Despite the laryngeal mask airway (LMA) has been widely used in anesthesia, its use is rare in the field of dentistry. Placing LMA in the oral cavity may interrupt dental treatment. However, there are some circumstances in which LMA is more advantageous than tracheal intubation for managing the airway. Especially, the reinforced LMA has a flexible tube shaft, rendering it more accessible for dental treatment. We report a case of dental treatment of a 3-year-old patient with hypoplastic left heart syndrome combined with pulmonary hypertension using reinforced LMA for airway management under general anesthesia. We also discuss the considerations of utilizing the reinforced LMA for dental treatment.