In Figure A. above is illustrated how the jaws were most often wired together when IMF (Inter-Maxillary Fixation)  was required for the healing of broken jaws.
In B. above you can see how the base arch wire for each jaw was woven through the between the teeth, and then in Figure C. how the jaws were tied together using the base arch wires. This configuration of jaw wiring (IMF) is called "Ivy" loops and was use by oral surgeons even before prefabricated preformed "arch-bars," as shown in Fig A., were created.  The patient had to be placed under general anesthesia since the wire had to be threaded  between the teeth and sometime right through the gums. As you can see the wiring between the jaws is complicated in itself and in no way could the patient undo the Ivy loop IMF. Patients would be limited to a liquid diet (which is why they lost weight) and would be wired together for 8-12 weeks.  The procedure would have taken even a skilled surgeon and hour to wire the jaws together.

Special note:

I was called upon to remove Ivy loops from a patient who lived in Brooklyn who had actually gone to England to be wired for weight loss because she wanted to try this method of weight loss and could not find a willing doctor in the US. She found me through the www.Drted.com  website and asked me to remove the Ivy loops that were used to wire her teeth together since they were at present causing her great pain. Thinking it would not be terribly difficult I undertook the work. As an orthodontist I do not give any injections for anesthesia.  It didn't take too long before I realized that I had made a mistake in this endeavor to remove the Ivy loops. It took all of 45 VERY UNCOMFORTABLE minutes to complete the removal. In retrospect I should have stopped a few minutes into the procedure and sent the patient to an oral surgeon who I'm sure would have given her as a minimum a "full mouth" of local anesthesia to make the removal painless. It takes two painless minutes to remove OJW (Orthodontic Jaw Wiring). Moreover, any general dentist no less an orthodontist could place OJW in under thirty minutes.