Preoperative computed tomography imaging in the management of impacted mandibular third molars

The purpose of this study was to examine the role of preoperative computed tomography (CT) imaging of the inferior alveolar nerve (IAN) for patients at increased risk for nerve injury during mandibular third molar (M3) extraction.

To address the research purpose, the investigators enrolled a sample composed of subjects who presented for mandibular M3 extraction and had panoramic radiographic signs interpreted as being associated with an increased risk for inferior alveolar nerve injury. All subjects had preoperative CT imaging studies done to ascertain the position of the IAN with respect to M3. The predictor variable was the preoperative assessment of risk for IAN injury based on panoramic imaging. The outcome variable was the preoperative assessment of IAN injury risk after reviewing the CT studies. We documented the number of IAN injuries. Descriptive statistics were computed as indicated.

The sample consisted of 23 patients who had bilaterally impacted wisdom teeth. The sample's mean age was 26 +/- 6 years (range: 18-48 years); 69.6% of the patients were female. After reviewing the panoramic radiographic, 80.4% of M3s were classified as having an increased risk for IAN injury. Upon examining the CT imaging, 32.6% were classified as high risk for IAN injury. After reviewing all imaging studies, 71.7% of the teeth in the sample were extracted. Intraoperative IAN visualization occurred in 21.2% of the cases. At 1 week postoperative, 3 patients had dysesthesia (9.1%); none had a permanent nerve injury.

In this small series of patients, the additional information provided by 3-dimensional imaging changed the majority of patients from increased risk for nerve injury to low risk for nerve injury.