Impacted wisdom teeth: the signs, and when they need removing

Wisdom teeth are the last to come through, usually between eighteen and twenty-five, when the jaw has almost run out of room. That is why they so often come through at an angle, stay buried, or only partly emerge, causing pain, swelling and damage to the tooth in front. Not every wisdom tooth has to be removed, but you should not wait for severe pain before having it checked.

What wisdom teeth are

Wisdom teeth are the third molars, one in each corner of the mouth, four at most. Many people are missing one or more from birth, or have them buried in the bone where they never erupt. A wisdom tooth that comes through straight, with enough room, and can be cleaned can be kept like any other tooth.

Signs of an impacted wisdom tooth

• A dull ache or bouts of throbbing pain at the back corner of the jaw, sometimes spreading to the ear or temple.
• Red, swollen gum behind the last molar, painful to touch, sometimes with pus, and bad breath.
• Difficulty opening the mouth, painful swallowing, swollen glands under the jaw when the infection is severe.
• Food constantly trapped at the back corner that is hard to clean.
• The molar in front (the second molar) becoming sensitive, decaying on its back surface, or a feeling that the lower front teeth are getting more crowded.
• Mild fever and tiredness during a flare-up.

Many impacted wisdom teeth cause no symptoms for years and are only found on an X-ray, by which time the second molar in front has already decayed or its root has been resorbed.

When a dentist advises removal

• The tooth is tilted or lying sideways, pressing on the second molar.
• The tooth is partly through, with a flap of gum over it that keeps getting infected.
• The tooth is decayed and cannot be filled well because it is so far back, or it is causing decay in the tooth in front.
• There is a cyst or other lesion around the crown on the X-ray.
• Before orthodontic treatment or certain restorative work, as part of the plan.
• The tooth has no opposing tooth, is over-erupting and biting into the gum of the opposite jaw.

When to watch rather than remove

• The tooth is straight, has room, meets an opposing tooth and can be brushed.
• The tooth is fully buried, with no symptoms and no lesion on the X-ray; the dentist schedules periodic X-rays. At Asahii Dental Clinic each X-ray is kept in your record in the clinic's system so the dentist can compare one visit with the next, and you can view them too.
• A general medical condition makes surgery unsuitable for now; the dentist controls the infection and keeps watching.
• The tooth lies close to the nerve canal and the surgical risk outweighs the benefit at that time.

Removing or keeping is a weighing of benefit against risk for each individual tooth; there is no rule that fits everyone.

What the X-ray shows

Looking in the mouth only shows the part of the tooth that has emerged. A panoramic X-ray shows which way the tooth lies, whether the roots are curved or straight, how close it is to the nerve canal in the lower jaw or the sinus in the upper, whether there is a cyst, and whether the second molar is affected. For teeth close to the nerve the dentist may take a cone-beam CT scan to plan a safer removal. So if you are at the age when wisdom teeth come through, one check-up X-ray is reasonable even without pain.

Is removal something to dread?

Wisdom tooth removal is a minor procedure under local anaesthetic. A tooth that has come through straight can be removed quickly; a buried one needs the gum opened and sometimes the tooth divided to take it out. Afterwards there is usually swelling and soreness for a few days, and some care is needed. At Asahii, wisdom tooth surgery is carried out by Dr. Tran Van Thang, the clinic's oral surgeon; for a tooth close to the nerve canal he plans the removal on a cone-beam CT scan and explains the risks, the options and the cost to you beforehand, so you agree before a date is set. See Preparing for and recovering from wisdom tooth removal.

When to see us straight away

• Swelling spreading to the cheek or down the neck, difficulty opening the mouth or swallowing.
• High fever and feeling very unwell with pain at the back of the jaw.
• Pus draining from the gum around the wisdom tooth.
• Severe pain not relieved by ordinary painkillers.
• Unusual numbness of the lip or chin.

These can mean the infection is spreading and needs early treatment. Only an examination and X-rays can tell whether your wisdom tooth should be removed or watched. See our general dentistry page or book an appointment by hotline 0928 888 121, Zalo or the Mini App; the clinic is open every day of the week, 08:30 to 19:00, so a flare-up at the weekend does not have to wait.