Microprobe analysis of porcelain bonded to precious and non-precious metals
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This study was conducted to investigate whether ions from precious and non-precious metals migrate at the interface of porcelain and metals when the porcelain is being fired. If migration does indeed occur then which ions prevail and what is their role in establishing a bond between porcelain and metal. Three non-precious and one gold alloy were examined in this study. From each metal twenty samples were prepared which were divided into four groups of each five samples. A total of 100 castings were made. Each group was treated differently in order to establish the fact whether metal treatment can effect bonding. It was speculated what the specific treatment given to the metal prior to porcelain application would effect the elements at the surface which in turn effect the bonding of porcelain. Four different treatment techniques were used in this study. They are as follows: 1. degassing once: The samples in this group were degassed once at 1850 degrees Fahrenheit for five minutes under full vacuum (30 inches of mercury), washed in alcohol for five minutes and then porcelain was applied. 2. degassing twice: The metal samples in this group were degassed once at 1850 degrees Fahrenheit for five minutes under a full vacuum and then sand blasted and cleaned ultrasonically. The samples were washed and placed in alcohol for five minutes and then degassed for a second time prior to porcelain application. 3. Acid treatment: The metals in this group were degassed at 1850 degrees Fahrenheit under a full vacuum and then placed in acid (a mixture of Hel, H subscript 2 504, and HN03) for thirty minutes. After being cleaned, the porcelain was applied as in groups one and two. 4. High temperature treatment: The samples in this group were degassed at 1850 degrees Fahrenheit under a full vacuum. They were then removed and washed in alcohol. Afterwards, opaque porcelain was applied at 1900 degrees Fahrenheit (in contrast to 1850 in group one). The body porcelain was then applied and fired at 1700 degrees Fahrenheit, similar to all other groups. After porcelain was applied and fired, the samples were sectioned and examined by means of a scanning electron microscope with energy dispersive X-ray detector. Analysis of the graphs demonstrated the following: a) The type of ions observed at the interface were consistent, regardless of the treatment of the metal samples received prior to porcelain application. b) There is a small amount of penetration of Nickel from non-precious alloys and gold from Jelenco "0" to the side of porcelain. But it can be concluded that no significant ion exchange takes place at the interface of alloy and porcelain. c) There is a direct relation between the amount of concentration of Cr from metal side and Si in the porcelain side. d) Cromium and Nickel in non-precious alloys seem to play a role in bonding of porcelain.
PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact email@example.com.Partly colored photographs included.Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry (Prosthodontics), 1979.Bibliography: leaf 79.
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