Final answer:
The literary device used in the passage is irony.
Step-by-step explanation:
In the passage, the literary device used is irony.
The dentist asks the narrator to open their mouth wide, which is a common instruction during a dental exam to inspect for decay. However, the dentist is not actually searching for decay but for gold teeth. This ironic situation creates a contrast between the expectation and the reality of the dentist's intentions.
This use of irony adds a layer of humor and a sense of deception to the passage, making it more engaging for the readers.