Reply to Sayilir et al.

We have read the letter from Sayilir et al. reporting a case of temporomandibular joint (TMJ) dislocation that occurred in a patient undergoing upper endoscopy without sedation [1]. We appreciate their concerns about our previous publication in Endoscopy [2].

In our previous report, we showed that the incidence of endoscopy-related complications involving teeth or TMJ was not insignificant; when a traditional hard inflexible mouthpiece was used, the incidence in patients with and without sedation was 11.6 % and 0.9 %, respectively [1]. Although we did not experience the case of TMJ dislocation in our series, we thought TMJ dislocation might also occur more frequently in cases with sedation. Sedation can secondarily reduce muscle tone and not uncommonly cause paradoxical reactions associated with severe retching, which may contribute to TMJ injury [3] [4]. In the letter from Sayilir et al., however, they reported a case of TMJ dislocation in upper endoscopy without sedation. This case illustrates an important lesson, in that we should consider the possibility of postendoscopy TMJ-related adverse events even in patients without sedation. As they mentioned in the letter, the hard and inflexible nature of a traditional mouthpiece might be associated with this event. The new teeth-protecting mouthpiece (TPM; M1S, Seoul, Korea) has an elastic, flexible teeth-protecting component and can disperse the biting force located onto the teeth during endoscopy; it might also help in the prevention of TMJ dislocation.

We assume that there may be far more cases of endoscopy-related complications involving teeth or TMJ than currently reported worldwide. Despite the remarkable developments in gastrointestinal endoscopy, more interest and concern over the mouthpiece are required. The mouthpiece can be one important factor influencing patient-centered endoscopic examinations.

Competing interests: None

References

• 1 Sayilir A, Mevlut K, Sabite K. et al . Dislocation of the temporomandibular joint associated with upper endoscopy without sedation.  Endoscopy. 2009;  41 818
• 2 Min B H, Lee H, Jeong J S. et al . Comparison of a novel teeth-protecting mouthpiece with a traditional device in preventing endoscopy-related complications involving teeth or temporomandibular joint: a multicenter randomized trial.  Endoscopy. 2008;  40 472-477
• 3 Lacy P D, Lee J M, O’Morain C A. Temporomandibular joint dislocation: an unusual complication of upper gastrointestinal endoscopy.  Am J Gastroenterol. 2000;  95 3653-3654
• 4 Mangi Q, Ridgway R F, Ibrahim Z. et al . Dislocation of the mandible.  Surg Endosc. 2004;  18 554-556