Currently known bite blocks or ET tube holder are mostly made of hard materials. It usually damage the soft tissues of the oral cavity. Their bite range is comparatively small due to their narrow product, thus causing a large tooth bite force, which might hurt the teeth of the patients. In addition, they are usually fixed on the lips by the adhesive tape , and easily hurts the lips while removing them.
There are also hospitals that use gauze as bite block. However it is soft with weaker anti-bite ability, and easy to detach from the tape and fall off after being damp.