The diagnosis of incomplete cusp fractures has primarily relied on patient symptoms, which sometimes results in late treatment approaches. The transillumination of tooth structure by a fiber-optic light source can be considered an important adjunct tool in the diagnosis of incomplete cusp fractures before they reach their end stages. Furthermore, transilluminated teeth can be documented by intraoral photography, using a two-handed technique by holding a transillumination device and an intraoral camera simultaneously, with the resulting images shared with the patient. This simple, painless, and noninvasive technique can be incorporated easily into daily practice to evaluate high-risk sites, regardless of patient symptoms. This article reviews incomplete cusp fractures, explains how to detect them using transillumination and intraoral photography, and addresses how to discuss the results with patients.