Objective  The aim of this study is to evaluate whether the treatment of ECC, performed in a single-session dental treatment under general anesthesia, can affect the quality of life of pediatric patients. It was assessed whether risks and discomforts involved in SSGA are outweighed by its effectiveness and reliability in improving oral health-related quality of life. Materials and Methods The quality of life that was assessed in this prospective study was oral health-related quality of life (OHRQL). Pediatric patients aged between 3 and 6 years with ECC undergoing dental treatment in SSGA were asked to fill in the Early Childhood Oral Health Impact Scale (ECOHIS) form both before and 1 month after the intervention. The data obtained were then statistically elaborated and analyzed to evaluate the actual significance of the differences found between the values before and after treatment and between the two sexes. Results Mean ECOHIS score before treatment was 30.58, following a large decrease after treatment, with a mean score of 2.94. Most parameters show a significant improvement between pre- and post-SSGA treatments, mainly those related to oral–dental pain, daytime irritability, and impact on family environment. Average ECOHIS scores for males and females are 31.72 and 29.76 before treatment and 3.55 and 2.52 1 month after treatment, respectively, showing no statistically significant differences. Conclusion The dental treatment of young children under SSGA is associated with considerable improvement in their OHRQL. It can be considered an effective and reliable way of managing cases that cannot be dealt with by alternative methods.