Physical Stimuli include which of the following?

• A. Thermal changes from hot and cold or electrical energy created by metals in contact with the tooth
• B. A very thin layer of debris on dentin
• C. A dental liner placed at the pulpal floor
• D. A varnish made of natural resins

Answer: (A)

Physical stimuli are changes in the tooth’s environment that can provoke a sensory response, such as heat or cold and electrical energy produced in the mouth. The option that mentions thermal changes from hot and cold and electrical energy created by metals in contact with the tooth describes exactly these kinds of physical inputs the tooth can sense.

The other choices describe things that are not stimuli themselves: a thin layer of debris on dentin is just a surface condition, a dental liner is a protective material placed on the pulpal floor, and a varnish is a protective coating. None of these represent actual physical energy input to trigger a response.