1. Impaction

Unemerged tooth, commonly wisdom tooth.

Teeth start to pass through the gums (emerge) during infancy, and again when the primary (baby) teeth are replaced by the permanent teeth. If a tooth fails to emerge or emerges only partially, it is considered to be impacted. An impacted tooth remains stuck in gum tissue or bone for various reasons. It may be that the area is just overcrowded and there’s no room for the teeth to emerge. Impacted wisdom teeth are very common. They are often painless and cause no apparent trouble. However, in some cases an impacted tooth pushes on the next tooth, which pushes the next tooth, eventually causing a misalignment of the bite. A partially emerged tooth can trap food, plaque, and other debris in the soft tissue around it, leading to inflammation and tenderness of the gums and unpleasant mouth odor.