The hypothesis of this study is that the velvet-soft PVC tube can advanced from the nasal cavity to the oral cavity through the posterior wall of the pharynx more smoothly than conventional PVC tube, thus reducing blockade of tube advancement, nasal/pharyngeal mucosal bleeding, and intubation time. In addition, investigators would like to compare the technique of nasal intubation using by connecting rubber suction catheter to PVC tube tip.
The purpose of the study is to find out the clinical effects that can be obtained during nasotracheal intubation when using velvet-soft PVC tube compared to conventional polyvinylchloride(=PVC) tube.