Tooth impaction

Impacted and embedded teeth are the two main types of unerupted teeth found in the mouth, and can sometimes be confused with each other. In both cases, the teeth remain below the surface of the gum and ,often, bone, rather than erupting into an exposed position within the mouth; however, the reason for the failure to erupt differs. Impacted teeth result from a situation in which an unerupted tooth is wedged against another tooth or teeth or otherwise directed so that it cannot erupt normally. In contrast, an embedded tooth is an unerupted tooth that is covered, usually completely, with bone. The former is "physically" blocked in its path of eruption, while the latter is compromised by its lack of eruptive force often without known etiology. Certain systemic and local pathologic conditions may be associated with both (i.e., cleidocranial dystosis)..
Mandibular third molars are the most commonly found unerupted teeth, while maxillary third molars are second most common.