to produce heat. Electrical pulp test: Electric pulp testing (EPT) has been available for over a century and is used by dentists worldwide. It is used to determine the health of the pulp and pulp-related pain. EPT is based on the stimulation of sensory nerves in the pulp. It does not provide information on vascular supply to the pulp. The probe tip of the test device is placed directly onto the tooth surface and an electrical stimulus is produced. This stimulus causes an ionic change across the neural membrane, inducing an action potential in the myelinated nerves. The threshold of pain is determined by increasing the voltage. A tingling sensation is felt once the voltage reaches the pain threshold. This threshold level varies between patients, and is affected by factors such as age, pain perception, tooth surface conduction and resistance. The requirements of an EPT are appropriate application method, careful interpretation of the results, and an appropriate stimulus. EPT must be done with tooth isolation and conduction media. Key factors in pulp testing are the enamel and dentine thickness, and the number of nerve fibers in the underlying the pulp. EPT is not used in patients with orthodontic bands or crowned teeth, as the current may be conducted to adjacent teeth, resulting in false-positive responses. Pulp nerve fibers also respond to lower current intensities and only a small number of pulpal nerves are required to create responses when electrical stimulation is applied. This means that EPT may result in false-positive responses in teeth with pulpal necrosis. Furthermore, as pulpal and periodontal nerve thresholds overlap, the periodontal nerves may give a false indication of tooth sensibility. Possible explanations for false-positives include: Response caused by conduction of the current because of periodontal or gingival issues Breakdown products associated with pulp necrosis may be able to conduct electric current next to infected and hypersensitive pulp tissue Inflamed pulp tissue may still be present Metallic restorations or orthodontic gear are still present Studies have indicated that there is little correlation between histopathological status of the pulp and clinical information. A negative EPT response showed localized necrosis in 25.7% of cases and 72% of cases. Thus, 97.7% of cases with a negative response to EPT indicated that a root canal treatment should be carried out. Test cavity: The preparation of a test cavity involves cutting into the dentine of a tooth to determine whether the