The maxilla, or upper jawbone, is a complex, paired bone structure that forms the central part of the face and anchors the upper teeth. Its proper position and size are foundational to facial aesthetics, bite alignment (occlusion), and nasal airway function. When the maxilla is underdeveloped or positioned incorrectly, it can lead to problems like dental crowding, crossbites, and compromised breathing, often contributing to obstructive sleep apnea. Improving the maxilla involves correcting its transverse width, vertical height, and forward projection to optimize both function and facial balance.
The Foundation of Maxillary Development
Maxillary growth is heavily influenced by environmental and behavioral factors, particularly during childhood when the facial bones are still pliable and rapidly developing. The continuous practice of nasal breathing is one of the most significant factors in promoting proper development of the midface complex. Nasal airflow provides a constant stimulus that encourages the maxilla to grow in a forward and horizontal direction, helping to establish a wider arch and a lower palatal vault.
Conversely, chronic mouth breathing, often caused by nasal obstruction, is associated with detrimental changes to the craniofacial structure. When a person breathes through their mouth, the tongue drops from its natural resting position, reducing pressure on the upper jaw. This lack of upward and lateral pressure results in the maxilla developing a narrower, higher-arched shape. This altered growth pattern can cause the maxilla and mandible to rotate backward and downward, contributing to an increased anterior facial height and a less projected midface.
The correct resting position of the tongue, where the entire dorsum rests against the roof of the mouth, provides an internal orthopedic force that promotes lateral maxillary growth. The continuous pressure acts as a natural palatal expander, especially during rapid skeletal maturation. Maintaining this posture helps counteract the inward pressure from the cheek muscles, which encourages the narrowing of the dental arch.
Diet and chewing habits also play a substantial role in stimulating bone density and shape through mechanical loading. Chewing requires significant force, which sends signals to the osteocytes (bone cells) to regulate bone reconstruction. Masticating harder foods, as opposed to a predominantly soft diet, generates greater force, enhancing growth factors and promoting bone formation. This mechanical stimulation helps the jawbone adapt to its environment, resulting in stronger structure and influencing the overall morphological development of the jaw.
Non-Surgical Orthopedic and Orthodontic Approaches
When functional habits alone are insufficient to correct a narrow maxilla, clinical interventions are often necessary, falling under the category of orthopedic and orthodontic treatment. Palatal expansion is the primary non-surgical method used to physically widen the maxilla and correct transverse discrepancies. This procedure is indicated for issues such as posterior crossbites, dental crowding, and to increase the nasal airway volume for improved breathing.
The effectiveness of non-surgical expansion is directly related to the patient’s age, specifically the maturity of the mid-palatal suture connecting the two halves of the maxilla. In children and adolescents before the mid-teen years, this suture is still flexible, making expansion highly effective. The most common device is the Rapid Palatal Expander (RPE), which is cemented to the teeth and uses a central screw mechanism. The RPE is activated daily, applying a strong force that causes the mid-palatal suture to separate, achieving the desired width within a few weeks.
For older adolescents and adults whose mid-palatal suture has become fused and rigid, a different approach is required to achieve skeletal, rather than just dental, expansion. Maxillary Skeletal Expanders (MSE) or Mini-screw Assisted Rapid Palatal Expanders (MARPE) utilize skeletal anchorage for more efficient force transmission. These devices are anchored directly into the palate bone using small, temporary screws in addition to being attached to the teeth.
By anchoring the expander directly to the underlying bone, MSE/MARPE bypasses the rigid tooth-to-bone connection and minimizes undesirable tipping of the teeth, maximizing skeletal separation. This technique achieves true skeletal expansion even in skeletally mature patients, offering a less invasive alternative to surgery for adults with mild to moderate transverse deficiencies. Following the active expansion phase, a retention period allows new bone to mineralize in the space created along the suture. Orthodontic alignment, typically using braces or clear aligners, then finalizes the treatment.
Surgical Options for Maxillary Correction
In cases where the maxilla requires substantial repositioning, or when the underlying skeletal discrepancy is too severe for non-surgical expansion, surgical intervention becomes the necessary course of action. Orthognathic surgery, or corrective jaw surgery, is performed by an oral and maxillofacial surgeon and is often the solution for significant functional and aesthetic problems. The most common procedure for the upper jaw is the LeFort I osteotomy, which allows the surgeon to separate the tooth-bearing portion of the maxilla from the rest of the facial skeleton.
This full mobilization of the maxilla enables movement in all three dimensions: forward or backward (sagittal plane), up or down (vertical plane), and side-to-side (transverse plane). Indications for a LeFort I include correcting severe malocclusion, addressing midface hypoplasia (underdevelopment), and treating vertical maxillary excess, which involves shortening the upper jaw. The surgery is also frequently performed to enlarge the upper airway in patients suffering from obstructive sleep apnea.
A separate surgical procedure, Surgically Assisted Rapid Palatal Expansion (SARPE), is specifically designed for adults with a transverse deficiency whose maxillae are too rigid for devices like the RPE or even MSE. SARPE combines the use of an orthodontic expander with specific bone cuts, or osteotomies, performed by the surgeon. These cuts typically involve a partial LeFort I cut and separation of the pterygomaxillary junction to strategically weaken the bony resistance points.
After the bone is surgically mobilized, the patient begins activating the expander over a period of weeks to achieve the necessary width. The surgical component of SARPE facilitates skeletal separation that is impossible with non-surgical devices alone in skeletally mature patients. Both LeFort I and SARPE require significant planning, including preoperative orthodontics. A dedicated recovery period involving a modified diet and restricted physical activity is necessary while the bone heals in its new position.