Physically and neurologically handicapped pediatric dental patients are often a challenge to treat and may require the use of pharmacological agents for behavior modification. The purpose of this study was to investigate the safety, in terms of vital sign changes and complications, and the effectiveness, in terms of behavioral changes, of two dosages of oral midazolam as a conscious sedative agent for this unique population. Participating in this study were 31 patients of Texas Scottish Rite Hospital for Children, who were uncooperative (as rated on the Frankl scale) at a previous dental appointment. The patients, 3-18 years old, were randomly selected to receive one of the two dosage regimens; Group A received 0.3 mg/kg oral midazolam and Group B received 0.5 mg/kg. Physiologic parameters and behavior were recorded throughout the appointment and overall safety and success were determined. Although clinically insignificant, Group A's pulse rates 20 min into treatment were significantly higher than at baseline or treatment start, and oxygen saturations were lower during treatment than at baseline and start of treatment. Intratreatment systolic and diastolic blood pressures and pulse rates of Group B were significantly higher than the baseline figures; however, these changes were not clinically significant. No clinical or postoperative complications were noted for either dosage. The regimen of 0.3 mg/kg of oral midazolam was successful 75% of the time, and the regimen of 0.5 mg/kg of oral midazolam was successful 60% of the time in providing adequate sedation to allow operative treatment to be safely and efficiently performed.(ABSTRACT TRUNCATED AT 250 WORDS)