In order to determine the vertical dimension of occlusion utilizing the edentulous patient's perception of mandibular position, we have been developing a new method and apparatus. The aim of this study was to clarify how the position of occlusal support influence the perception of mandibular position of ten edentulous subjects when the constant method is used.
The testing apparatus was composed of an upper occlusal rim, a lower base plate with three metallic cylinders and nine different height occlusal blocks at intervals of 1 mm. The subject was asked to indicate whether each height inserted 10 times at random was felt to be high, low, or comfortable. The upper and lower limens that elicited a response of high or low in 50 percent of the trials were calculated. The zone between these limens was the comfortable occlusal zone (COZ). In this study, the records of COZ were performed under the three following conditions ; A: one occlusal support at the incisal region, B: three occlusal supports at the incisal and bilateral first molar regions, and C: two occlusal supports at the molar regions.
The COZ obtained in posterior contacts (C) was significantly higher in position (p<0.01) than those obtained in anterior contact (A, B). It was suggested that the position of occlusal support should be standardized when the perception of mandibular position is used to determine the vertical dimension in complete denture construction.