What is the primary cause of tissue necrosis following local anesthetic injection?

Correct answer: A. Tissue ischemia from the vasoconstrictor

• A. Tissue necrosis after LA injection is primarily caused by tissue ischemia from the vasoconstrictor (epinephrine), especially in areas with end-arterial blood supply (nasopalatine foramen, greater palatine). Excessive concentration or volume can cause ischemic necrosis of the mucosa.
• B. The type of anesthetic is less important than the vasoconstrictor in causing necrosis.
• C. Poor injection technique can contribute (intravascular injection, excessive pressure) but ischemia from vasoconstrictor is the primary mechanism.
• D. The acidic pH of LA solutions can cause local tissue irritation but is not the primary cause of necrosis.