The Screw ([fig. 14]) is an instrument which on rare occasions is useful for the removal of deep seated roots.
After being used, instruments of every kind should be freed from all foreign matter and then carefully sterilised.
The next point which demands attention is the position of the operator and patient. The chair should be placed before a good light, and if a proper dental chair is not to hand an ordinary arm chair may be utilised; failing this, two ordinary chairs may be placed back to back, on one of which the left leg of the operator should be raised to form a rest for the patient’s head. The patient should be placed in such an unconstrained position as will allow the operator to exert all necessary movements with freedom.
Fig. 13.
Fig. 14.