The procedure commonly known as “wiring the jaw shut” is medically termed Maxillomandibular Fixation (MMF) or Intermaxillary Fixation (IMF). This technique involves temporarily securing the moveable lower jaw (mandible) to the stable upper jaw (maxilla) to prevent movement. MMF immobilizes the jawbones, allowing underlying fractures or surgical corrections to heal in the correct anatomical and dental alignment. Achieving proper dental occlusion, the way the upper and lower teeth meet, is a central goal of this stabilization process.
Reasons for Maxillomandibular Fixation
Maxillomandibular fixation is required for specific medical conditions involving the jaw structure. The most frequent indication is a fracture of the mandible, particularly in tooth-bearing areas. MMF helps restore and maintain proper dental occlusion while the fracture heals, serving as either the definitive treatment or an aid to other surgical procedures.
MMF is also a standard part of orthognathic surgery, which involves corrective repositioning of the jawbones. In these cases, MMF ensures the newly positioned bones remain stable during the initial healing phase. It can also be used to stabilize a fracture temporarily before open reduction and internal fixation (ORIF) surgery is performed, or to manage certain temporomandibular joint (TMJ) disorders.
The Different Methods of Jaw Fixation
The technical process of jaw fixation has evolved, but the traditional method remains widely used, especially for trauma cases. This conventional approach relies on arch bars, which are narrow metal strips contoured to fit along the dental arch of both the upper and lower teeth. These arch bars are secured to the teeth using numerous small stainless steel wires looped around the neck of each tooth and twisted tightly. The arch bars feature small hooks or cleats that face each other on the upper and lower jaws.
The actual fixation occurs when the surgeon connects the hooks on the maxillary arch bar to the hooks on the mandibular arch bar. This connection is achieved using small ligature wires or elastic bands, which hold the upper and lower jaws tightly together in the correct bite. While highly effective at maintaining a rigid hold, this technique is time-consuming to apply and can make oral hygiene difficult.
IMF Screws
Newer techniques offer alternatives that may reduce the associated complications of arch bars. One method involves using intermaxillary fixation (IMF) screws, also known as skeletal anchorage devices. These small screws are temporarily inserted directly into the bone of the upper and lower jaws, providing anchor points without the need for wires around every tooth. The upper and lower screws are then connected with wires or elastic bands to achieve the necessary immobilization.
Rigid Internal Fixation (ORIF)
Another advancement is rigid internal fixation (ORIF), which often reduces the duration or necessity of MMF altogether. This technique involves surgically exposing the fracture and using small titanium plates and screws to hold the bone fragments together directly. While MMF may still be used during the surgery to guide the bone fragments into the correct occlusal position, the plates and screws provide long-term stability, allowing the patient to regain jaw movement almost immediately. The choice between methods depends on the type and location of the fracture, the quality of the patient’s teeth, and the surgeon’s preference.
Immediate Post-Procedure Care and Management
The immediate post-operative period focuses heavily on safety and acute symptom management. A primary safety concern with MMF is the risk of aspiration, particularly if the patient vomits, since the mouth cannot be opened. Patients are instructed to bend over or roll onto their side if nausea occurs, allowing liquid contents to flow out through the gaps between the teeth. A severe choking or breathing difficulty requires immediate action.
Patients are provided with specialized wire cutters and trained, along with family and friends, on the emergency protocol. The wire cutters must be kept accessible at all times. Only the wires connecting the upper and lower jaw should be cut in a true life-threatening emergency, as cutting the arch bar wires complicates the situation. Following any emergency wire cutting, the patient must contact the surgeon immediately for replacement.
Pain and swelling are managed in the first 48 hours following the procedure. Ice packs are applied to the face to minimize initial swelling, which typically peaks around the third day. Liquid pain medication is prescribed, or tablets may need to be crushed and mixed with liquid for administration. After the initial 48 hours, moist heat is recommended to help reduce bruising and speed up the resolution of swelling.
Adjusting to Daily Life with a Fixed Jaw
Living with a fixed jaw for the typical four- to eight-week healing period requires significant lifestyle adjustments, particularly concerning nutrition. The fixation necessitates a completely liquid or pureed diet, as no chewing is possible. All food must be blended until it is thin enough to pass through a straw, syringe, or the small spaces between the teeth.
Maintaining adequate nutrition is challenging, and patients are advised to consume six to eight small, high-calorie meals daily instead of three large ones. Nutritional supplements like protein powders, liquid meal replacements, and blended fruits and vegetables are necessary to prevent weight loss, which can impair healing. Patients must avoid alcohol, as it can induce nausea and vomiting, increasing the risk of aspiration.
Oral hygiene is difficult but important to prevent infection and tooth decay around the fixation hardware. Patients must use a small, soft-bristled toothbrush, often a child-sized one, to clean the outer surfaces of the teeth and the hardware after every meal. Frequent rinsing with salt water or a prescribed antimicrobial rinse helps flush out food particles and maintain a clean environment.
Communication is difficult, and the patient may have trouble being understood in the initial weeks. Speaking slowly and distinctly is necessary, and carrying a notepad for complex conversations can help reduce frustration. The psychological adjustment to the temporary loss of normal function requires patience and support throughout the healing process.