Intubation for pediatric patients is frequently performed with an uncuffed endotracheal tube (ETT), which may result in an incomplete tracheal seal, resulting in gas leakage (leak). The purpose of this study was to assess the effect of (1) mouth opening and (2) throat pack placement in sealing and/or minimizing this leak to an acceptable level while providing adequate tidal volumes in mechanically ventilated patients. This prospective study of 2- to 6-year-olds undergoing general anesthesia with nasal intubation for dental procedures in the New York University–Lutheran Medical Center operating room was conducted between March 2015 and October 2015. Three sequential tidal volume (V_T) measurements were recorded: postintubation with the neck extended, with mouth opened, and after throat pack placement. Twenty-five subjects were included in the analyses. For subjects in whom no leak was detected, only throat pack placement statistically improved V_T. This is in marked contrast to numerically large, statistically significant effects, relative to baseline, for mouth opening (±23.2 mL, p < .009, 21% increase from baseline) and throat pack placement (±46 mL, p < .009, 41% increase from baseline) when a leak was detected. In children 2–6 years of age, nasal intubation with uncuffed ETTs that have incomplete tracheal seal have improved V_T with mouth opening and throat pack placement. This finding suggests that the intubation procedure is a process that extends through positioning, mouth opening, and throat pack placement.