Lock Jaw

A locked jaw can make it difficult to open or close your mouth comfortably. This page explains common causes, when to seek evaluation, and the treatment approaches that may help restore jaw movement.

Causes of Lock Jaw

Jaw muscles can go into spasms and tighten, causing the jaw to become stuck open or closed. Locking can be structural or muscular. People often describe their jaw as “locked” when they cannot open their mouth wide enough.

  • Opening wide for a long dental procedure

  • Eating hard, crunchy, or chewy foods

  • Overusing the jaw muscles

  • Teeth grinding and clenching (bruxism)

  • Tetanus bacterial infection

  • TMJ disc displacement

  • Jaw joint dislocation

  • Trauma or injury to the jaw

  • Arthritis

  • Scar tissue or adhesions within the TMJ

  • Certain medications that can cause muscle spasm

How Long Does Lock Jaw Last?

  • It can last for several seconds to several weeks.

  • It can be persistent due to adhesions or structural changes.

How Do I Fix Lock Jaw?

  • Apply a warm compress to the jaw and facial area for several minutes to help relax the muscles.

  • Gently move the jaw side to side and back and forth to help catch the disc.

  • A specialist may recommend a manipulation procedure when appropriate.

  • Visit a specialist for ongoing care, interventions, and treatment.