Children should not be sedated without an trained sedation nurse, an anesthesiologist on site, and a full cardiac monitor. There are pediatric dentists who use "light" or conscious sedation, but there should always be a trained, licensed medical professional on hand whose sole responsibility is the administration of medication, and monitoring of vital signs, until the patient's vital signs have returned to pre-anesthesia levels, they are awake, and have held down clear liquids.
i was a sedation nurse, and was responsible for sedating children for radiologic procedures (usually MRIs). When we sedated, we followed all the rules and had an anesthesiologist on site. I interviewed with a dentist once, but they had no anesthesiologist on site, so I refused the job. I also would never allow myself, or any of my family to be sedated without verifying who would be monitoring us.