Final answer:
The anatomical landmark used to identify the maxillary cuspid periapical film in dental radiography is the Maxillary sinus, which is located in the maxillary bone above the molar and premolar teeth.
Step-by-step explanation:
In relation to dental radiography, the anatomical landmark used to identify the maxillary cuspid periapical film is the Maxillary sinus. The maxillary bone forms the upper jaw and much of the hard palate, and the Maxillary sinus is located in this bone. It is a large cavity that lies above the molar and premolar teeth. This sinus can be seen in dental periapical films and it serves as a critical landmark when analyzing maxillary cuspids on radiographs.