Maxillary Expansion in Orthodontics

The transverse discrepancy of the maxilla is the problem that the crowding and the posterior crossbite often hide, and the maxillary expansion is the treatment that addresses the width of the arch rather than the position of the individual tooth. The clinician who diagnoses the constriction early...

The transverse discrepancy of the maxilla is the problem that the crowding and the posterior crossbite often hide, and the maxillary expansion is the treatment that addresses the width of the arch rather than the position of the individual tooth. The clinician who diagnoses the constriction early uses the growth that remains, while the clinician who treats the narrow arch in the adult meets the limits that the mature suture sets. The indication, the appliance, the protocol, and the retention determine whether the expansion produces the stable result or the relapse that the crowded arches record. This article reviews the diagnosis, the appliances, the protocol, and the retention of the maxillary expansion.

The Transverse Problem

The narrow maxilla produces the posterior crossbite, the buccal corridor, the crowding, and the functional shift of the mandible, and the shift that the patient holds to achieve the intercuspation masks the skeletal deficiency that the diagnosis must uncover. The transverse dimension also relates to the airway, because the constricted nasal floor that accompanies the narrow palate is the factor that the sleep and the breathing assessment should consider. The clinician who measures the width and the relationship of the arches rather than the crowding alone identifies the patient who needs the expansion rather than the extraction alone.

The Diagnosis and the Records

The assessment includes the clinical measurement of the intercanine and the intermolar width, the evaluation of the posterior crossbite, and the functional shift test that the clinician performs with the patient closing in the centric relation. The radiographs, the models, and the photographs complete the record, and the cone beam computed tomography is the study that the surgical or the miniscrew assisted expansion uses where the clinician must evaluate the bone and the suture.

The Appliances

The appliance that the clinician selects depends on the age, the cooperation, and the amount of the expansion that the case requires. The removable appliance suits the young patient with the small deficiency and the good cooperation, while the fixed palatal expander delivers the skeletal effect that the rapid expansion requires. The miniscrew assisted and the surgical assisted designs extend the option to the mature patient whose suture has closed, and the clinician who matches the appliance to the biology of the patient avoids the failure that the wrong device produces.

The Activation Protocol

The protocol that the fixed expander follows begins with the activation that the clinician sets and the parent or the patient performs at the home, and the rate that the appliance delivers determines the effect on the suture and the teeth. The rapid expansion of the half turn per day separates the suture and produces the skeletal change, while the slower rate tips the teeth and produces the dental change with the limited skeletal effect. The clinician reviews the patient at the interval and monitors the diastema between the central incisors, because the space that opens in the midline is the sign that the suture has separated. The active phase ends when the width is achieved, and the appliance remains passive as the retainer while the suture consolidates.

The Effects and the Age

The expansion produces the skeletal change that the young patient with the open suture achieves and the dental change with the buccal tipping and the extrusion that the mature patient risks. The age of the patient is therefore the variable that the clinician must weigh, because the boy and the girl in the growth phase respond better than the adult whose midpalatal suture has fused. The expansion also changes the nasal width and the airflow, and the improvement that the patient reports in the breathing is the benefit that the orthodontic plan can document where the airway assessment supports it.

The Stability and the Retention

The stability of the expansion depends on the retention and the overcorrection, because the suture that is not given the time to consolidate reapproximates and the crossbite returns. The clinician who overcorrects the width and retains the arch for the months protects the result, and the patient who understands the need for the retention wears the appliance that the plan requires. The relapse also follows the soft tissue and the tongue that the expansion has not changed, which is the reason that the myofunctional assessment supports the long-term stability.

The Home Care and the Comfort

The patient with the fixed expander needs the hygiene that the appliance complicates, because the food that collects under the acrylic and the bands irritates the palate and the gingiva. The clinician instructs the patient to rinse after the meal and to clean the appliance with the brush and the water, and the soft electric brush such as the BrushO helps the patient keep the teeth and the gingival margin clean around the bands. The discomfort of the first days and the pressure that the activation produces are the normal part of the treatment, and the simple analgesic and the soft diet support the patient through the active phase.

Clinical Key Points

- Measure the transverse width and test the functional shift before the diagnosis.

- Match the appliance to the age and the maturation of the suture.

- Monitor the midline diastema as the sign of the skeletal separation.

- Overcorrect the width and retain the arch long enough for the suture to consolidate.

- Support the hygiene around the appliance and the comfort during the activation.

Conclusion

The maxillary expansion restores the width that the crowding and the crossbite record, and the result depends on the diagnosis, the appliance, and the retention that the clinician controls. The practitioner who treats the transverse dimension as the part of the whole face rather than the isolated malocclusion gives the patient the stable and the functional occlusion that the growth permits.