Effect of cast orientation on occlusion Proper alignment of the occlusal plane with relation to the end controlling factors is of great importance for the cusp inclines and cusp pathways of a prosthetic reconstruction. The effect of various cast positions on cuspal inclines and pathways is demonstrated in the figure. Failure to use the face bow can lead to errors in occlusion of the denture. It is true that the errors may be small if the error in orientation of cast is small. Likewise, the errors produced by failure to use the face-bow would be negligible if all the interocclusal records were made precisely at the occlusal vertical relation and if zero degree teeth were used. However, if cusp teeth are used or if interocclusal records are made with the teeth out of contact so that the vertical separation of cast or dentures must be reduced on the articulator, the face bow record is essential. The face bow transfer allows a more accurate arc of closure on the articulator when the interocclusal records are removed and the articulator is closed. Zuckerman (1982) has stated that: 1. Superior/ inferior errors in location of hinge axis produces greater errors in occlusion than equivalent errors in posterior / anterior location.
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