A 4-year-old with Duchenne muscular dystrophy requires pulp therapy on a mandibular second primary molar. Which local anesthetic technique is most predictable?

Correct answer: B. Inferior alveolar nerve block

• A. An intrapapillary injection anesthetizes soft tissue for rubber dam clamp placement or matrix seating. It provides no pulpal anesthesia.
• B. CORRECT. For PULP therapy on a mandibular PRIMARY SECOND MOLAR, the INFERIOR ALVEOLAR NERVE BLOCK is the technique of choice. Even in young children, the cortical plate over the second primary molar and the developing first permanent molar region is thick enough that infiltration is unreliable for pulpal anesthesia. Because pulpotomy/pulpectomy requires profound anesthesia of the pulp tissue itself, the block is the predictable choice.
• C. Topical agents penetrate only 2-3 mm of mucosa and cannot anesthetize pulp.
• D. Buccal infiltration alone gives reliable PULPAL anesthesia in the mandible only for primary incisors, canines and often the first primary molar in very young children, where the bone is thin and porous. It becomes unreliable at the second primary molar, and it is not adequate for pulp therapy there.

Note: The DMD consideration is not the injection but everything around it: progressive proximal muscle weakness, declining respiratory reserve, cardiomyopathy, risk of MALIGNANT HYPERTHERMIA-like reactions and rhabdomyolysis with volatile agents and succinylcholine, and macroglossia with poor airway protection. Local anesthesia with careful positioning is far safer than general anesthesia here.