Pharmacology, Anesthesia and Pain Management
This domain tests drug selection, maximum doses, and management of the failed mandibular block.
Local anesthetics
- Lidocaine 2% with 1:100,000 epinephrine: 36 mg per 1.8 mL cartridge; maximum about 4.4-7 mg/kg, up to 300-500 mg.
- Articaine 4% with 1:100,000 epinephrine: 72 mg per cartridge; fastest onset, metabolized by plasma esterases; some evidence of increased paresthesia risk after inferior alveolar block.
- Mepivacaine 3% plain for short appointments; bupivacaine 0.5% with 1:200,000 for long postoperative analgesia.
- Prilocaine carries a methemoglobinemia risk.
The inflamed pulp problem
Inferior alveolar nerve block fails in a high proportion of mandibular molars with irreversible pulpitis because of altered nerve membrane potential and inflammation. Supplemental techniques: buccal infiltration with articaine, intraligamentary injection (about 0.2 mL per root), intraosseous injection, Gow-Gates or Vazirani-Akinosi alternatives.
Preemptive and postoperative analgesia
Ibuprofen 400-600 mg with or without acetaminophen 1000 mg, taken 30-60 minutes before treatment, reduces postoperative pain. Opioids are not indicated for routine endodontic pain.
Antibiotics
Amoxicillin 500 mg three times daily for 7 days when systemic signs are present; metronidazole added for spreading infections; in penicillin allergy, azithromycin or clindamycin (with caution because of Clostridioides difficile). Never for irreversible pulpitis alone.
Worked example
A mandibular molar with irreversible pulpitis; the block gives only lip numbness and the tooth remains painful. Give a supplemental intraligamentary or intraosseous injection, then complete treatment at the same visit.
Traps
Exceeding the maximum dose by counting cartridges loosely; failing to aspirate; prescribing antibiotics for a painful pulp; using prilocaine in pregnancy or anemia.