A 38-year-old man presents to your clinic with a chief complaint of severe pain in his lower left jaw for two days. He describes the pain as a throbbing ache that sometimes occurs spontaneously. Cold drinks make the pain much worse, and it lingers for several minutes after the stimulus is removed. The pain was severe enough to wake him from sleep last night. He has been taking ibuprofen every six hours, which provides temporary and partial relief. His past dental history includes several amalgam fillings placed many years ago. He is medically fit with no known drug allergies and takes no regular medications.