The purpose of this study was to examine the effect of heating on the physical properties of four types of premixed calcium silicate-based root canal sealers. Endoseal MTA, Well-Root ST, EndoSequence BC Sealer, EndoSequence BC Sealer HiFlow, and AH Plus (epoxy resin root canal sealer) were heated at 100°C for 1 min, and changes in setting time, flow, and film thickness were evaluated in accordance with ISO 6876:2012 standards. In addition, pH measurement and scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analyses of the set materials were performed. All root canal sealers heated at 100°C showed significant decreases in setting time and flow, particularly Endoseal MTA. In addition, the film thickness of Endoseal MTA increased significantly after heating at 100°C. The pH and SEM/EDS results were not affected by heating. Heating calcium silicate-based root canal sealers accelerated setting time, decreased flow, and increased film thickness. However, the degree of these changes varied among the products. The present findings indicate that heat-induced changes in the physical properties of calcium silicate-based root canal sealers could adversely affect the quality of warm vertical condensation technique.
This paper describes comparative analyses of time-efficient multi-arm assembly using a task board for a belt drive unit. The task board was used for the World Robot Summit (WRS) 2018 competition. From the viewpoint of using multiple arms, handling multiple parts simultaneously, and representing assembly both by robot systems and by human subjects, this paper introduces the set that shows only the contact condition between the arm and the part to arrange the time series data easily. Based on this analysis, there is a significant difference in the whole work time between the robot systems and the human subjects. One of the reasons is the difference in the usage of multiple arms. It will be important for robot systems to utilize multiple arms simultaneously to realize the time-efficient multi-arm assembly.