Final answer:
The basic principles described are for the periapical technique used in dental radiography, where the film packet and tooth's long axis must be parallel, and the central ray is perpendicular to both.
Step-by-step explanation:
The basic principles described are for the periapical technique, which is used in dental radiography. In this technique, the film packet and the long axis of the tooth being radiographed must be parallel to each other. Additionally, the central ray of the x-ray beam is directed perpendicular to both the film packet and the tooth. This helps in obtaining a clear image of the entire tooth including the crown, root, and surrounding structures, which is essential for diagnosing various dental conditions. The periapical technique is one of several intraoral techniques used to produce images that can reveal problems such as cavities, bone loss, and hidden dental structures, such as wisdom teeth.