam complete with X-rays and photographs to develop a treatment plan designed to meet your unique needs. We look forward to seeing you soon.