|Image by Liam Mendes from Wikipedia|
Unlike most facial fractures that do NOT require any surgical intervention, most jaw fractures do need to be surgically repaired and typically entail wiring the jaw shut. Often, a metal plate with screws will be utilized to stabilize the fracture as well.
The reason the jaw is wired shut is so that as the broken bone heals, it heals in such a way that the way the teeth comes together is normal (in essence, the teeth act as the cast for the jaw fracture). Of course, eating is limited to liquid diet and dental care is important as brushing the teeth thoroughly will be impossible.
The wires holding the jaw shut can be removed after a few weeks, but exact duration depends on the fracture location and severity.
Zac Efron broke his jaw this weekend. CNN 11/13/13