Final answer:
To ensure the patient is not dizzy or lightheaded after nitrous oxide sedation, it is recommended to have them sit upright in the dental chair for a few minutes before dismissing them.
Step-by-step explanation:
After completing treatment on a patient using nitrous oxide sedation, it is advisable to have the patient sit upright in the dental chair for a few minutes before dismissing them. This is done to ensure that the patient is not experiencing any dizziness or lightheadedness as a result of the sedation.