Inhalation sedation has may advantageous properties that make it a suitable choice for sedation in pediatric, disabled and many patients, either alone or in conjunction with other agents. We need review of Guideline on use of nitrous oxide for dental patients that make minimizing complication of sedation for safe and effective sedation. Conventionally, nitric oxide is used for inhalation sedation, nowadays sevoflurane can also be used due to easily titratable for controllable effect and less failure of sedation. Recently sevoflurane can be used to provide sedation as a sole agent in air or oxygen or in combination with nitrous oxide in dentistry.