Which type of filtration is used in dental x-ray machines to reduce patient exposure to low-energy radiation?

The correct answer is B, which refers to the combination of inherent and added filtration in dental x-ray machines.

Inherent filtration is the filtration that occurs naturally in the x-ray tube itself due to the glass or metal envelope surrounding the tube. This type of filtration helps to remove some low-energy photons that do not contribute to the diagnostic quality of the x-ray image and only add to the patient's radiation dose.

Added filtration specifically involves additional materials, such as aluminum, placed in the beam path beyond the inherent filtration. This further filters out low-energy x-rays that are less likely to penetrate tissue and contribute to image clarity, while also lowering the overall dose of radiation the patient receives.

Using both types of filtration together is essential in modern dental x-ray machines, as it maximizes diagnostic quality while minimizing unnecessary radiation exposure to the patient. This practice adheres to the principles of radiation safety and patient care in dental radiography, ensuring that only the necessary amount of radiation is used to achieve clear images for diagnostic purposes.