Objective To compare the reaction of children receiving computer-controlled local anesthetic delivery system（CCLADS） and a conventional syringe, and evaluate the efficacy of anesthesia and the reaction after treatment. Methods 30 children aged 4 to 9 years old, whose bilateral primary molars in the same jaw present similar lesions with similar treatment were included in the study. These bilateral primary molars were treated under local anesthesia in 2 separate visits with random use of either the CCLADS or conventional syringe. For the first visit, the first group received CCLADS anesthesia, in which buccal infiltration anesthesia was performed for maxillary primary molars, and periodontal ligament anesthesia was performed for mandibular primary molars. The second group received conventional anesthesia, in which buccal infiltration anesthesia was performed for both maxillary and mandibular primary molars. For the second visit, two groups used alternative anesthestic method. Pain behavior was observed and scored by modifiedchildren’s hospital of eastern ontario pain scale（MCHEOPS）. Pain perception was rated using facial image scale（FIS）. Results The MCHEOPS and FIS scores in 1 min injection of children with CCLADS were lower than children with conventional syringe（P0.05）. Conclusion In local anesthesia, CCLADS can reduce the injection pain caused by conventional syringe to a certain
extent.
