Second molar eruption disturbances in borderline extraction orthodontic patients.

Introduction: Nonextraction treatment is associated with a greater prevalence of third molar impactions, whereas data on second molars are lacking. This study investigated whether there is a difference in the prevalence of second molar eruption disturbances when crowding is treated with or without extractions.

Methods: Patients were grouped by maxillary and mandibular crowding, including mild crowding (<5 mm) without extractions, borderline crowding (5-9 mm) without extractions, and borderline crowding with extractions.