Bite force measurement on intercuspal clenching in normal subjects using the pressure sensitive sheet “Dental Prescale” showed that larger bite forces were applied to the posterior teeth than to the anterior teeth. In this study, an experimental model revealed that the even thickness of the pressure sensitive sheet was one of the influential factors in this characteristic distribution.
The experimental model consisted of 14 steel ball-bearings, used as substitutes for the dentition, and a glass slab which were respectively mounted in the maxillary and mandibular elements of a semiadjustable articulator. Three kinds of loading conditions were determined and applied to the upper member with an Instron-type testing machine; then contact forces were compared with the Occluzer FPD-703. Firstly, the upper member was removed from the articulator and the pressure sensitive sheet was loaded directly. Secondly, the condylar elements of the articulator were locked through centric latches, and thirdly, the condylar elements were not locked.
The direct load distributed contact forces almost equally to each steel ball. On the contrary, the load with locked condylar balls distributed larger contact forces to the posterior steel ball-bearings than to the anterior ones. However, the unlocked load showed a similar distribution to the direct load.