Can wisdom teeth cause bad breath?

Wisdom teeth, or third molars, are the last teeth to come in, usually in the late teens or twenties. Often there is not enough room, so they come in at an angle, only partly break through the gum, or stay trapped (impacted). MouthHealthy, from the American Dental Association, notes that wisdom teeth can trap food, are hard to floss around, and that bacteria can get into the gums around a partly erupted tooth.

That trapped material is broken down by the same kinds of bacteria that make sulfur gases elsewhere in the mouth, which is why the smell can be strong and is often paired with a bad taste on one side at the back.

Pericoronitis is inflammation of the gum around a wisdom tooth that has not fully come through. A gum flap called an operculum covers part of the tooth, and food, bacteria and debris collect underneath it. Cleveland Clinic lists the symptoms this way:

• Chronic (long-term): mild, temporary aching near the back teeth, bad breath and a bad taste in the mouth.
• Acute: severe pain, red swollen gum, pus or drainage, discomfort swallowing, difficulty opening the mouth (lockjaw), facial swelling, swollen neck glands and fever.

With treatment, Cleveland Clinic says pericoronitis usually settles within a week or two, but it can come back if the tooth stays partly covered.

The NHS lists pericoronitis, food getting stuck, decay, gum disease, cysts and abscesses among reasons wisdom teeth are removed.

• Brush the back carefully. Angle a small-headed or end-tuft brush to reach behind and around the wisdom tooth.
• Floss or use an interdental brush between the wisdom tooth and its neighbor.
• Rinse with warm salt water after meals. For pericoronitis symptoms, Cleveland Clinic suggests warm saltwater rinses three to four times a day and an alcohol-free antibacterial mouthwash twice a day.
• Use a water flosser on low to flush food from under a gum flap, if your dentist agrees.
• Clean your tongue. It will not reach the wisdom tooth, but it removes the coating that adds to the overall smell.

If the smell comes back every time you stop doing these things, the tooth's position is likely the real problem, and that is a conversation for your dentist.

A dentist can clean under the gum flap, treat infection and, if needed, prescribe an antiseptic rinse or antibiotics. For pericoronitis that keeps returning, options include removing the gum flap or removing the wisdom tooth. Many wisdom teeth never cause trouble, so removal depends on symptoms and X-rays, not on bad breath alone. If you have a wisdom tooth taken out, see bad breath after tooth extraction for what to expect while it heals.