The trend known as “mewing” has gained significant attention on social media platforms, claiming to offer a non-invasive way to improve facial structure and address dental issues like an underbite. Evaluating these claims requires separating anecdotal evidence from established health science, especially when considering complex skeletal conditions. This discussion assesses the scientific validity of using tongue posture to correct a Class III malocclusion compared to traditional orthodontic and surgical treatments.
Defining Mewing and Underbite Malocclusion
Mewing is a technique involving maintaining the entire tongue, including the back third, pressed flat against the roof of the mouth (the palate). This oral posture is promoted by the Orthotropics movement, suggesting that constant upward pressure can guide the growth and alignment of the facial and jaw bones over time. Proponents claim this habitual, resting tongue position can improve breathing, define the jawline, and potentially correct malocclusions without traditional intervention.
An underbite, medically termed a Class III malocclusion, is an alignment issue where the lower teeth and jaw protrude past the upper teeth when the mouth is closed. This condition is categorized based on its origin. A dental Class III malocclusion is caused by the misalignment of the teeth themselves. A skeletal Class III malocclusion, often called prognathism, involves a structural discrepancy in the size or position of the jaw bones, resulting from an underdeveloped upper jaw (maxilla), an overdeveloped lower jaw (mandible), or both. Skeletal issues are far more challenging to correct than dental issues.
Scientific Evidence Supporting Skeletal Correction
The idea that changing tongue posture can alter established bone structure, especially in adults, lacks support from credible, peer-reviewed clinical research. While proper tongue posture plays a role in normal craniofacial development during childhood, the forces generated by the tongue are insufficient to reverse a significant skeletal malocclusion. Orthodontic treatment relies on stimulating bone remodeling, a biological process governed by Wolff’s Law, which states that bone adapts to the load it is placed under.
Professional orthodontic appliances achieve this by applying continuous, controlled, and calibrated forces over an extended period to move teeth and guide bone growth. The force exerted by the tongue, even when pressed firmly against the palate, is not comparable to the controlled mechanical force required to counteract the genetic or developmental factors of a severe underbite. Once skeletal maturity is reached in the late teens or early twenties, facial bones stop growing and become rigid, necessitating significant force to induce structural change. No long-term, controlled studies have validated mewing as an effective alternative for correcting Class III malocclusion.
Established Treatments for Class III Malocclusion
Professional medical treatment for a Class III malocclusion is determined by the patient’s age and the severity of the underlying skeletal discrepancy. For children whose jaws are still developing, early intervention focuses on growth modification to redirect the growth of the upper and lower jaws. Orthopedic appliances, such as a reverse-pull headgear (facemask), apply forward-directed force to the maxilla, encouraging the upper jaw to catch up to the lower jaw. A chin cap appliance may also restrain the forward growth of the mandible.
In adolescents and adults with mild dental underbites, traditional orthodontics (braces or clear aligners) can correct the alignment by tipping the teeth into a better position. This process, known as dentoalveolar compensation, uses elastics to realign the teeth and camouflage minor skeletal issues. However, for adults with moderate to severe skeletal Class III malocclusion, the discrepancy is too large for teeth movement alone. These cases require orthognathic surgery (jaw surgery), which involves physically repositioning the upper and/or lower jaw bones to achieve proper alignment and facial balance. Surgery is combined with pre- and post-surgical orthodontics to ensure the teeth fit together precisely after the skeletal correction.