A Case of Horizontal Impaction of the Bilateral Mandibular Second and Third Molars

We report a case of horizontal impaction of the bilateral second and third molars, associated with a unilateral dentigerous cyst. A 20-year-old male complaining of an uncomfortable feeling in the mandibular left molar region was examined in our department. X-ray imaging revealed horizontal impaction of the bilateral mandibular second and third molars, and radiolucency around the crown of the mandibular left second molar. The bilateral mandibular and maxillary second and third molars were extracted and cystectomy was performed under general anesthesia.This patient had no previous medical history, exhibited no evident abnormality in jaw development or facial morphology, and a dentigerous cyst was present, suggesting that the impaction had been caused by local factors. The probable cause of the impaction was considered to be that tooth germs for the bilateral second molars were located at a low level and mesial inclination was pronounced, leading to impaired eruption, and that the left second molar was more deeply impacted than the right due to the dentigerous cyst. Combined use of orthodontic treatment and surgery was considered, but based on the patient's preferences regarding treatment, the decision was made to extract all the teeth at once and perform cystectomy under general anesthesia.