An endoscopic mouthguard comprising a bite block comprising a generally annular body adapted to be inserted into the mouth of a patient so as to maintain the upper and lower teeth of the patient in a spaced apart relationship and define an endoscopic passage for introduction of an endoscope into the...http://www.google.es/patents/US7624736?utm_source=gb-gplus-sharePatente US7624736 - Oral oxygenating appliance
