Primary and secondary impaction of four primary molar teeth in a single patient

摘要

The lack of eruption of a primary tooth can be considered rare. In primary impaction, the primary tooth not only has never appeared in the oral cavity, but also is always covered by a more or less thick layer of bone. Secondary impaction, which is relatively more common, denotes teeth that at one time erupted into the mouth, but subsequently clinically appear to have receded from this position. The purpose of this paper is to present a case of primary and secondary impaction of four primary molar teeth in a single patient.