Perception of vertical dimension.

Ten edentulous adults were investigated to learn more about the preferred vertical dimension of occlusion (PVDO) and the comfortable zone. A screw jack device was employed, using the forced-choice and external approach methods. The dimensional discrimination ability of each subject was assessed at the mean PVDO, and at points 3 mm above and below it. For each subject, both the forced-choice and external approach methods gave a mean PVDO value which was reasonably constant. The comfortable zone widths were less consistent. In all but two of the subjects the mean PVDO values appeared consistent with a clinically acceptable occlusal vertical dimension. No relationship was found between the dimensional discrimination ability of the subjects and their definition of PVDO and comfortable zone.