Maxillary Skeletal Expansion (MSE) is a treatment designed to widen the upper jaw (maxilla), particularly in adults where the midpalatal suture is fused. Unlike traditional expanders that primarily move teeth, the MSE device uses temporary anchorage devices (TADs) to apply force directly to the bone structure. This non-surgical process gently separates the fused palate, correcting a narrow upper jaw, improving the bite, and often enhancing the nasal airway. Understanding the timeline is important, as the procedure involves distinct phases that span many months.
Preparing for MSE Placement
The journey toward skeletal expansion begins with a comprehensive evaluation and planning phase. This initial stage ensures the procedure is appropriate and tailored to the patient’s anatomy. The orthodontist uses advanced imaging, typically a Cone-Beam Computed Tomography (CBCT) scan, which provides a detailed three-dimensional view of the jawbone and surrounding structures.
The CBCT allows the clinician to measure the palatal bone thickness, assess the degree of midpalatal suture fusion, and virtually plan the exact position for the MSE device and its mini-implants. Based on this digital planning, a custom MSE appliance is fabricated, a process that typically takes several weeks. This customization ensures the force is directed precisely to achieve true skeletal separation.
Once the custom appliance is ready, the placement procedure is quick, generally taking less than an hour under local anesthesia. The MSE is anchored directly to the palate using the temporary devices. The preparation phase concludes when the device is secured, marking the start of clinical treatment.
The Active Expansion Period
The active expansion period is when the patient physically turns the MSE device to generate widening force across the palate. This is the shortest, but most intensive, phase, focused on achieving skeletal separation. Patients are typically instructed to turn the device one to two times per day, though some protocols may involve up to four turns initially to help open the suture.
Each turn applies a small, controlled amount of pressure, gradually widening the midpalatal suture. The total duration of this active turning phase usually ranges between three to six weeks, depending on the required expansion and the patient’s biological response. In some cases, this phase can extend up to ten to twelve weeks.
The speed of expansion depends on the individual’s bone density and age. Once the target width is achieved, a small gap often appears between the two upper front teeth, confirming successful skeletal separation. At this point, active turning stops, and the device transitions into its retention role.
Stabilization and Bone Consolidation
Following the active turning phase, the MSE device remains in the mouth passively to allow the newly expanded suture to stabilize. This stabilization and bone consolidation phase is the longest part of the MSE treatment and is necessary for long-term success. The separated bone segments must be held firmly in their new position to prevent immediate relapse.
The MSE acts as a static retainer, creating a fixed scaffold that bridges the newly created space. The purpose of this extended retention is to allow new bone tissue to mineralize and grow across the opened midpalatal suture, a process known as osseous integration. This new bone formation makes the expansion permanent and prevents the upper jaw from narrowing again.
The typical duration for this consolidation phase is between three to six months. This timeframe ensures that the soft, immature bone is replaced by stronger, mature bone, providing a stable foundation. The MSE appliance is only removed once the clinician confirms, often through imaging, that sufficient bone consolidation has occurred.
The Full Treatment Sequence
While the MSE device is in place for a total of four to eight months, this is usually just the initial step in a complete orthodontic treatment plan. The MSE widens the jaw, but subsequent treatment is required to align the teeth and refine the bite. The space created by the expansion, including the gap between the front teeth, must be closed and the back teeth correctly interlocked.
The MSE phase is nearly always followed by comprehensive orthodontics, such as traditional braces or clear aligners. The total duration of this subsequent orthodontic stage varies widely based on the complexity of the patient’s bite and alignment needs. The overall commitment from initial MSE placement to the final removal of all appliances typically ranges from 18 to 30 months.