Can lockjaw be caused by chewing gum?

Metal gum. Not the lockjaw process you get from tetanus. If chewing gum causes you jaw claudication, you need to see a ENT or maxillofacial specialist. On the other hand and as a fellow gum chewer, switch brands, get the softest, sugarless gum you can.
Lockjaw. Lockjaw was a symptom of tetanous infection. Rather rare. If you mean can your jaw lock because of chewing gum. If you have some TMJ problems, the chewing of gum may overwork fatiqued muscles and cause cramping, pain, and stress on your joint. The joint may lock open, like after a yawn, or lock close with limited opening and bite out of whack.
No. Lockjaw is usually caused by the mouth being opened very wide for long periods of time. As in long dental procedures. The jaw muscles go into spasm, preventing closure. Muscle massage and proper bilateral downward pressure by your doctor will unlock the jaw.