Symptoms of pulpitis manifest as painful eating, pain from hot and cold stimuli and nighttime pain. Pulpitis is an inflammatory reaction caused by bacterial infection of the dental nerve. Teeth are composed of enamel, dentin, bone and pulp tissue. The pulp tissue is located in the innermost layer of the tooth and is surrounded by hard dentin and bone. Once bacterial infection occurs, the inflammation is not drained, resulting in severe pain due to high pressure in the pulp chamber. The pain of pulpitis has typical symptoms. In the early stages of pulpitis, there is pain from eating, or from hot or cold stimuli, with some intervals of pain. The late stage of pulpitis is characterized by spontaneous pain, without any stimulation, and pain in the tooth. The intervals of pain become shorter and shorter, or the pain is constant. Pulpitis can also present with nighttime pain, difficulty sleeping or waking up from sleep in pain, which affects normal work and life. Pulpitis pain can also occur when the pain is not localized. Pain in one tooth may cause pain in the upper and lower jaw teeth on the same side and can radiate to the ear-temporal area and head. It does not usually radiate to the contralateral tooth. Therefore, the symptoms of pulpitis are severe pain, nighttime pain, increased pain from temperature stimulation, and pain that cannot be localized.