Dental trauma is one of the most common complications during laryngoscopy, especially by novice. As the chance of making direct contact with the teeth is decreased during laryngoscopy, the chance of applying direct pressure to the teeth is decreased, thus the injury by the blade also can be decreased. The purpose of this study was to determine the effectiveness of a modified Macintosh blade on reducing dental contact and the risk of dental trauma by novice laryngoscopists in anticipated difficult airway.

Sixty-six patients scheduled for elective surgery were divided into Easy group and Difficult group according to Wilson's risk sum score. Laryngoscopy was performed twice on each patient by novice, once with a regular Macintosh 3 blade and once with a blade in which the flange was partially removed (Callander modification). The distance between the flange of the blade and the upper incisors at glottic exposure was measured. We compared the blade-tooth distances and the chance of directly contacting the tooth between two blades.

The modified blade provided more distance than the regular Macintosh blade in both group (P < 0.001). It is also associated with decreased chance of directly contacting the teeth, especially in Difficult group (73.7% with regular blade vs 10.6% with the modified blade) (P < 0.001).

The modified Macintosh blade used in this study proved to be an effective device for novice laryngoscopists in reducing likelihood of dental injuries in anticipated difficult intubation.