Contact of Teeth With Blades of Macintosh Laryngoscope, McGrath MAC® Video Laryngoscope, and Pentax-AWS Airway Scope® During Tracheal Intubation: A Randomized Crossover Simulation Study.

Background Dental injury is a common complication during laryngoscopy for tracheal intubation. Due to the variety of laryngoscopes, the site of tooth contact with the laryngoscope blade might vary. The aim of this study was to investigate the difference in contact status of each individual tooth and various laryngoscope blades during orotracheal intubation, evaluated using a simulation study. Methods Fifteen anesthesiologists randomly attempted orotracheal intubation in two types of simulators (models A and B) using a Macintosh laryngoscope with #3 blade (ML) (Riester, Jungingen, Germany), McGrath MAC® video laryngoscope with #3 blade (MAC) (Medtronic, Covidien, Tokyo, Japan), and Pentax-AWS Airway Scope® with SL blade (AWS) (Nihon Koden, Tokyo, Japan), with colored articulating papers attached to the front and back of their blades. Following the procedure, the teeth of the simulators were examined for color transference, and the findings were recorded. Result The mean number (standard deviation) of contacted teeth per intubation maneuver when using the ML, MAC, and AWS were 4.3 (1.8), 3.9 (1.5), and 12.9 (2.7) in model A and 4.2 (2.3), 3.7 (1.3), and 13.2 (2.5) in model B. In both models, higher contact rates were seen for the left maxillary central incisor (>80%) and left mandibular central incisor (>60%), with no contact with the molars when using the ML and MAC. Use of the AWS resulted in higher contact rates with the central and lateral incisors bilaterally, both maxillary and mandibular (>80%), with bilateral maxillary premolars sometimes contacting the blade (>20%). Conclusion This simulation study suggested that during tracheal intubation using ML, MAC, and AWS, both the mandibular incisors and maxillary incisors may frequently come into contact with the laryngoscope blade. In addition, when using the AWS, more teeth come into contact with the blade compared to other laryngoscopes, and there is also the possibility of contact with the molars.