Abstract: An instrument particularly adapted for use in dentistry but capable of a wide variety of other applications and including a divider-caliper type instrument typically having two members of equal length and substantially corresponding configuration pivotally secured to one another wherein opposite ends of each member is defined by different sized points. A scale format is formed on an exposed surface on at least one of the members and is based on the golden proportion of 1 to 0.618. Accordingly, a plurality of scale settings are disposed in predetermined spaced apart relation to one another based upon formulized calculations resulting in use of the caliper instrument in dental applications including direct oral procedures, dental laboratory techniques, cephalometric analyses as well as aiding in the establishment of arch form, tooth size and outline form as well as cusp-fossa proportions and the accurate and simple placement of developmental grooves.

Abstract: A proportional divider comprises a reference index located between a pair of variable indices and a sectionalized threaded spindle having opposite end sections with reverse threads and of different pitches in a ratio approximating 1 to 0.618. Each spindle section threadingly engages a support for one of the variable indices whereby rotation of the spindle simultaneously adjusts the distances between each variable index and the reference, the distances being maintained in said ratio which is known as the "golden proportion". In one form of divider, the supports for the variable indices are retained for movement along a straight track, the reference and variable indices being portions of pointers extending perpendicularly to the track, the reference pointer being fixed and the variable pointers being mounted on said supports. A plurality of interchangeable reference pointers and variable pointers provide versatility to the divider.