The aim of this study is to evaluate the effect of valproate on the required dose of propofol for sedation in patients with mental retardation.

The intravenous sedation with propofol is very useful for patients with mental retardation and challenging behavior. However, it is very difficult to titrate the dose of propofol for maintaining the adequate sedation depth because of the difficulty of verbal communication with them. Most of them have a epilepsy and take antiepileptic drugs. Antiepileptic drugs are thought to influence on the effect of anesthetics. Valproate is reported to inhibit the metabolism of propofol. Therefore, we divide the patients into two groups : patients receiving valproate (valproate group), patients receiving no antiepileptic drugs (control group), and compare the required dose of propofol and the recovery time.

Inclusion Criteria:

1. Patients aged 16 or over
2. American Society of Anesthesiologists (ASA) physical status 1 or 2
3. The treatment of dental caries, endodontics, periodontics and prosthesis were planed
4. Participants had moderate or severe Mental Retardation, and were not completely cooperated with dental treatment

Exclusion Criteria:

1. Patients could communicate and cooperate with dental treatment, but used dental sedation for decrease of the anxiety and the fear about dental treatment or another reasons
2. Patients needed premedication and inhalational anesthetics
3. Patients had uncontrolled or sever medical condition

Patients with mental reterdation