Which of the following is a primary source of radiation exposure in dental settings?

X-ray machines are a primary source of radiation exposure in dental settings because they are specifically designed to produce radiation for diagnostic imaging purposes. In dentistry, X-rays are essential for diagnosing dental conditions, evaluating tooth and bone structures, and planning treatments. When used properly and under strict safety protocols, the benefits of X-rays in acquiring accurate diagnostic information outweigh the risks associated with radiation exposure.

In contrast, natural sunlight is a source of non-ionizing radiation and is not directly related to dental practices. Dental handpieces and ultrasonic scalers do not emit ionizing radiation, as they are primarily mechanical tools used for dental procedures such as drilling or cleaning. Thus, X-ray machines represent the unique source of ionizing radiation in the dental environment, necessitating proper training and safety measures to protect both patients and dental staff from potential radiation exposure.