Authors of section

Author

Boaz Arzi

Executive Editor

Amy Kapatkin

General Editor

Frank Verstraete

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Maxillomandibular fixation (MMF)

1. Principles

Decision making on treatment of TMJ fractures is complex. It should be based on anatomical site, patient size and age, fracture configuration and desired function. CT imaging is essential. Skull or dental radiographs are not adequate to assess the extent of TMJ fractures.

Evidence-based approach to TMJ fractures in dogs and cats is lacking. The treatments recommended here are based on clinical experience of veterinary and human CMF surgeons.

CT of a dog mandible with TMJ fracture

Restoring functionality and range of motion as well as maintaining occlusion are the primary goals of fixation of TMJ fractures.

This can be achieved by bonding the maxillary and mandibular canine teeth to each other. The disadvantage of this method is that it does not allow early return to normal function.

Maxillomandibular fixation (MMF) in a dog mandible with TMJ fracture

2. Positioning and approach

This procedure is performed through the intraoral approach, with the patient placed in dorsal recumbency or sternal recumbency.

3. Bonding of the canine teeth

Placement of an esophagostomy tube is strongly recommended prior to bonding of the canine teeth.

Placement of esophagostomy tube in a dog

The canine teeth are cleaned, acid-etched for 20-30 seconds and then rinsed with water and completely air dried.

Acid etching on canine teeth of a dog with mandible TMJ fracture

The teeth are placed in normal dental occlusion. The canine teeth are positioned overlapping each other by approximately one half of the length of the crown, allowing enough space for eating, drinking, and movement of the tongue.

Teeth of a dog with mandible TMJ fracture placed in normal dental occlusion

A composite temporization material is applied covering the canine teeth forming two pillars.

Note: Care should be taken to avoid sharp edges or points on the dental composite.

Composite placement on canine teeth of a dog with mandible TMJ fracture

Smooth the composite with a Goldie bur (titanium nitride coated) on a straight handpiece or a diamond bur on a high-speed handpiece when the composite solidifies.

Composite smoothening on canine teeth of a dog with mandible TMJ fracture

4. Aftercare

The patient should wear an Elizabethan collar until removal of the construct.

Multimodal analgesia is recommended. Non-steroidal medication for 10-14 days and opioids for the first 5 days post-surgery as needed.

The construct should be cleaned at least once daily using 0.12% chlorhexidine gluconate solution. Another option is to use a water-flossing device.

The composite is kept in place for 4-6 weeks and removed with debonding forceps under general anesthesia.

The teeth involved in the fixation should receive periodontal cleaning as moderate to severe gingivitis is seen associated with the fixation wire.

maxillomandibular fixation mmf

Panting is not possible, therefore exposure to heat is avoided. To prevent damage to the construct, avoid toys and contact with other animals. While rarely seen, if the patient vomits, aspiration pneumonia may occur.