Wisdom Tooth Extraction

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Wisdom Tooth Extraction

What are Wisdom Teeth?

Most adults have 32 permanent teeth – 16 each on both the upper and lower jaw. Our third permanent molars, also known as the wisdom teeth, usually erupt between the ages of 17 to 25. There are 4 wisdom teeth, located at the ends of the upper and lower jaws. It is common to have one or more wisdom teeth missing. For some people, their wisdom teeth can normally erupt, while for some others, their wisdom teeth may not successfully erupt and may become impacted.

Wisdom Teeth Erupt

For most people, their wisdom teeth will be blocked from erupting completely in the mouth by the permanent second molars or the surrounding bone and/or gums due to the smaller jaw space. These wisdom teeth are considered to be impacted. Treating impacted wisdom teeth is the most common reason why your dentist will recommend them to be extracted.

The impacted wisdom tooth may partially emerge (partially impacted), showing only the crown of the tooth, or never emerge through the gums at all (fully impacted). The wisdom tooth may also grow at an angle towards or away from the second molar, or grow at a right angle, almost as if it is “lying” down.

Possible consequences of impacted wisdom teeth

Pericoronitis (Usually seen in the lower jaw)
Food debris and bacteria are easily trapped in the space between the crown of the wisdom tooth and the overlying gingiva (gum), resulting in the infection of the surrounding tissues (Pericoronitis). Furthermore, the infected, swollen overlying gingiva is easily hurt by the opposing upper tooth making it difficult to recover. Pericoronitis has the following signs and symptoms:

  • Pain and swelling of the cheek
  • Difficulty in opening the mouth
  • Pain when swallowing
  • Swollen lymph nodes in the neck
  • Fever
  • Bad breath

Tooth decay
Since it is difficult to clean the surfaces between the impacted tooth and the adjacent tooth in front, dental plaque will accumulate there and cause tooth decay on these tooth surfaces.

Root resorption of the neighbouring tooth
The inflammation of the surrounding tissues caused by the dental plaque, together with the pressure of the wisdom tooth pushing on the adjacent tooth in front, may cause the root of the adjacent tooth to resorb.

Causes pathological changes
e.g. cysts


If the impacted tooth is completely embedded in the jaw bone, or if the partially erupted wisdom tooth has no discomfort and doesn’t cause any problem to adjacent tissues, it may not be necessary to remove it. However, one must keep good oral hygiene to prevent any problem. On the other hand, if the impacted wisdom tooth causes frequent discomfort or causes severe problems, it may have to be extracted. Consider removal of impacted wisdom tooth

  • Severe problems associated with wisdom tooth
    • Frequent inflammation of gingivae covering the wisdom tooth causing
      recurrent Pericoronitis
    • Suffered from severe Pericoronitis
    • Severe decay, gum disease, pulpitis or periapical infections of wisdom tooth
    • Impacted wisdom tooth causing root resorption of adjacent teeth
    • Cyst around the wisdom tooth can damage the structure of jawbone.
      (If there is a cyst formation, the cyst together with the impacted wisdom tooth must be extracted.)
  • Prior to the following treatments
    • Extraction of mal-positioned wisdom tooth prior to orthodontic treatment
    • Radiotherapy
    • Jawbone reconstruction surgery

Procedures on surgical extraction of impacted wisdom tooth:
It has to take balance between the risks and benefits of the surgical extraction of tooth. In some cases, the impacted wisdom tooth is deeply embedded in the jaw bone and its roots are close to main nerve, surgical extraction may impose risk of damaging the nerve, leading to numbness of the mouth. Therefore, the decision on removal or not or when to remove the wisdom tooth is dependent on clinical situation.

The dentist will take radiographs to confirm the position and shape of the wisdom tooth, and explain to the patient on the situation, procedures and any risks. Usually, the procedures will be done under local anaesthesia (numbness of mouth only), but in some cases, it may be done under general anaesthesia or under sedation. The procedures should be painless.

There are five main steps:

  1. Raise the gum flap
  2. Remove the covering bone
  3. If needed, cut the tooth into few parts
  4. Rinse and clean the wound
  5. Close the wound with sutures, and stop the bleeding

One week after extraction, remove the sutures by the dentist who will check the healing of the wound. If the suture is of self dissolve type, then it is not necessary to remove the sutures by the dentist. However, it is still necessary to let the dentist to check the healing of the wound. In general, the wound will heal within 2 weeks.