- Patients directed to conscious sedation under midazolam because they cannot be approached for more than a very brief examination, or following failure to treat under inhalation sedation (50% N2O/O2), or following poor cooperation during treatment under inhalation sedation (poor cooperation is defined as a score of 3 or more on the French modified version of the Venham scale), or following good cooperation during short and simple treatment under inhalation sedation but in need of more complex rehabilitation.