Distraction Osteogenesis Maxillary Expansion (DOME): Fixing the Deficient Maxillary Wax Rim

In Facially Generated Treatment Planning (FGTP), comprehensive, interdisciplinary treatment planning begins by setting the incisal edges of the maxillary central incisors as you would in a denture.

At Spear, adding the airway reminds us that FGTP is a 3D concept. We should never set the teeth in a denture until the anteroposterior (AP) and transverse dimensions of the wax rim are ideal. The AP and transverse dimensions have come to represent the airway.

The Challenge of a Hypoplastic Maxilla

This evolution in thought has allowed us to comprehend the impact of a hypoplastic maxilla. It alters esthetics, function, and healthy breathing. The characteristics of a high palate and narrow arch can lead to increased nasal airflow resistance and posterior displacement of the tongue. We can all agree that the underdevelopment of the maxilla magnifies the difficulty of our cases, but most of us are stuck as to what we should do about it, especially in adults.

We routinely attempt to hide the problem by warping anatomic crown form and increasing the vertical dimension. Fixing a skeletal issue with a bur and ceramic are rarely the appropriate solution.

The typical treatment in children and adolescents is a maxillary expander. However, midpalatal suture fusion prevented this in most adults. The introduction of micro-implant-assisted rapid palatal expanders (MARPE) revolutionized our ability to split the suture in adults who had delayed orthodontic treatment during their childhood. Even with MARPE anchoring to the maxilla, many patients simply will not “split.”

From MARPE to DOME: A Less Invasive Solution

Adult patients that do not split with MARPE used to have two choices: SARPE and LeFort. SARPE loosens the maxilla and LeFort repositions it after a down fracture. The difficulty with SARPE is that the dental expander is attached to the teeth.

Therefore, the associated osteotomy has to loosen the maxilla completely. It is very invasive and includes a bilateral pterygoid plate cut, which carries a significant bleeding risk. In 2017, Dr. Stanley Liu introduced an advancement called Distraction Osteogenesis Maxillary Expansion (DOME). The technique uses the bone-borne expansion advantages of a MARPE paired with a reduced surgical intervention. The pterygoid disjunction is unnecessary because the mini-implants create the force required to alter that anatomy.

Typically, the MARPE is placed by the orthodontist. The surgery is 20-40 minutes and is possible to be done in-office. An incision is made about the mucogingival junction and LeFort 1 osteotomies are made.

Today, many patients have an intranasal approach which minimizes the swelling and discomfort associated with this incision. A vertical incision between the maxillary central incisor roots allows a piezoelectric saw to create a groove in the midpalatal suture. Osteotomes are tapped in the groove until the suture opens.

When the diastema appears, the MARPE is engaged and turned to produce at least a 1.0 mm opening before the surgery. Patients with severe posterior deviations of their septa may have them repaired at the same appointment. The expander is turned daily until an 8.0-12.0 mm diastema is created. At the completion of the expansion, orthodontics can begin to close the gap. Consolidation takes three months, and the expander is left for eight months to allow bone maturation and minimize relapse.

Clinical Outcomes and Patient Benefits

Multiple studies on DOME have been published in the last three years. They indicate an improvement in nasal breathing, reduction in nasal valve stenosis, reduction in daytime sleepiness, improved sleep quality, and a significant reduction in AHI. The advantages come from the improvement in airflow. Patients with collapsibility issues, described as flabby problems, may not improve as much. Unlike other surgical options, no major complications have been reported.