 There is, however, a lack of the ideal sedative. Such drugs must, on the one hand, control the behavior of integral form, provide amnesia, minimizing physical discomfort, distress and pain, and, on the other, safeguard security, with minimal effect on the cardio-respiratory function, minimizing the occurrence of adverse events, as well as allowing the return of the patient to a State that allows high safely. The investigators thus performed this prospective study with the aim to assess the occurrence of adverse events during dental treatment and in the first 24 hours after sedation with midazolam, ketamine and sevoflurane in children aged four to six years. Our hypothesis was that no differences in adverse events among different association of drugs could be found. 