Ectopic Impaction of a Mandibular Third Molar Below the Mandibular Notch: A Case Report

Ectopic impaction of a mandibular third molar in the mandibular notch or coronoid process is an uncommon clinical finding.We report a rare case of an ectopically impacted mandibular third molar located below the mandibular notch, accompanied by a residual root of the mandibular second molar that was considered to have migrated to the same region.A 60-year-old male presented with pain in the left mandible and trismus.Clinical examination revealed diffuse swelling extending from the left cheek to the submandibular region, with a maximal mouth opening of approximately 10 mm.Tenderness was noted in the buccal gingiva of the left mandibular molar area.Computed tomography demonstrated an ectopically impacted mandibular third molar near the left mandibular notch, surrounded by a radiolucent lesion.An adjacent radiopaque structure, located anterior to the impacted tooth, was suspected to be a residual root fragment.Based on the clinical and radiographic findings, a diagnosis of chronic sclerosing osteomyelitis of the left mandible associated with the ectopically impacted third molar was established, and anti-inflammatory therapy was initiated.Following resolution of the acute inflammatory symptoms, surgical treatment was performed under general anesthesia via an intraoral approach.The ectopically impacted mandibular third molar and the associated cystic lesion were successfully removed.