[In vitro study on accuracy and repeatability of the T-Scan II system].

The T-Scan system has been used to analyze the distribution of occlusal loading forces, and occlusal contact variability. An enhanced version, the T-Scan II system, has been developed with clinical significance of its center of force. The T-Scan II system was also found to be clinically useful for measuring simultaneous occlusal contacts bilaterally. However, its improvement in accuracy and repeatability is still unknown. In the present study, the accuracy of time recordings, the liner relation between loaded forces and force recordings, the pressure sensitivity, and the variability of force recordings for repeated loadings, were investigated. The conclusions were as follows: 1. By regression analysis between the time and the time recording, the following equation was obtained: Y = 0.00357 + 0.9889 X R2 = 0.9964. The time recordings were proportion to the real time. 2. The force recordings were acceptably precise, especially for the moderately high level and default level, where a linear relation was observed. 3. The pressure sensitivity showed 6-61 g/cm2 for the high-4 level, 25-581 g/cm2 for the moderate-3 level, 56-1814 g/cm2 for the default level, and 146-3821 g/cm2 for the low-2 level. 4. The stability of force recordings for the repeated loadings was acceptable. A significant influence of repeated loading was found for the low-2 level; however, no significant difference was found between the repeated loadings, by post hoc analysis. On the contrary, the repetition of continuous loadings raised force recordings gradually, up to 120% at the fourth loading. The level of the force recordings stayed at the same level with no significant influence by repetition.