An impacted tooth is a tooth that fails to fully pass through the gums.
Teeth emerge through the gums during infancy, and when the primary (baby) teeth are replaced by the permanent teeth. If a tooth fails to emerge, or emerges only partially, it is impacted. Because they are the last teeth to emerge, the most common teeth to become impacted are the wisdom teeth (the third set of molars), which normally emerge between the ages of 17 and 21.
An impacted tooth remains embedded in soft gingiva (gum) tissue or bone beyond its normal eruption time. The cause may be overcrowding, often because the jaw is too small to fit the third set of molars. Teeth may also become twisted, tilted, or displaced as they try to emerge, resulting in impacted teeth.
Impacted wisdom teeth are very common. They are often painless and cause no apparent trouble. However, sometimes an impacted tooth will push on the next tooth, which pushes the next tooth, eventually causing a misalignment of the bite.
