Tooth impaction

Overview
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, rather than erupting into an exposed position within the mouth, but 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 located so that it cannot erupt normally. In contrast, an embedded tooth is an unerupted tooth that is covered, usually completely, with bone. That is to say, something that is physically blocking the pathway of eruption (such as another tooth) is the case for an impacted tooth, whereas the lack of eruptive force results in an embedded tooth.

Mandibular third molars are the most commonly found unerupted teeth, while maxillary third molars are second most common.