We studied 411 children aged 3-10 years who were referred for dental treatment. 
They were randomly allocated to have inhalation conscious sedation with either 
sevoflurane/nitrous oxide mixture or nitrous oxide alone. Dental treatment was 
satisfactorily completed in 215/241 children who were given sevoflurane/nitrous 
oxide mixture (89%) compared with 89/170 who were given nitrous oxide alone 
(52%) (Chi square 70.3, p < 0.0001). All children remained conscious and 
responsive to verbal contact throughout the treatment and in the recovery room. 
No adverse side-effects were recorded in either group and there were no 
significant differences in oxygen saturation, heart rate, recovery profile, or 
time to discharge home between the groups. The study concluded that, for every 
100 children treated with sevoflurane/nitrous oxide mixture, 37 children would 
be saved a general anaesthetic if given combined sevoflurane and nitrous oxide 
mixture rather than nitrous oxide alone. The use of sevoflurane in low 
concentrations 0.1-0.3% to supplement nitrous oxide and oxygen for inhalation 
conscious sedation is safe, practical, and significantly more effective than 
nitrous oxide alone in children having dental treatment.