Mesial Ectopic Eruption of the Permanent First Molar: Report of Three Cases

Abstract

Mesial ectopic eruption of the permanent first molar (MEE) is characterized by the mesial impaction of the molar beneath the distal cervical region of the adjacent primary second molar. Its etiology is multifactorial and includes dentoalveolar size discrepancy, reduced maxillary width, and congenital anomalies such as cleft lip and palate. It may cause atypical root resorption of the primary second molar, premature loss, reduction of arch perimeter, and impaction of the second premolar; therefore, early diagnosis and treatment are essential. Objective: To describe the evolution and therapeutic management of three patients who presented different degrees of reversibility of MEE. Case presentation: Case 1: A 7-year-old female patient with EEM of tooth 16, eruption failure of tooth 11. Tooth 55 was extracted and distalization of tooth 16 was achieved using a removable appliance. Case 2: An 7-year-old male patient with bilateral EEM (16, 26). Tooth 26 was treated with an elastomeric separator; tooth 16, following premature loss of tooth 55, required distalization with a removable appliance. The patient later presented an eruption cyst in tooth 23 and required corrective orthodontic treatment. Case 3: An 7-year-old male patient with bilateral EEM (16, 26) and agenesis of teeth 35 and 45, successfully treated with elastomeric separators and currently undergoing corrective orthodontic treatment related to the agenesis. Conclusions: EEM may occur as an isolated condition or association with other dental developmental anomalies. Early treatment allows preservation of the arch perimeter, prevention of second premolar impaction, and reduction of the need for complex orthodontic procedures.