The application of an interdental fixation device is a procedure used in the treatment of mandibular fractures. Its purpose is to stabilise or reduce a fracture. There are several types of interdental fixation devices in use these days, including arch bars, Ernst ligatures, interdental wiring, and metallic splints, among others. Such devices are widely used, are highly effective, and have low complication rates.
The application of an interdental fixation device is beneficial for patients who suffer from mandibular fractures. The devices can stabilise and reduce the fracture. The procedure is considered as a closed reduction method but is also used as an adjuvant treatment alongside open reduction.
A mandibular fracture is a fracture of the jaw or when the jawbone is broken. It is most often due to trauma. This injury is very common because of the jawbone’s lack of support and the jaw’s prominence in the face. Statistics show that the majority of such injuries occur due to vehicular accidents. The rest are caused by assaults, work-related accidents, accidental falls, and sporting accidents. These fractures can affect either the body of the jawbone, the condyle, or the angle of the mandible. They can also be simple or close, compound or open, or comminuted (in which the bone is crushed or splintered).
There are two main types of interdental fixation devices: tooth-borne devices and bone-borne appliances.
Tooth-borne devices are ideal for patients who have complete, healthy teeth. This means that they are not suitable for those with multiple missing teeth, carious or weak teeth, dental crowns, or dental bridges. If the patient does not qualify for tooth-borne devices, doctors will use bone-borne devices.
Bone-borne appliances work through bone-to-bone fixation. Some examples of these devices include:
IMF screws and other bone-borne devices are considered as a reserve method. They are most commonly used for emergency cases or if the patient’s condition or circumstances make it impossible to apply an arch bar. They are, however, not advisable for comminuted, segmented fractures, and severe displacement. They are also not used on children whose tooth buds are still in place.
Interdental fixation devices are effective in restoring a broken jawbone and keeping it fixed in place after an injury.
The specific method used in applying interdental fixation devices tends to vary depending on the device being used.
For arch bars, the following steps are followed:
For IMF screws, the following steps are performed:
Tooth-borne fixation devices are associated with several potential problems, such as:
Bone-borne fixation devices, on the other hand, are associated with fewer risks, but they have to be applied properly to achieve good stability. IMF screws, for one, may not be so stable because of the elastic wires that are used to support them. Also, when the wires are tightened too much, it can cause the fragment to rotate in a lateral direction.
“Coding for Trauma and Fractures.” American Association of Oral and Maxillofacial Surgeons. http://www.aaoms.org/images/uploads/pdfs/traumaandfractures.pdf
Sahoo NK, Mohan R. “IMF Screw: An ideal intermaxillary fixation device during open reduction of mandibular fracture.” J Maxillofac Oral Surg. 2010 Jun; 9(2): 170-172. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3244099/