In this study, a Vickers indenter was pressed into glass-infiltrated alumina, yttria-stabilized zirconia (Y-TZP), and a ceria-stabilized zirconia/alumina nano composite (Ce-TZP/Al₂O₃ nano composite), using an indentation fracture method (IF method), and the effect on the calculated Vickers hardness, fracture toughness value, and indentation fracture load was examined to deduce the optimum conditions of the IF method for each material. As a result, the optimum indentation fracture load for the IF method was 10 and 20 kgf for glass-infiltrated alumina, and 20 and 30 kgf for Y-TZP. For the Ce-TZP/Al₂O₃ nano composite, cracks occurred at only 50 kgf; therefore, the only measured value was at 50 kgf. In addition, in the Ce-TZP/Al₂O₃ nano composite, a characteristic interpenetrated intragranular nano composite structure was observed, and its cracks led to an intergranular fracture, in which the cracks develop in the composite structure of zirconia and alumina particles in a zigzag manner.

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A system to measure length or location in coordinates was discussed using different object locations of two images obtained before and after parallel shifting of the optical axis in extreme close-up photography of dentition. This research is intended for the development of a stereo camera measurement system with simple, stable calibration methods. The system's measurement accuracy was verified by a Vanier caliper and dentition model, and its application to dimensional measurement by imaging was examined. The results showed that when the camera-caliper distance was set in the range of 350 to 550 mm, imaging measurements averaged 29.98 mm to the calipers' 30.00 mm length, for a mean error of -0.05%. However, the measurements showed a tendency to increase in proportion to the camera-caliper distance. The reason is thought to be that the presumed parameters set by the calibration contained measurement errors. This is a matter for future investigation.

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