Metal-ceramic interface evaluation of a gold-infiltrated alloy.
OBJECTIVE
The success of metal-ceramic systems partially depends on the formation of a stable bond between metal and porcelain. The purpose of this study was to investigate the porcelain/metal interface and the mechanism of interfacial bonding in a gold-infiltrated alloy (Captek).


METHODS
Captek specimens with feldspathic porcelain were evaluated by optical microscopy, scanning electron microscopy (SEM), electron probe microanalysis (EPMA), X-ray diffraction (XRD), and the Schwickerath crack initiation test for metal-ceramic bond compatibility. Specimens were processed with or without Capbond, a bonding agent. A traditional metal-ceramic alloy was also analyzed with microscopy for comparative purposes.


RESULTS
Optical and scanning electron micrographs of Captek specimens processed with Capbond revealed close adaptation of porcelain to the surface of the metal with sporadic nodules extending from the Captek surface. In contrast, the specimens of Captek without Capbond showed a much flatter porcelain/metal interface. Comparatively, the porcelain/metal interface of the traditional metal-ceramic crown showed greater surface roughness than the Captek specimens. No metal oxides were observed at the porcelain/metal interface of the Captek specimens with XRD. During the Schwickerath test, the Captek specimens permanently deformed, not allowing for crack initiation at the porcelain/metal interface.


CONCLUSIONS
Microscopy and XRD analysis showed that micromechanical interlocking is the primary mechanism of porcelain adherence to Captek metal. The use of Capbond prior to porcelain application to Captek results in gold nodules on the surface to aid retention. Existing metal-ceramic bond compatibility standardized tests are not sufficient for evaluating Captek, primarily due to the flexibility of the material.
Vasani
Rupal
R
Department of Prosthodontics, Marquette University School of Dentistry, Milwaukee, WI 53233, USA.
Kawashima
Isao
I
Ziebert
Gerald J
GJ
Berzins
David W
DW
D001840:Dental Bonding; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry*; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D006047:Gold Alloys / Q000737:chemistry*; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D018583:Pliability; D013314:Stress, Mechanical
D003764:Dental Materials; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain