抄録
Materials in oral appliances used to protect teeth during tracheal intubation were compared and considered. Hard materials have strength but require time to prepare. Hard material with a thickness of 0.8mm （0.8H） scored the highest in compatibility and in the compression test. However, it is not considered suitable for patients with poor motor skills or unstable teeth, due to difficulty in insertion/removal, and constriction. Soft materials can be more easily constructed for an appliance but have lower strength. In addition, soft material with a thickness of 2.0mm was extremely loose and interference with intubation operation was of concern. Soft and hard materials with a thickness of 2.3mm （2.3SH） and soft material with a thickness of 3.0mm had good compatibility. Insertion and removal were simple. In consideration of visibility during intubation, 2.3SH was more suitable.
From the above results, it is suggested that oral appliances used to protect the teeth during tracheal intubation should be made of 0.8H or 2.3SH. In particular, 2.3SH is considered applicable to all cases, although it is expensive．
