Aim and objective: Describe a case of sublingual displacement of a root of the lower third molar, as well as highlight the importance of using appropriate complementary imaging tests and provide the clinician with information on how to prevent and treat this complication. Background: The displacement of the lower third molar is an accidental event that can lead to serious complications, which is usually the cause of inadequate surgical technique. Case description: A 69-year-old man presented pain and trismus due to local infection 1 month after a tooth extraction. After a misdiagnosis of retained root and surgical exploration, a cone-beam computed tomography (CBCT) showed a displaced root into the sublingual tissues. A surgical procedure under local anesthesia was carried out to easily remove the displaced tooth root, which resulted in complete healing of soft tissues and disappearance of signs of local infection. Conclusion: The use of CBCT is essential for the identification and location of the dislocated tooth and the removal of the fragment, as it allows a three-dimensional assessment providing adequate surgical planning which resulted in complete remission of all symptoms. Clinical significance: Few reports have been published to describe this rare complication of dental extractions that support key points for proper management: (1) the use of three-dimensional imaging for proper evaluation and establishment of exact location; (2) careful surgical planning; (3) precise surgery. Successful tooth removal is the main goal of treatment, which usually results in control of associated signs and symptoms.