Forces exerted on upper and lower teeth during intubation: a randomized crossover trial comparing indirect videolaryngoscopy to direct laryngoscopy

During endotracheal intubation the anesthesiologist uses a laryngoscope blade
to distract the tongue to achieve the best view of the glottis opening, thereby
avoiding using the maxillary incisors as a fulcrum to lever the soft tissues
upwards. Using the maxillary incisors as a fulcrum may otherwise result in
dental trauma. It is obvious that contact with teeth and - even worse - the
incidence of accidental dental trauma, is directly related to the difficulty of
the intubation.
Indirect videolaryngoscopy has proven advantageous over direct laryngoscopy
using a classic Macintosh blade, for improved viewing of the glottis, with
subsequent more successful intubations, and a shorter effective airway time
both in patients with normal and difficult airways. Previously, it has been
demonstrated that the forces exerted by the anesthesiologist on the patient*s
maxillary incisors are reduced when using a videolaryngoscope, compared with a
classic Macintosh laryngoscope. However, only one type of videolaryngoscope was
used. Also only forces exerted on upper teeth were registered.

Measuring the forces exerted on upper en lower teeth during classic (direct)
and (indirect) (video)laryngoscopy.

Randomized, cross-over trial

Minimally, the study will be conducted completely while the patient is under
general anesthesia. The risk of dental injury may be slightly increased, as two
devices are being placed in the patients mouth.