A 33-years-old female pateint with cerebral palsy showing spastic quardriplegia and severe mental retardation was scheduled for dental implant restorations. Before implant surgery we had to take implant CT. But, because of her involuntary motion and communication difficulty, sedation was needed in order to take CT. After 8 hour NPO, propofol infusion sedation with TCI (target controlled infusion) system was administered. The propofol blood concentration of the patient was maintained 2-3 ${mu}$/ml to keep deep sedation to prevent uncontolled movement. During sedation, we monitored ECG, pulse oximetry, blood pressure, capnometry for patient safety. Oxygen was administered via nasal prong for preventing hypoxemia and to keep airway during sedation some bands were applied to lift mandible. Total duration was 20 minutes for taking CT, and she was discharged from hospital after 30 minute rest without complication.