Broken needles are one of the accidents that may occur during dental treatment. Most occur during inferior alveolar block anesthesia, but sometimes the injection needle breaks and is lost in deep soft tissue during infiltration anesthesia. We report a case in which a dental needle broke during local anesthesia and strayed into the infratemporal fossa. A 29-year-old woman was referred to our department to search for the lost needle on the day. The injection needle could not be found near the extraction socket by oral examination. In the panoramic radiograph, a linear radiopaque object was found from the posterior upper part of the left maxillary tooth extraction cavity to the posterior upper part. CT revealed that the broken injection needle was located in the infratemporal fossa along the maxillary bone. On the day of the incident, the needle was removed under general anesthesia. With reference to the three-dimensional CT image, the lower end of the needle could be found in the soft tissue over the periosteum, and was removed. The removed object was a 30G needle with a length of 21mm that had broken at the base and also had bent near the center. The patient was discharged on the 7th postoperative day and was followed up for 2 months. The postoperative course was uneventful.
