Wisdom teeth (or third molars) are the last teeth to erupt on both sides of the mouth and in both jaws. If the wisdom teeth erupt fully out of the gum and are used in the bite, they are generally left in place (we call them ‘functional teeth’). However, in many cases wisdom teeth do not fully erupt out of the gum as most people don’t have enough room for them.
Hundreds of thousands of years ago the abrasive nature of the human diet made wisdom teeth very important for chewing. The food was very hard and not cooked well which wore the teeth down much quicker than we do today. The jaw bones were also much bigger and stronger than they are today which allowed the wisdom teeth to be functional teeth.
Today, we don’t need the heavy grinding capacity that early humans needed. Food is easier to eat, less abrasive and much softer. Evolution is reacting (slowly) to this fact by decreasing the size of our jaw bones and chewing muscles. The human jaw, which once comfortably held 12 molars (32 teeth total), is now often only large enough to hold eight molars (28 teeth total). Unfortunately, our jaws are getting smaller faster than our wisdom teeth are disappearing. The wisdom teeth often do not have enough room to grow properly. Eventually, thousands of years from now, humans will not have wisdom teeth as they have lost their function.
Problems associated with wisdom teeth
A number of problems can be associated with wisdom teeth depending on how far they have erupted from the bone and gum. Dentists classify wisdom tooth eruption as follows:
- Fully erupted: totally out of the bone and gum
- Partially erupted: partially out of the bone and gum
- Soft tissue impaction: out of the bone but caught in the gum
- Partial bony impaction: part way out of the bone
- Full bony impaction: totally under the bone and gum.
This classification can be further broken down according to the angulation of each wisdom tooth in relation to the other teeth:
- Mesially angled: the tooth is angled forward
- Normally angled
- Distally angled: the tooth is angled towards the back of the mouth.
If the wisdom teeth erupt fully, are functional teeth and you are able to keep them clean, we leave them alone.
However, many problems can develop if the wisdom teeth don’t erupt properly:
- Pericoronitis: this is the most common problem with erupting wisdom teeth. Pericoronitis is an inflammation (infection) of the soft gum tissue that surrounds the coronal portion (enamel-covered part) of a tooth. It can be associated with the eruption of any tooth but is most commonly associated with wisdom teeth. The inflammation occurs because the gum flap over the enamel does not seal the tooth from bacteria and plaque which get trapped between the tooth and gum leading to a painful inflammation.
- Damage surrounding teeth: a partially erupted wisdom tooth which is touching the molar in front will result in plaque build-up around both. This can lead to decay in both teeth and may result in the need for extensive treatment to save the adjacent molar or an extraction of both.
- Crowding: an erupting wisdom tooth can place pressure on the back teeth and push them out of place.
- Resorb the tooth in front: This occurs when the erupting tooth eats away the adjacent molar.
- Cyst development: an uncommon event, this occurs when parts of the tissue surrounding the tooth begin to grow abnormally. This can result in tooth and bone damage.
- The impacted wisdom tooth is a weak spot in the jaw, making fracture more likely in the event of trauma.
Should wisdom teeth be extracted?
The decision to leave or remove one or more wisdom teeth requires a careful radiographic assessment and oral examination. Because the wisdom teeth are so positioned so far back in the mouth it is often necessary to be referred for an OPG radiograph (full mouth X-Ray). An assessment of the risks versus benefits of removal will be made about each wisdom tooth. Generally the more impacted and angled a tooth is the harder it is to extract.
Local or general anaesthesia?
Removal of wisdom teeth can be performed under local anaesthesia (LA) or general anaesthesia (GA). Under LA the extraction site is numb and the patient should only feel pressure as the tooth is extracted. In the case of a GA, the patient is put totally asleep while the teeth are removed. A GA may be required for patients who are extremely nervous, have difficult extractions or require work on other teeth. The decision of LA or GA is case dependent and will be discussed in more detail.
There are a number of common events that can occur following the extraction of one or more wisdom teeth:
- Pain and discomfort: While pain is relative, all people experience some minor discomfort for the first 24 hours after surgery. That’s why we recommend people take some form of mild painkiller (such as ibuprofen or paracetamol depending upon your general medical health; please ask for more information) for the first 24 hours after extractions. If the pain is likely to be more intense we will prescribe a stronger painkiller.
- Inflammation: It is common to experience inflammation of the gum around the extraction site. Some people may also experience minor facial swelling. If this occurs, it may be appropriate to place intermittent ice packs (20 minutes on, 20 minutes off) for 24 to 48 hours following the extraction.
- Nerve damage: While it is uncommon, during the extraction it is possible for some nerves to be stretched and bruised, especially for lower wisdom tooth extraction. This will commonly lead to altered sensation in the lips and tongue. In most cases sensation will return to normal over a period of weeks to months and it is very rare for the sensation not to return.
- Sinus problems: The roots of the upper wisdom teeth are located close to a nasal sinus (the two sinuses close to the teeth are the maxillary sinuses). Sometimes during the extraction the floor of the sinus may get damaged. This is generally not a problem but if you notice any unusual signs (such as fluid in your nose or air passing through the extraction site) please let us know.
- Dry socket: Occasionally the blood clot will fall out of the extraction site, exposing bone. Sometimes this is uncomfortable and requires a visit to our surgery so we can place a soothing dressing over the bone. A dry socket does not alter healing.
- Sore lips and cheeks: Sometimes excessive pressure is placed on the cheeks and lips during the extraction. The cheeks and lips should go back to normal over a few days.
- Jaw joint soreness: Existing jaw joint problems can be exacerbated by the extraction of any tooth, not just wisdom teeth. Acute exacerbations of joint problems should settle down over time.
- Natural variation in healing capacity: Each person heals differently. Even with a perfect surgical procedure, some people can experience delayed healing for a variety of reasons unrelated to the procedure itself. Our team supports all patients through the healing phase, whether they happen to be quick or slow healers.
Our aim is to help you understand the problems that might be associated with wisdom teeth and your various treatment options.