The aim of this clinical trial was to investigate the efficacy of 38% silver diamine fluoride (SDF) in the arrestment of dentine caries in primary molars of preschool children. The time required for treatment, anxiety, adverse events, parental aesthetic perception and oral health related to quality of life (OHRQoL) were also assessed. Sixty, 3–5 years old children, were assigned randomly to SDF test group or atraumatic restorative treatment (ART) control group. The ICDAS criteria determined the presence of caries and its activity. The treatment time was recorded, and the child’s anxiety was evaluated using the facial image scale before and after treatment. The caregivers were asked about any adverse events and the questions regarding esthetic perception were addressed to them. The OHRQoL was evaluated through the A-ECOHIS questionnaire before and 3 months after treatment. The overall success rates of SDF and ART after 12 months were 86.7% and 80%, respectively. There was no significant difference in arrestment of caries between SDF and ART (P value > 0.05). The time required to treat with SDF was significantly shorter (p < 0.001). The percentage of adverse events revealed no significant difference (p=0.604).