A 29-year-old patient complains of acute paroxysmal pain in the upper jaw on the left, that gets worse during having cold food and irradiates into the ear and temple. A year ago she experienced intense pain in the 27 the tooth but didn't consult a dentist. Three days ago there was the second attack of pain. Objectively: there is a deep carious cavity in the 27th tooth, interconnecting with the tooth cavity. Probing the open area causes acute pain. What is the most likely diagnosis?