Mechanical Principles of Elevators used in Dentistry

Elevators are stainless steel instrument used in dentistry during tooth extraction. There are three mechanical principles which are applied to increase their mechanical advantage.

a) Lever Principle
b) Wedge Principle
c) Wheel and Axle Principle

Lever Principle: Try to remember your physics classes. You must have studied about types of levers. So the elevators used here are lever of first class, which has fulcrum in between the load and effort. The effort arm is longer than the load arm to increase the mechanical advantage. While extracting tooth controlled force is delivered in predetermined direction.

Wedge Principle: Remember the shape of "wedges" used in conservative dentistry. In this principle elevators having wedge shaped tips are used to split, expand or elevate the alveolar bone prior to tooth extraction.

Wheel and Axle Principle: It is modified form of lever. Here the effort is applied at circumference of the wheel which in turn rotates the axle of the instrument so that weight (tooth) can be lifted.

Hope, now you know how your elevators work, but I don't think elevators of your building work likewise!!