INSTRUMENTS FOR HOLDING MOUTH OPEN
When performing extractions of mandibular teeth, it is necessary to support the mandible to prevent stress on the temporomandibular joints (TMJs) By having the patient’s jaw supported on a bite block, the joints wilt be protected. The bite block is just what the name implies (Fig. 6·29, A and 8). It is a rubber block on which the patient can rest the teeth. The patient opens the mouth to a comfortably wide position, and the rubber bite block is inserted, which holds the mouth in the desired position. Should the surgeon need the mouth to open wider the patient must open widely and the bife block must be positioned more to the posterior of the mouth.
The side-action mouth prop or Molt mouth prop (Fig. 6-3) can be used by the operator to open the mouth wider if necessary, This mouth prop has a ratchet-type action opening the mouth wider as the handle is closed. This type of mouth prop should be used with-caution, because great pressure can be applied to the teeth and TMJ, and injury may occur with injudicious use. This type of mouth prop is useful in patients who are deeply sedated.
Whenever a bite block or side-action mouth prop is used, the surgeon should take care to avoid opening the mouth too widely, because it may cause stress on the jaw joint. Occasionally, this may result in stretch injury to the joint, necessitating additional treatment. When long procedures are being performed it is a good idea to periodically remove the prop and allow the patient to move the jaw and rest the muscles for a short time.