For 2 days a man has been suffering from spontaneous nocturnal pain attacks in the area of his tooth 25. The pain radiates along the branches of the trigeminal nerve and alternates with brief painless intervals. Objectively, the mesial surface of tooth 25 has a deep carious cavity within the parapulpar dentin. Probing of the cavity floor and percussion are painful. Thermal stimulation of tooth 25 provokes a pain attack. What diagnosis can be made in this case?