Molars are the â€œchewingâ€? or â€œgrindingâ€? teeth at the back of your mouth. Wisdom teeth are the third molars at the very back of the teeth. There is one third molar in each of the four corners of the mouth. Wisdom teeth are the last of the permanent teeth to develop often not erupting until the late teens or early twenties. This delay means that by the time the wisdom teeth are ready to erupt there is often no room in the mouth left for them. For this reason wisdom teeth often become impacted. In dental terms the term impacted refers to teeth that have failed to fully erupt into their proper place in the mouth.
There are four types of impacts:
Mesially impactedâ€”angled forward towards the front of the mouth.
Vertically impactedâ€”in the same upright position as the rest of the teeth
Horizontally impactedâ€”positioned horizontally growing directly into the adjacent tooth
Distally impactedâ€”angled backward towards the back of the mouth
These four types can also be classified as bony or soft tissue impacts. A bony impact means the tooth is still wedged in the jaw bone. A soft tissue impact means the tooth has emerged from the jaw bone but has not yet penetrated the gums.
Symptoms of an impacted wisdom tooth may include:
Pain in the back of the jaw Bad taste Facial swelling (in severe cases)
Usually dentists opt to extract impacted wisdom teeth as these teeth can cause all kinds of problems. Partially erupted wisdom teeth can lead to:
Â· Recurring Pericorontis: A partial wisdom tooth eruption will cause a hole in the gum tissue impossible to clean effectively. Plaque and bacteria then can collect in this space and infect the surrounding gum tissue. This infection is called pericorontis.
Â· Decay: A partially erupted wisdom tooth is very difficult to brush or floss properly so the risk of cavities and tooth decay is much higher. Unfortunately dentists will have the same problems cleaning these teeth as patients do. In the case of a cavity fillings might not even be possible. Extraction is more practical a solution.
Â· Decay on neighbouring tooth: The position of the wisdom tooth can sometimes create a â€œtrapâ€? between itself and its neighbour where plaque and bacteria can collect. This can cause damage in the neighbouring tooth as well as the wisdom tooth. In severe cases both these teeth must be extracted.
Â· Periodontal disease: Bacteria that collects around the partially erupted tooth can lead to gum disease which in turn can affect the rest of the teeth as well.
Wisdom teeth that have not erupted at all can lead to:
Â· Cysts and tumours (rare but possible)
Â· Tooth crowding. Some dentists believe that as the wisdom teeth struggle to erupt they put pressure on the other teeth causing them to shift.
Â· Damage to the second molar. If a wisdom tooth attempt to erupt and is positioned in such a way that it pushes into the second molar it can cause root resorption in the second molar.
Dentists can check the condition of wisdom teeth with an x-ray then decide on an appropriate time for and course of action. The late teens or early twenties are considered a good time for extraction as the roots of the wisdom teeth may not have fully formed and the surrounding bone will be less dense. Extraction is done under local anasthetic or for more complicated cases under general anasthetic.
Dentists cannot fully explain why wisdom teeth impaction happens in some mouths but not others. Some suggest a correlation between large teeth crowding and impaction. There are also debates on the evolutionary purpose of wisdom teeth. One theory suggests that the diet of our stone-age ancestors produced â€œwear-and-tearâ€? on their teeth resulting in jawbone growth and providing space for the third molars. As modern human diets evolved jaw lines shrank and third molars remained in hiding.