Maxillomandibular fixation (MMF) - Ernst ligatures

The main indications for Ernst ligatures are the following:

• Temporary fixation before definitive operative treatment
• Intraoperative MMF for simple fractures

Ernst ligatures do not provide adequate stability when dealing with complex fractures.

Consider these essential points before starting:

• The occlusion must be checked
• In patients with jaw malformations (dysgnathia), it may be impossible to use Ernst ligatures
• Mobile teeth should not be included in the ligatures
• The ligatures of the upper and lower jaw must be placed in opposite, symmetric positions for correct immobilization
• Ligatures can cause damage to the periodontium
• There is a risk of operator stick injuries

Maxillomandibulary fixation (MMF) - Ernst ligatures

An Ernst ligature is based on two teeth in contact in the same segment of the dental arch.

When possible, premolars are used in the maxilla and mandible.

Use a 0.4 mm wire of approximately 15 cm length.

Here one end of the wire is passed through the interdental space between the first molar and second premolar (number 6 and number 5).

Thread the wire back from the lingual to the buccal side via the interdental space of the two premolars (number 4 and number 5).

Pass the other end of the wire between the first premolar and canine (number 4 and number 3).

This end of the wire also goes through the interdental space between the two premolars (number 4 and number 5).

One wire end must pass below, and the other end must pass above the horizontal portion of the wire on the buccal side.

Tighten the wire with the wire needle driver, twisting it in a clockwise direction.

Add ligatures in the same way in the other three sections of the dental arches to form two symmetrical pairs.

It is important to preserve wire ends of at least 4–5 cm in length.

After assuring correct occlusion, twist the wire ends of each pair of ligatures together using the needle driver.

Take care not to break the wires; otherwise, the procedure will have to be started again.

Cut the wire ends and bend them towards the teeth to protect the oral mucosa and the operator from accidental injuries.

Additional stabilization can be obtained by using methyl methacrylate to reinforce the ligature.

Place the methyl methacrylate around the wire. Use the monomer (liquid) for the final molding.

If complete immobilization is not tolerated, or if less stability is needed, elastics can be used.

To accommodate elastics, bend the wire ends to form little hooks, as illustrated here. Elastics can be applied between the upper and lower hooks.