An impacted tooth is a tooth that fails to fully emerge. The most common teeth to become impacted are wisdom teeth. These teeth normally emerge between the ages of 17 and 21 and it is very common for them to become impacted. When a tooth is impacted, it remains embedded in soft gingiva (gum) tissue or bone beyond its normal eruption time. This can cause overcrowding, and sometimes the impacted tooth will push on the next tooth, which can cause a misalignment of the bite.