Maxillomandibular fixation (MMF)

Maxillomandibular fixation (MMF) can be used either intraoperatively to establish the correct occlusion or as part of the postoperative management of the patient's injury. MMF may be accomplished with wires or training elastics depending on the patient’s overall treatment plan.

Internal fixation techniques in dentate patients begin with re-establishing the occlusion, ensuring maintenance of pre-injury occlusal status. There are several techniques that provide maxillomandibular fixation (MMF). Many surgeons agree that the gold standard for establishing MMF is the use of arch bars. However, various methods of MMF can be used in specific clinical situations.

Standard MMF methods are:

• Arch bars (described in this text)
• Ernst ligatures
• Bone supported devices including intermaxillary fixation (IMF) screws, hanger plates, and inter-arch miniplates
• Interdental wires

There are other wire fixation methods such as Ivy loops, Gilmer wiring, Stout wiring, and Kazanjian buttons.

AO Teaching video on maxillomandibular fixation (MMF)

One pitfall when using arch bars is the risk of stick injuries. Passing the wires to secure the arch bar can result in a puncture or tear in the surgeon's glove and the possibility of disease transmission to the surgeon.

Universal infection control must be ensured for every patient, regardless of the disease status of the patient. Adequate protective barriers, as well as techniques, are essential to prevent stick injuries.

The use of double gloves provides a second protective barrier. The lower number of perforations in the inner gloves demonstrates the effectiveness of double gloving.

Consider changing gloves in the following circumstances:

• When the outer glove is torn
• When wetting is seen beneath the outer glove
• Every 120 minutes
• After every arch

The following techniques may help to prevent stick injuries:

• Whenever possible, implement MMF in a surgical setting with an assistant
• Handle sharps carefully
• Try to use a “non-touch technique” with wires, grasping the wires with wire twisters only and not touching them with fingers
• Always grasp loose ends at the tip to avoid leaving a wire tip “open”
• Discard cut wire pieces in a sharps container

Before inserting the arch bars, check the occlusion. There should be full interdigitation of the teeth with regular contacts.

Determine if there is a normal occlusion or a preexisting malocclusion before taking the patient to the operating room.

The prefabricated arch bar must be adjusted in length and contoured to fit the dental arch. The arch bar should not damage the gingiva.

The arch bar should be placed between the dental equator and the gingiva.

The bar should be trimmed to allow ligation to as many teeth as possible. The bar should not extend past the most distal tooth or protrude into the gingiva as this will be a source of irritation to the patient.

Hooks are placed facing away from the occlusal surfaces and symmetrically in the upper and lower jaw to achieve properly directed forces on both bars when the patient is placed in MMF. This symmetry is essential for functional training with elastics.

To fix the arch bar in place, prepare a ligature in the premolar region of each side. Ensure the wire ends do not damage the surrounding soft tissues.

Position the arch bar with one end of the wire above and the other end below it.

Secure the arch bar by twisting the circumdental wire using a wire needle driver.

Always twist the wire in a clockwise direction.

Cut the wire with the wire cutter and turn the ends (rosettes) away from the gingiva to prevent damage.

Ensure the wire rosettes do not protrude away from the arch bar, as this will irritate the soft tissue.

The photograph shows arch bars applied to the mandible and maxilla.

The wire loop is placed over the arch bar's maxillary and mandibular hooks, and is tightened.

MMF is completed with wire fixation. At least three wires are required to provide stable fixation (a posterior wire loop on each side, and an anterior wire loop).

Some surgeons prefer MMF with elastics for intraoperative management of the occlusion. Additionally, postoperative training elastics can be used to manage condylar fractures.

Click here for a description of Ernst ligature application.

Click here for a detailed description of bone-supported devices and their application.