A palatal expander is a common orthodontic appliance used primarily for children and adolescents to correct discrepancies in the width of the upper jaw (maxilla). The device applies gentle forces to widen the maxilla, creating necessary space for permanent teeth and correcting the bite. While highly individualized, the duration of this treatment generally follows a predictable timeline involving two distinct phases.
What Palatal Expanders Do
The expander addresses a narrow maxilla, a condition that often results in a posterior crossbite. The upper jaw is composed of two halves joined at the midline by the midpalatal suture. In growing patients, this suture has not yet fully fused, making it pliable and responsive to mechanical pressure.
The fixed appliance, typically anchored to the upper molars, uses a central jackscrew mechanism to exert a gentle, controlled outward force. This pressure gradually separates the two halves of the palate along the midpalatal suture. The resulting expansion creates additional room in the dental arch, which can help alleviate dental crowding and improve the alignment of the upper and lower teeth.
The Two Phases of Expander Treatment
The total duration an expander remains in the mouth is typically between six and twelve months, encompassing two distinct treatment periods. The initial period is the active phase, which is defined by the process of turning the central screw with a special key. This rapid expansion phase usually lasts only a few weeks to about three months, depending on the amount of widening required.
During the active phase, the expander is activated once or twice daily, generating the necessary force to separate the palatal halves. A visible gap often appears between the two front teeth, which is a sign that the skeletal expansion is successfully occurring. Once the orthodontist confirms the desired width has been achieved, the active turning ceases, and the appliance is locked into place.
The subsequent and longer period is the retention or stabilization phase, which is necessary for treatment success. The expander remains untouched in the mouth to act as a fixed retainer while the body solidifies the expansion. This phase allows new bone tissue to form and mineralize within the gap created at the midpalatal suture.
This bone consolidation process typically requires the expander to stay in place for an additional four to nine months after the turning stops. Combining the active and retention phases ensures that the newly widened jaw is structurally stable and prevents the palate from relapsing to its original position.
Why Treatment Timelines Vary
The overall timeline for expander treatment is influenced by several biological and mechanical factors unique to each patient. A major variable is the patient’s age, as younger individuals generally have shorter treatment times. Before puberty, the midpalatal suture is less ossified, meaning the bone structure is more flexible, allowing for faster and more predictable expansion and bone stabilization.
The severity of the initial narrowness directly affects the duration of the active phase. A patient requiring minor widening will complete the turning phase faster than someone with a significant transverse deficiency. Complex cases often necessitate a longer active period to reach the targeted skeletal correction.
Patient compliance with the turning schedule is another influence, particularly during the active phase. Following the prescribed turning regimen ensures a steady and controlled expansion, avoiding delays from inconsistent schedules. Non-compliance can prolong the active phase, extending the duration of the entire treatment process.
After the Expander Comes Out
Once the retention period is complete and the new bone has formed, the expander is removed, marking the end of the first stage of orthodontic treatment. The expanded maxilla provides the foundation, but the teeth often still require individual positioning and alignment. Therefore, the expansion phase is frequently followed by comprehensive orthodontic treatment, such as traditional braces or clear aligners.
The full set of braces may be placed immediately after removal, or a partial set may have been placed earlier. The goal of this subsequent treatment is to perfect the bite and align all the teeth into the newly available space. Alternatively, some patients transition to a removable retainer to maintain the corrected width until all permanent teeth have erupted and are ready for the next phase of care.