In previous chapters, we have reviewed the surgical and radiological evidence of the inferior alveolar nerve injury. When the overlapping of the mandibular canal and third molar is seen in the panoramic radiography, we assume there is a potential risk of injury of the inferior alveolar nerve. However, previous studies on CBCT have not made any statement of the degree of risk based on the CBCT findings. In this chapter we will propose a new classification of risk of the inferior alveolar nerve injury both in the panoramic radiography and CBCT.