Which of the following surfaces in a dental operatory should be covered by barriers?

Covering surfaces in a dental operatory with barriers is essential for infection control to prevent cross-contamination. The chosen answer encompasses multiple surfaces frequently encountered during dental procedures, which are prone to contamination by blood, saliva, or other infectious materials.

By applying barriers to the tray, light handle, keyboard, and chair, practitioners ensure that these high-touch surfaces remain protected between patients. The dental tray holds instruments that might become contaminated, the light handle is touched frequently by both the operator and possibly the assistant during treatments, the keyboard can also be contaminated through the operator's hands, and the chair is where the patient sits, making it susceptible to contamination as well.

In contrast, covering only the dental chair would neglect several other critical surfaces that are interacted with during procedures. Limiting coverage to a desk surface or operator's personal items does not address the primary areas that contribute to infection risk during dental treatments. Personal items may not be directly involved in patient care and might not need barrier protection in the same way that operatory equipment does. Therefore, proper barrier use as identified in the correct response is crucial for maintaining a safe and sterile environment in the dental practice.