Surgical Management of Accidentally Displaced Mandibular Third Molar into the Pterygomandibular Space: A Case Report

Surgical removal of the mandibular third molar is a regular surgical procedure in dental clinics, and like all operations, it may have some complications, such as infection, bleeding, nerve injuries, trismus and so on. An accidentally displaced lower third molar is a relatively rare complication, but may cause severe tissue injury and medicolegal problems. As few papers and cases have been published on this topic, we report this case to remind dentists on ways to prevent and manage this complication. The patient, a 28-year-old male, had his right lower mandibular third molar extraction in January 2006. The dentist resected the crown and attempted to remove the root but found that it had suddenly disappeared from the socket. Assuming that the root had been suctioned out he closed the wound. The patient was not followed up regularly because he studied abroad. About 3 months later, the patient felt a foreign body sensation over his right throat, and visited a local hospital in Australia. He was told after a computed tomography (CT) scan that there was a root-like radio-opaque image in the pterygomandibular space. The patient came to our hospital for further examination and management in June 2006. We rechecked with both Panorex and CT and confirmed the location of the displaced root. Surgery for retrieving the displaced root was performed under general anesthesia by conventional method without difficulty, and the wound healed uneventfully except for a temporary numbness of the right tongue. This case reminds us that the best way to prevent a displaced mandibular third molar is to evaluate the condition of the tooth carefully preoperatively, select adequate instruments and technique, and take good care during extraction. If an accident does occur, dentists should decide whether to retrieve it immediately by themselves or refer the case to an oral and maxillofacial surgeon, and should not try to remove the displaced root without proper assurance. Localization with images and proper surgical methods are the keys to retrieving the displaced fragment successfully. When immediate retrieval is decided on, Panorex and occlusal view are useful in localizing the displaced fragment. When the fragment moves into a deeper space or the retrieval has been delayed for months, three-dimensional CT seems to be a better choice