A 35-year-old patient complained about toothache on the left of his upper jaw that appears during eating, can be caused by thermal stimuli (especially by cold water) as well as by mechanical and chemical stimuli. The pain abates when the stimuli are eliminated. Objectively: there is a deep carious cavity with a narrow inlet within circumpulpar dentin. Probing of carious cavity floor is painful. Thermodiagnosis causes acute pain that abates immediately after stimulus elimination. Electric odontodiagnostics results - 15 microampere. Make a diagnosis: