What does this mean?
Normal mouth opening is close to three fingers wide. Falling clearly below that happens in two main ways: the chewing muscles contracting because of inflammation (trismus), or the disc in the jaw joint blocking movement.
What separates them is what comes with it. Fever, swelling and difficulty swallowing point to infection, and that is an emergency. Restriction that is painless or mildly painful and comes with a click is joint-related.
Restriction from infection needs assessment within hours; the joint-related kind also responds far better early on.
Likely causes
What helps at home?
- Do not try to force the mouth open
- Eat soft food for a while
- If it is joint-related, a warm compress relaxes the muscles
- Fever, swelling or difficulty swallowing alongside it
- Difficulty breathing: go to the nearest emergency department
- Opening dropping below two fingers
- The jaw locking open and not closing
Frequently asked questions
- My mouth won't open after a wisdom tooth extraction; is that normal?
- Some restriction in the first days is expected and improves steadily. Increasing restriction, fever or swelling should be assessed.
- Does locking release by itself?
- Sometimes it does, but it tends to recur. With repeated locking, early assessment clearly improves the outcome.
This content is for general information and does not replace an in-person examination. Symptoms overlap between conditions, and a diagnosis can only be made clinically.