A designated controlled area must be identified around each x-ray machine in the dental workplace. From which point is this distance measured?

The correct measurement point for establishing a designated controlled area around an x-ray machine is from the machine head. This is because the machine head is where the x-ray beam is emitted, and therefore, it represents the source of radiation. Measuring from this point ensures that the designated controlled area adequately protects both staff and patients by delineating the zone where radiation exposure might occur during the operation of the x-ray equipment.

By defining the controlled area starting at the machine head, safety protocols can be effectively implemented to minimize radiation exposure in adjacent areas. This measurement is critical for maintaining compliance with safety standards and regulations in dental practices. It also helps in establishing a safe working environment by ensuring that only authorized personnel are allowed within the designated area during x-ray procedures.

Other reference points like the dental chair, exposure button, or machine control panel are not suitable for this purpose because they do not represent the actual point of radiation emission. Consequently, they do not provide accurate information about where to establish protective boundaries.