Once upon a time, before advances in agriculture led to the softening of the foods humans consumed, there was more than enough room in the human jaw for wisdom teeth. However, today, when wisdom teeth erupt between the ages of 18-24, there often isn't enough room to accommodate them. This leads to them becoming impacted.
Put simply, because of the lack of available room, wisdom teeth often become trapped beneath bone and gum tissue, and may also erupt at awkward angles. This is the reason that so many Australians opt to have their wisdom teeth extracted, with 527 people out of 100,000 having impacted teeth removed from 2008 to 2009. Not all cases are the same. When a wisdom tooth erupts, partially or otherwise, at a 45 degree angle (mesio-angular), extraction is generally the best course of action.
Mesio-Angular Eruption Causes Crowding
Although the process does take time, eventually, if a wisdom tooth leans against the second molar, the force of this pressure will cause the second molar to move. Coupled with mesial drift which is the natural occurrence of teeth drifting forward over time, the teeth at the front (anterior) of the mouth will become overcrowded.
Even if such a tooth causes little discomfort then, within a few years, other dental issues may arise. When teeth become overcrowded, the bite suffers in that teeth no longer meet as they should during chewing. This can lead to bruxism (nocturnal grinding), and can cause teeth to crack or fracture. A crooked smile is also the result of overcrowding.
The Risk of Gum Disease Increases
It is much more difficult to clean the area around an angled wisdom tooth. For instance, the area of tooth and gum between the wisdom tooth and the second molar will be much harder to reach with both toothbrush and floss. Because of this, a build-up of tartar may form along the gum line, irritating the gums and causing inflammation and pain.
This is what is known as gingivitis--mild gum disease. However, unless the wisdom tooth is removed or a dental hygienist cleans the area, the gingivitis will progress to become the more serious form of gum disease, periodontitis. This is when tartar spreads beneath the gum line, forming a pocket of bacteria that will eventually damage the gums and the affected teeth.
It is true that not all impacted wisdom teeth become an issue, however, in this case, where the wisdom tooth is leaning on the second molar, extraction is the best course of action. If one of your wisdom teeth has erupted in this way, arrange for a dentist to remove it before further dental problems arise.