Title: 0254 - Microstructural Analysis of Novel Presintered Milled and Cast CobaltChromium


Elie Daou (Presenter)
Lebanese University


Objectives: Evaluate Ceramic-alloys interface
Understand its impact on bond strength

Methods: Four ceramic–alloy specimens were sectioned (Ceramill-Sintron, Girobond-nb, Wirobond-99 and Ceramill-Zi). Morphology and chemical-analysis were monitored at the interface using SEM with energy dispersive X-ray spectroscopy (EDS).
Eight discs were added (n=2). Half of specimens (n=4) were considered as manufactured or cast. Other half (n=4) were ceramic-veneered (Vita-VM). All specimens (N=8) were subjected to XRD and AFM analysis to investigate the crystalline material structure. Microstructure of alloys (within the same group) was compared before and after ceramic-veneering, with opaque only, and after ceramic-firing protocol but without ceramic-layering.

Results: SEM images showed intimate bonding interface between alloys and veneering-porcelain. Some voids were detected within layered-ceramic. Line Scans gave an illustration of elements variations between porcelain and alloys. EDX quantification reported some differences between the manufacturers’ composition and products tested. XRD analysis showed no differences for NiCr and Zr, before and after porcelain veneering, or only after opaque. A net difference was found for CoCr Groups, milled and cast. This was confirmed for the CoCr Girobond after heat treatment without ceramic. Ceramic application produced significant change in crystallite size for CoCr cast only. A significant difference was found between heat-treatment and ceramic-application in this group.

Conclusions: SEM images showed intimate bonding interface between alloys and veneering-porcelain. Line Scans gave illustration of elements variations in each sample between porcelain and alloys.
No microstructural transformation was detected for NiCr and Zi after ceramic-layering. CoCr milled attained a stable and final crystal arrangement upon sintering. A phase transformation was reported for CoCr-cast after fire-heating without adding any ceramic.
Ceramill Si showed a promising more stable microstructure after sintering.


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Material/mean crystallite size As cast/milled With ceramic Heat treatment
Ceramill-Sintron 1.3285 1.330 1.427
Girobond-nb 1.731a 0.654a,b 1.753 b
Wirobond99 1.057 1.057  
Monoclinic (with/without ceramic)
Tetragonal (with/without ceramic)

  1,096c 1.779c  
Material/mean grain size As cast/milled With ceramic Heat treatment
Ceramill-Sintron 0.1497a,b 0.1177a 0.1133b
Girobond-nb 0.1124c 0.1597c,d 0.0935c,d
Wirobond99 0.0852e 0.152e  
Ceramill-Zi 0.1124f 0.0765f  

Student Presenter

This abstract is based on research that was funded entirely or partially by an outside source:
National Council for Scientific Research (CNRS)

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: No Financial Interest