 This permits a moderate amount of jaw movement and relatively clear speech, but inhibits the ingestion of solid foods, forcing patients to adhere to a liquid diet.The type of jaw wiring used in patients with mandibular fractures, or those who need orthognathic surgery to correct deformed jaws, is known as inter-maxillary fixation (IMF) or maxillo-mandibular fixation (MMF).It is performed by an oral surgeon, who attaches an "arch bar" to the upper jaw and another to the lower jaw with thin wires that are threaded between and around the teeth.