Remove the upper cast and select a P.S.P. on the modeling compound in the same manner as the P.S.P. was selected on the last molar as described above.
Position the center point of the Bow Compass on the P.S.P. and apply an arc to intersect the arc from the A.S.P. as illustrated.
G. Alternate to the molar P.S.P. is a position on the Condylar Element of the Arcticulator, at its anterior intersection with the Condylar Shaft, Figure 8.
Position the center point of the Compass on this condylar posterior survey point (C.P.S.P.) and apply an arc to inter- sect the arc formed from the A.S.P.
H. Continue with Figure 7 or 8 by substituting the needle point for the graphite lead. Place the center point of the Bow Compass, still adjusted to the 4” radius, at the intersection of arcs on the Plastic Record Card (initial occlusal plane survey center).
Sweep the the needle point over the occlusal surfaces of the lower posterior teeth to see how the arc conforms to the existing occlusal plane. Shift this occlusal plane survey center (O.P.S.C.) on the long arc on Plastic Record Card, the A.S.P. line, until the most acceptable line and plane of occlusion is found.
To raise the line and plane of occlusion at the distal end, move the center point anterior to the arc intersection. To lower the line and plane of occlusion, move the point pos- terior of the intersection. By trial and retrial, in ideal survey center forming the most acceptable line and plane of occlu- sion will be located.
I. After thorough and considered study, this will be the best possible line and plane of occlusion for the lower posterior teeth to harmonize with all other factors. The center point of the Bow Compass is now pierced into this ideal O.P.S.C. on the Plastic Record Card and circled with pencil or ink for subsequent relocation. It may be advantageous to mark “R” (right) in the upper corner of the Plastic Record Card for identi cation, Figure 9.
J. A Plastic Record Card is then place over the dowels on the left side of the Card Index and marked “L”. Repeat the survey procedure, commencing with Step E, Figure 6.
The Scribing Knife, as furnished, is for placement into the Bow Compass for scribing or cutting plaster, compound or wax during the occlusal plane correction. The edge of the Scribing Knife may be sharpened to individual requirements as the edge supplied may not meet your preference.
This instruction has described the mechanical function of the Broadrick Occlusal Analyzer. We strongly urge the reader to refer to other reference material as well as classes devoted to the clinical application of this procedure in oc- clusal correction.