Managing Ectopic Eruptions and Transpositions

By Andrey Horton DDS, DAOS

Ectopic eruptions are an unfortunate reality in the etiology of malocclusions. Patients with the condition present with potential treatment challenges that can hinder an ideal outcome.

Many circumstances can facilitate ectopic eruptions and, subsequently, transpositions of erupting teeth. Ectopic eruption is explained by Dr. William Proffit as malposition of a permanent tooth bud that can lead to eruption in the wrong place. This typically occurs with the maxillary first bicuspids and incisors.

Ectopic eruptions of the mandibular lateral incisors can potentially cause a transposition between the lateral incisor and canine. Interestingly, the premature loss of primary canines can lead to space closure from the distal drift of the permanent incisors more than mesial movement from the primary permanent teeth. When the eruption path of the maxillary first molar moves too far mesially, the permanent molar does not have enough room to erupt. The roots of the primary molars can then be damaged, leading to a high likelihood of maxillary crowding.

This article explores treatment in three ectopic eruption cases. Two of the cases show alignment into the ideal locations of a normal eruption. In the third case, the alignment is finished into the transposed position. What caused the malocclusion is not known in the presented cases. Common causes of the maladies are abnormal eruption sequences, ankylosed teeth, and retained primary teeth.