Hot tooth is commonly seen with:
A hot tooth refers to a tooth with irreversible pulpitis with moderate to severe pain and such tooth are difficult to anesthetize. The hot tooth is more commonly encountered with mandibular first molars. Clinically patients with hot tooth sip a glass of ice water to control the pain and there will be sensitivity to extreme temperatures. Pain may radiate to ear, temple and even to the maxillary arch but such pain will never cross the midline. The hot tooth usually has a failure of an inferior alveolar nerve block between 44% to 81%.
Theory to explain the difficulty in anesthetizing the hot tooth:
Dental pulp contain c-fibers that harbors a special class of sodium channels known as tetrodotoxin-sensitive sodium channels (TTX). But during pulpal inflammation, there is a shift in the expression from tetrodotoxin-sensitive sodium channels to tetrodotoxin-resistant sodium channels (TTXr) which are more resistant to the local anesthetic lidocaine. Hence hot tooth are challenging to anesthetize.
Management of anesthesia for Hot tooth:
Bupivacaine is found to be more effective in blocking the TTXr channels. Along with this supplementary intra-ligamental or intraosseous injection or intra-pulpal anesthesia can be helpful.