The clinical effectiveness of mandibular block anesthesia was compared to that of buccal infiltration anesthesia. A total of eighty patients three to nine years old was selected with identical bilateral lesions. The anesthetic used was mepacaine HCL 2 percent. The treatments performed were restorations, pulpotomies, and extractions. Child behavior and pain reaction were recorded and rated at certain intervals of treatment, using the Frankl behavioral scale and the SEM scale. The Eland color scale was also used in another sample of twenty patients to determine which type of anesthesia was more acceptable to children. The paired t-test was used to compare results. Buccal infiltration anesthesia was found to be as effective as block anesthesia in all situations, except when pulpotomies were performed in the mandibular second primary molar, where it proved to be unreliable regardless of age. Block anesthesia was significantly more painful than buccal infiltration anesthesia, and behavior of children three through five years old sometimes turned negative following the block injection.