A palatal expander is a common orthodontic appliance primarily used to correct a narrow upper jaw. This device, usually recommended during childhood or early adolescence, is designed to gently widen the maxilla (upper jawbone). The treatment is considered a form of interceptive orthodontics, addressing skeletal issues while the patient is still growing. By widening the upper arch, the expander creates necessary space for permanent teeth to erupt correctly and helps improve the alignment of the bite. This fixed device can often prevent the need for more extensive orthodontic procedures later in life.
Understanding Palatal Expanders
The most common appliance is the Rapid Palatal Expander (RPE), a fixed device attached to the upper back teeth, typically the molars, using metal bands. The main structure consists of two halves connected by a central expansion screw that rests against the roof of the mouth. This screw applies the controlled, gradual force required for the widening process.
The success of the expander relies on the anatomy of the upper jaw, which is composed of two separate bones joined at the midline by the midpalatal suture. In children, this suture is not yet fused and remains flexible. The RPE works by exerting lateral pressure against the teeth and the palate, which slowly stretches and separates this central suture.
Over the course of the active treatment phase, new bone material regenerates in the space created by the separation, making the upper jaw permanently wider. While the RPE is the standard for skeletal expansion, other versions exist, including slow expanders or removable appliances. These alternatives may be used for less severe cases or for minor dental movement rather than true skeletal widening. The fixed nature of the RPE ensures continuous force, which is necessary for predictable correction of the jaw structure.
When and Why Expanders Are Recommended
Orthodontists recommend palatal expansion to correct structural and alignment issues, aiming for a harmonious relationship between the upper and lower jaws. The primary indication is a posterior crossbite, where the upper back teeth bite inside the lower back teeth. A narrow upper jaw also leads to dental crowding because there is insufficient space for permanent teeth to erupt correctly. Widening the arch creates several millimeters of space, reducing the likelihood of future tooth extractions. A narrow upper jaw can also contribute to an incorrect jaw relationship, potentially causing uneven wear on the teeth or functional issues.
Expansion can also improve the patient’s airway. This may alleviate difficulties with nasal breathing or sleep-related issues.
The timing of this intervention is a significant factor in its success, as treatment is most effective before the midpalatal suture fully solidifies. This process, known as ossification, usually occurs during the final stages of puberty. Treatment is often initiated during the mixed dentition phase, typically between the ages of seven and ten, while the jaw is still pliable. Addressing the skeletal discrepancy during this period of active growth allows the orthodontist to modify the jaw’s growth pattern, maximizing the biological response and long-term stability.
The Treatment Process and Daily Care
The palatal expander is custom-made for each patient based on molds or digital scans, and placement involves cementing the appliance onto the back teeth. The initial treatment begins with the activation phase, which involves turning the central screw with a small, specialized key. A parent or guardian is typically responsible for this daily action, following the orthodontist’s instructions. Each turn is precisely calibrated to move the device 0.25 millimeters, often requiring one or two turns per day.
As expansion progresses, a noticeable gap (diastema) often appears between the upper front teeth, signaling that skeletal separation is occurring. Once the prescribed expansion is achieved, the activation phase stops. The device then remains in the mouth for the retention phase, acting as a fixed retainer. This holds the jawbones in position while new bone fills the gap at the midpalatal suture. This phase typically lasts for three to six months to ensure the skeletal change is stable before the expander is removed.
Proper daily care is necessary throughout the treatment period, focusing on hygiene around the appliance. Cleaning the expander requires careful brushing, often using an end-tuft toothbrush or a water flosser to remove trapped food particles. Patients may experience temporary side effects, including minor discomfort or pressure after a turn, which can be managed with over-the-counter pain relievers. Speech may also be affected initially, causing a temporary lisp, but the tongue adapts quickly. Adhering to a temporary diet that avoids sticky, hard, or chewy foods is also important to prevent damage to the appliance.