Etiology, Classification and Management of Ectopic Eruption of Permanent First Molars.

Ectopic eruption of a permanent tooth involves abnormal resorption of a portion or all of the adjacent primary tooth. Among the most commonly ectopically erupted teeth are the permanent first molars. Ectopically erupting molars may require intervention to allow for full eruption, or they may spontaneously self-correct and erupt into occlusion. Decisions regarding the necessity of intervention, its ideal timing, and intervention type are multifactorial. Treatment options for the ectopically erupting permanent first molar include the elastomeric separator, brass wire, pre-fabricated clip separator, custom made appliances (Humphrey appliance, Halterman appliance), or extraction of the primary molar. Early intervention when indicated can ensure proper full eruption of the permanent first molar and prevent mesial angulation, arch perimeter loss, tooth impaction and ankylosis. Two cases are described that manage ectopic eruption of the permanent first molar.