A prospective non-randomised study to compare oral trauma from laryngoscope versus laryngeal mask insertion

Prospective studies evaluating the incidence of dental injuries in anaesthesia are scarce or absent. The aim of this study was to compare the incidence of oral trauma in patients submitted to laryngoscopy and orotracheal intubation with those anaesthetized with a laryngeal mask.

This observational study was performed in the University Hospital, with blind evaluation. We evaluated 121 patients older than 18 years old who were submitted to elective surgery under general anaesthesia. Patients were excluded if they were pregnant, underwent surgery of the mouth or required nasal intubation. Laryngoscopy and orotracheal tube were used in 70 patients and laryngeal mask in 51. Twelve to 24 h before anaesthesia and after surgery, all patients underwent a detailed oral examination performed by an anaesthesiology and a senior dentist, both blind to anaesthetic management details. Injuries of the teeth were diagnosed based on WHO's classification system modified by Andreasen.

Oral injuries were found in 84.1% of the patients after laryngoscopy and 19.6% after laryngeal mask insertion (P < 0.001). Corresponding values for teeth injuries were, respectively, 38.6% and 2.0% (P < 0.001). The great majority were enamel fractures of the maxillary incisors. This means that patients submitted to laryngoscopy had a significantly higher incidence of oral injuries compared with those having laryngeal mask insertion (unadjusted OR 21, 99; CI 0.95: 8.55-56.55).

Minor oral trauma is significantly more frequent after endotracheal intubation than after use of the laryngeal mask. This is true for injuries of the teeth, inferior lip and tongue. Further studies are needed to evaluate on a long-term basis the clinical relevance of the dental injuries we found.