Which injection is needed in addition to maxillary buccal injections to numb the lingual roots of tooth #3?

To numb the lingual roots of tooth #3, which is typically the first maxillary molar, the greater palatine nerve block is an effective choice. This injection targets the palatal tissues and innervates the posterior part of the maxilla, providing adequate anesthesia for the lingual aspects of the maxillary molars.

While other options, such as the middle superior alveolar nerve and the anterior superior alveolar nerve, provide anesthesia to the more anterior and sometimes the occlusal surfaces of maxillary teeth, they do not effectively anesthetize the lingual aspects and roots of tooth #3. The infraorbital nerve injection focuses more on the anterior teeth and does not adequately cover the lingual areas needed for this particular tooth.

The greater palatine nerve block, therefore, is necessary in conjunction with the maxillary buccal injections to ensure complete anesthesia of the affected area, specifically addressing the lingual roots and associated tissues.