**Core Concept:** Pulpectomy is a dental procedure to remove the pulp tissue of a tooth, either for medical reasons (e.g., dental abscess, extensive caries) or preventive measures (e.g., in cases of developmental anomalies or high caries risk). In primary (also known as baby) molars, the procedure is called pulpectomy or pulpotomy.

**Why the Correct Answer is Right:** Dr. Charles Knowlton is credited with developing the complete pulpectomy technique for primary molars. This technique involves accessing the coronal pulp chamber, removing the coronal pulp tissue, cleaning the chamber, and filling it with a biocompatible material like calcium hydroxide paste or mineral trioxide aggregate (MTA). This procedure prevents future dental problems and ensures the tooth maintains its integrity until the permanent successor erupts, preserving oral health.

**Why Each Wrong Option is Incorrect:**

A. Dr. Horace Wells (teeth anesthesia) and Dr. Pierre Fauchard (dental anatomy) are famous for their work in dentistry, but not for developing pulpectomy techniques for primary molars.

B. Dr. Charles Knowlton's technique is specifically designed for primary molars, whereas Dr. William Giesman's technique is for permanent molars, which involves removing the entire root pulp and replacing it with a biocompatible material.

C. Dr. Alfred Wiltzius is known for his studies on dental pulp and pulp capping techniques but not for developing pulpectomy techniques for primary molars.

D. Dr. Harald Gjein's work is focused on pulpectomy techniques for permanent molars, using materials like calcium hydroxide or MTA, not for primary molars.

**Clinical Pearl:** The correct answer is Dr. Charles Knowlton, who developed the complete pulpectomy technique for primary molars, ensuring the tooth maintains its integrity and oral health until the permanent successor erupts.