A crossbite is a specific type of malocclusion, or improper bite, characterized by the upper teeth resting inside the lower teeth when the mouth is closed. This misalignment can affect a single tooth, a segment of teeth, or an entire arch. Crossbites are broadly categorized based on their location: an anterior crossbite involves the front teeth, where the upper teeth sit behind the lower front teeth, while a posterior crossbite affects the back teeth. Since adult patients have fully developed and fused jawbones, treatment planning for correction focuses on moving teeth within the bone or altering the underlying skeletal structure.
Consequences of Untreated Crossbite
Untreated crossbites lead to long-term oral health issues due to abnormal forces exerted during chewing. The continuous, uneven pressure causes premature and excessive wear on the enamel of the affected teeth. This accelerated wear can result in chipped or fractured teeth, increased sensitivity, and decay.
The misalignment also strains surrounding tissues, often resulting in gum recession on affected teeth. Furthermore, the persistent imbalance can stress the temporomandibular joints (TMJ), leading to chronic jaw pain, headaches, and difficulty chewing. Over time, an untreated crossbite, particularly one that causes the lower jaw to shift to one side, can contribute to noticeable facial asymmetry.
Non-Surgical Orthodontic Corrections
For adults with a primarily dental crossbite—where teeth are misaligned but the underlying jaw structure is well-proportioned—non-surgical methods are the standard approach. Traditional fixed braces apply continuous pressure via brackets and wires, moving the teeth into the correct buccolingual position. This process remodels the bone surrounding the tooth roots, allowing them to shift.
Clear aligner therapy, such as Invisalign, can also be effective for mild to moderate dental crossbites. These custom-made trays apply programmed forces to sequentially move the teeth over the course of treatment. Attachments, which are small, tooth-colored buttons bonded to the teeth, are often used with aligners to provide the leverage needed for complex movements, including correcting a crossbite.
In some posterior crossbite cases involving slight upper arch constriction, minor dental expansion may be attempted without surgery. Specialized appliances, such as a Quad-Helix expander or certain archwires, can be used to tip the molars outward to achieve a correction of a few millimeters. This approach relies on moving the teeth within the alveolar bone rather than separating the midpalatal suture, which is fused in adults.
Surgical and Skeletal Correction Methods
When a crossbite is skeletal—indicating a mismatch in jaw width or position—surgical intervention is often necessary for a stable, functional result. The severity of the skeletal discrepancy determines the type of surgical procedure required. A severe anterior crossbite caused by an overly prominent lower jaw or a retruded upper jaw typically requires orthognathic surgery.
Orthognathic surgery involves repositioning the jawbones, often using procedures like the Le Fort I osteotomy (upper jaw) or bilateral sagittal split osteotomy (BSSO) (lower jaw). These operations physically move the maxilla and/or mandible into the correct anatomical relationship. Orthodontic treatment with braces or aligners is always performed both before and after the surgery to align the teeth within their newly corrected jaw positions, a process known as surgical orthodontics.
For posterior crossbites where the upper jaw is significantly too narrow, the midpalatal suture is too ossified for non-surgical expansion. Specialized procedures like Surgically Assisted Rapid Palatal Expansion (SARPE) or Micro-Implant Supported Expansion (MARPE) are utilized to widen the palate. SARPE involves an oral surgeon surgically weakening the maxilla and midpalatal suture, allowing an expander to successfully widen the arch. MARPE achieves a similar result using temporary skeletal anchorage devices (TSADs) or mini-implants embedded in the palate to achieve skeletal separation.
Duration, Retention, and Cost Considerations
Adult crossbite correction generally involves a longer treatment timeline than treating the condition in children. Non-surgical orthodontic treatment typically takes between 18 months and three years to complete, depending on the complexity of tooth movements. Skeletal corrections involving orthognathic surgery add significant time, including a preparatory orthodontic phase, the surgery itself, and a final post-surgical phase.
Once active tooth movement is finished, the retention phase begins, which is a lifelong commitment. Retainers, which can be fixed (a thin wire bonded behind the teeth) or removable (such as a Hawley retainer or clear plastic aligner), are worn to prevent corrected teeth from shifting back toward their original crossbite position. This is particularly important because the periodontal ligaments and surrounding bone require time to stabilize the new position.
The financial commitment for adult crossbite correction varies widely based on the chosen method and its complexity. Non-surgical orthodontic treatment generally falls within a predictable range, though it represents a significant investment. When skeletal correction methods are necessary, the total cost increases substantially due to the inclusion of surgical fees, hospital costs, and the extended duration of combined orthodontic and surgical treatment.