抄録
The following experiment was performed for the purpose of examining the relationbetween changes of dental casting alloys in vivo and results of immersion tests.
Five kinds of dental casting alloys were immersed in 0.05% HCI, 1% lactic acid and Ringer'ssolution, respectively. After one-week immersion tests, surface changes of each alloy were observedby SEM and the chemical composition was also analized by EPMA. And weight changeshad been measured for one month. The results are as follows.
1) Gold alloy and Ag-Pd-Cu-Au alloy showed very few changes in weight, surface andcomposition.
2) Ag-Sn-Zn alloy was obviously changed in weight, surface and composition, especiallyby HC1.
3) Low-chromium Ni-Cr (86 Ni-10 Cr) alloy showed remarkable weight loss in HCI andlactic acid, and also pitting corrosion in HCl. But in lactic acid, its surface was changed soslightly that only dendrite structures were observed. Any immersing solution, however, couldhardly change its chemical composition.
4) High-chromium Ni-Cr (70 Ni-19 Cr) alloy immersed in HC1 showed remarkable loss inweight. But in lactic acid, its weight change was fixed after one day. Ringer's solution causedlittle change in its weight. And its surface was severely changed by HCl.
