[Mechanical property and adaptability of super-plastic titanium alloy denture base]

The purpose of this study is to investigate the mechanical property and the adaptability of the upper complete denture bases made by superplastic forming of Ti-6A1-4V alloy plates which have various thicknesses. The strength of the denture base made by superplastic forming using the 0.55 mm thickness plate was lower than that of the base made by Co-Cr alloy casting in the standard form when loaded on the hard metal board. But by increasing the thickness by partial or full diffusion bonding of two Ti-6A1-4V alloy plates, the denture base became stronger than the Co-Cr alloy base. With resin occlusion rims, all the denture bases were reinforced. Moreover, when loaded on the mastermodel covered with rubber in the residual ridge and palate area, the difference of the strain between the thin and the thick bases became small. However, the strain of the thin base increased particularly when the base had a contact with the mastermodel on a small area in the palate. The superplastic forming denture bases revealed a high adaptability with the space less than 0.13 mm on the average between the base and the mastermodel. And increasing the thickness of the base prevented the worsening of the adaptability after curing resin for the denture.