Definition: The eruption of a tooth into an adjacent tooth preventing it from completely erupting onto the occlusal plane.
Location: Most commonly associated with permanent first molars and primary second molars.
Shape: May have cupping due to resorption from adjacent tooth pressure on crown and root.
Internal: Radiolucent, where tooth structure is missing.
Number: Usually single, but may be multiple.
(note the permanent first molar ‘erupting’ into the primary second molar causing resorption)
(note the maxillary left second molar ‘erupting’ into the first molar with resorption of the first molar)
(bilateral ectopic eruption on the maxilla of the permanent first molars into the primary second molars)