why does my jaw not open properly after wisdom tooth pain

If you can fit only one or two fingers between your front teeth instead of the usual three, and it all started with an ache at the back of your mouth, your jaw is not "locked" in the joint. It is almost always the muscles, reacting to something going on around the wisdom tooth.

What is happening

The lower wisdom tooth sits right next to the muscles that close your jaw, especially the masseter (the thick muscle at the angle of your jaw) and the medial pterygoid (a muscle on the inside of the jaw). When the area around the tooth becomes inflamed or infected, these muscles tighten up to stop you moving the sore area. This protective tightening is called trismus.

The common causes

• Pericoronitis: infection of the gum flap over a partly erupted wisdom tooth. Food and bacteria collect under the flap; the gum swells, the upper tooth bites on it, and it swells more. This is by far the most common cause in young adults. See our page on pericoronitis.
• A spreading infection from a decayed wisdom tooth or an abscess (a pocket of pus), which can track into the spaces around the jaw muscles.
• After an extraction: stiffness for a few days after wisdom tooth surgery is common, from the procedure and from keeping the mouth open for a while. It should get better day by day.
• Injection site: occasionally the nerve-block injection used for lower teeth causes a sore, stiff muscle for some days.

When it is urgent

Trismus with infection should be examined within a day or two, not left for weeks. It becomes urgent if you have any of these:

• Swelling spreading under the jaw, into the neck or up towards the eye.
• Difficulty swallowing your own saliva, or difficulty breathing.
• High fever, or feeling generally very unwell.
• Opening getting rapidly worse over hours.

Call us on 8484 990 678; Kharadi is open until 11 PM, seven days. After hours, these signs need a hospital emergency department, not a wait until morning. More on our emergency dentist page.

What your dentist will do

The first step is to treat the infection, not to pull the tooth immediately. Your dentist cleans and flushes under the gum flap (a localised cleaning; our current published fee for it is ₹1,000), may relieve the upper tooth if it bites on the swollen gum, and may prescribe medicines. Antibiotics are used when there are signs of spreading infection, not routinely. Once the mouth opens comfortably again, usually in some days, the decision about removing the wisdom tooth can be made calmly. Repeated episodes are a strong reason to remove it, and these cases are planned with our oral and maxillofacial surgery department.

What you can do meanwhile

• Rinse gently with warm saltwater, especially after meals, to keep food out from under the gum flap.
• Apply warmth to the outside of the jaw for muscle stiffness, but never heat on a swelling that is getting bigger.
• Eat soft food: dal, khichdi, curd rice, soup.
• Do not force your mouth open, and do not put tablets or clove directly on the gum.
• Avoid tobacco, gutkha and supari, which irritate the area further.

Painkillers from a chemist can hide the problem without fixing it. If your mouth opening is reduced, have it examined.