The 3-D tensile and compressive forces exerted on a tooth were measured in vivo during function using a force-measuring device including a piezoelectric transducer. The device was mounted on the maxillary left second molar of a healthy male subject; the subject tooth had been endodontically treated and prepared for metal abutment and a crown. The 3-D forces were expressed as a vector of the coordinates based on the Frankfort horizontal (x-y) and sagittal (y-z) planes. The device captured the sequential changes in the forces. The directions of the forces changed during not only chewing a caramel or a peanut but also maximum voluntary clenching (MVC). As the magnitudes of the force increased during both MVC and caramel chewing (CaC), the force vector tended to correspond to the direction of the palatal root, medially and posteriorly. The compressive forces during MVC and caramel and peanut chewing were 173.29+/-15.32, 146.3+/-14.7 and 57.7+/-35.7 N, respectively. The force vector during MVC was directed from the crown to the root medially at an angle of 10.27+/-1.00 degrees from the y-z plane and posteriorly at an angle of 3.18+/-0.85 degrees from the x-z plane to the perpendicular line of the F-H plane. There were significant differences in the behaviour of the compressive forces between clenching and chewing. The tensile force was recorded during CaC, not peanut chewing.

A method was developed to detect fluorescence intensity signals from single molecules diffusing freely in a capillary cell. A unique optical system based on a spherical mirror was designed to enable quantitative detection of the fluorescence intensity. Furthermore, "flow-and-stop" control of the sample can extend the observation time of single molecules to several seconds, which is more than 1000 times longer than the observation time available using a typical confocal method. We used this method to scrutinize the fluorescence time series of the labeled cytochrome c in the unfolded state. Time series analyses of the trajectories based on local equilibrium state analysis revealed dynamically differing substates on a millisecond time scale. This system presents a new avenue for experimental characterization of the protein-folding energy landscape.

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Abstract:The purpose of this research was to evaluate tooth movement in six degrees of freedom under occlusal force loading. The right side upper first premolar movement of an adult volunteer without any signs or symptoms of periodontal disease was studied. A small occlusal table mounted on a force transducer was clipped between the upper and lower dentition. Occlusal force was applied to the buccal cusp, palatal cusp or central fossa of the first premolar and also to the right side canine aspect by clenching this occlusal table.The right side first premolar movement relative to the left side first premolar was measured by means of a highresolution six degrees of freedom motion detector. The three-dimensional shape of the first premolar was measured with following methods. A 3-D digitizer with a touch sensor probe was used to measure the coronal part of a cast stone model of the tooth. Computerized tomography data were used to obtain the root shape of the tooth. These movement and configuration data were combined to perform computer graphics analysis of the three-dimensional tooth movements. The range and direction of tooth movement were varied by altering the position and amplitude of occlusal force loading. Since the magnitude of the tooth movements was relatively small, we adapted the screw axis (helical axis) concept to emphasize tooth movement on the computer graphics representations.