Final answer:
The selection of the appropriate kilovoltage for dental films is primarily influenced by the tissue density, as it affects the penetration of the X-rays and the quality of the radiographic image.
Step-by-step explanation:
The selection of the appropriate kilovoltage for dental films is influenced by tissue density (D). Tissue density affects the penetration of the X-rays and therefore the quality of the radiographic image obtained. The kilovoltage setting determines the quality and energy of the X-ray beam, with higher kilovoltages allowing the beam to penetrate denser tissues more effectively. When setting up a dental X-ray, it is important to consider the density of the tissues being imaged to ensure that the resulting images are of sufficient quality to show the necessary detail. Factors such as line voltage fluctuation (A) can also affect the quality of the X-ray images, but the primary consideration related to kilovoltage is how it must be adjusted depending on tissue density.