Dental Problems: Impacted Teeth
What is an Impacted Tooth?
An impacted tooth is a tooth that is unable to fully erupt into the mouth due to blockage of its path of eruption by other teeth, bone or soft tissues. Impacted teeth may be remain fully embedded in the gums or they may be partially erupted where only part of the crown is visible above the gumline.
What are the Causes of an Impacted Tooth?
Impacted teeth are usually caused by a mismatch between the size of the teeth and the size of the jaw arch. Sometimes the teeth are too large for the space available in the jaw arch which lead to a condition called crowding. The malalignment of teeth may result in tooth impaction. Impacted teeth can also be caused by a layer of bone or hard cover of gum that blocks the path of eruption of the tooth. A tooth may also be impacted because it grows in an abnormal position or in an abnormal direction.
The most commonly impacted teeth are the third molars. Historically, human diets were very abrasive. The abrasiveness of food eaten would wear away the biting edges of the teeth. Since teeth are narrower at the neck of the tooth (the part of the tooth near the gum line), the wearing down of the biting surfaces would create gaps between the teeth. The back teeth would then migrate forwards in a process called “mesial migration” to close gaps between the teeth thus creating space for the third molars to erupt at the back of the mouth.
In modern times, our diets have become softer and less abrasive which preserve the biting edges of our teeth. This results in the third molars becoming redundant through changes in our lifestyles and diet. In some individuals, the third molars become impacted due to the lack of space in the dental arch.
What are the Effects of an Impacted Tooth?
Impacted teeth do not necessarily cause problems in the mouth. Impacted teeth that are fully submerged can remain submerged without an individual even being aware of having an impacted tooth. Occasionally submerged teeth may cause problems, such as root resorption (breaking down of the roots) of the adjacent teeth.
There is also a belief that impacted teeth push on adjacent teeth which pushes other teeth. The end result is malalignment of the teeth. There are two schools of thought on this theory – the oral surgeons that do not believe a single tooth can be the cause of crooked teeth and the orthodontists who believe that impacted teeth can lead to malalignment.
Usually it is the impacted teeth that are partially erupted that cause problems. Due to the impaction, the tooth is unable to fully emerge into the mouth. The supporting bone and soft tissue of the jaws normally form attachments to the tooth roots but they are unable to form the same attachments to the crown of the tooth. The inability to form attachments to the crown of the tooth leads to the formation of pockets under the gums where food and bacteria can be trapped. The trapped food and bacteria cause an inflammatory reaction called pericoronitis which can be very painful.
Dealing with an Impacted Tooth
Pericoronitis is generally treated with antibiotics and the removal of the pocket - this may involve removal of the entire impacted tooth or removing the flap of gum covering the crown. If most of the tooth has erupted into the mouth save a small portion under a flap of gum, sometimes all that is needed to manage the problem is careful cleaning under the gum flap. Flushing the pocket with a syringe or flossing may be sufficient. Alternatively, the crown of the tooth can be fully exposed by surgically removing the flap of gum covering the crown. If the bulk of the tooth remains beneath the gum line and there is no other way to bring the tooth into position in the arch then surgical removal of the tooth is necessary.
Impacted teeth that are asymptomatic (without problems or symptoms) do not require any treatment. The only reason for removing asymptomatic impacted teeth would be for aesthetic reasons, for instance, if your orthodontist required it.