A palate expander is a common orthodontic appliance designed to widen the upper jaw, known as the maxilla, to improve the alignment of the teeth and bite. This device works by applying gentle, continuous pressure over time to correct a discrepancy where the upper arch is too narrow for the lower arch. The primary goal of this treatment is to create additional space in the mouth, guiding proper facial and dental development, particularly in growing individuals.
The Core Mechanism of Maxillary Widening
The roof of the mouth, or palate, is composed of two halves of the upper jaw joined at the midline by the midpalatal suture. The palate expander, usually a fixed appliance, uses a central screw mechanism anchored to the upper back teeth. When the screw is activated, it applies mechanical force to slowly separate the two halves of the maxilla at the suture line.
The effectiveness of this process is highest in children and adolescents because the midpalatal suture is still pliable and has not yet fully fused, which usually occurs around the end of puberty. This separation is considered true skeletal expansion, meaning the actual bone structure is being widened. Expansion performed after the suture has matured tends to result in more dental expansion, where the teeth are simply tipped outward. The gentle tension created by the expander stimulates the body to fill the newly created gap with new bone tissue, stabilizing the expansion.
Dental and Skeletal Conditions Palate Expanders Correct
The most frequent reason for recommending a palate expander is to correct a posterior crossbite, a condition where the upper back teeth bite inside the lower back teeth. Untreated crossbites can lead to uneven wear of the teeth, asymmetrical jaw growth, and potential problems with the temporomandibular joint (TMJ). By widening the upper arch, the expander allows the upper teeth to correctly overlap the lower teeth when biting down.
The expander also plays a significant role in managing dental crowding, which occurs when there is not enough space for the permanent teeth to erupt correctly. Widening the jaw creates arch length, which can often eliminate the need for future tooth extractions. Furthermore, increasing the width of the upper jaw simultaneously increases the volume of the nasal passages directly above the palate. This can improve breathing by enhancing nasal airflow, benefiting individuals with mouth-breathing habits, snoring, or certain sleep-disordered breathing issues.
The Patient Experience: Activation and Adjustments
The process begins with the orthodontist cementing the custom-made expander onto the patient’s upper back teeth. The active phase involves using a small, specialized key to turn the expansion screw, usually once or twice a day, following the orthodontist’s specific instructions. Each turn of the screw moves the appliance about 0.2 to 0.5 millimeters per day, resulting in a gradual but noticeable widening over a few weeks.
Patients commonly feel a sensation of pressure or tightness in the palate and around the teeth immediately following a turn, which subsides quickly. A temporary gap, called a diastema, often opens between the two upper front teeth as the midpalatal suture separates. Patients may notice temporary adjustments in speech, such as a slight lisp, and some difficulty swallowing until the mouth muscles adapt to the presence of the appliance.
Retention and Long-Term Results
Once the desired width has been achieved, the active turning phase is stopped, but the expander remains in the mouth for the retention phase. This phase allows time for the newly separated midpalatal suture to solidify. The appliance acts as a passive retainer, holding the expanded position while new bone tissue regenerates and fills the space.
The retention period lasts for several months, often three to six months, to ensure the skeletal correction is stable and permanent. After the expander is removed, the patient usually transitions into other orthodontic treatment, such as braces or clear aligners, to align the teeth within the newly widened arch. This two-phase approach ensures that the foundation of the jaw is properly sized before the final positioning of the individual teeth is completed, contributing to the long-term stability.