Bilayered zirconia (Vita In-Ceram庐 YZ) veneer (Vita VM庐9) blocks were manufactured. Raman analyses were performed using two protocols: (1) single spectra, line scans and images on a sectioned and polished specimen and (2) in depth line scans on unprepared specimen. Single spectra, images and line scans provide information about the crystalline phases, their distribution and the existence of a possible diffusion at the Y-TZP/VM庐9 interface, respectively. The elemental distribution of zirconium (Zr) and silicon (Si) around this interface were investigated using energy dispersive X-ray spectroscopy (EDS).
Raman single spectra embodied a unique spectrum (crystalline) on Y-TZP and two spectra (crystalline and amorphous) on VM庐9; these spectra were clearly distinguished. Raman line scans showed a series of transition spectra across the interface from VM庐9 to Y-TZP. It emphasized an interdiffusion zone, which was estimated at a maximum of 2 microns, found on 2d Raman images and confirmed by EDS. The elemental distribution with EDS showed a mutual diffusion of Zr and Si and was mainly dominated by Si diffusion in Y-TZP.
Confocal Raman microscopy highlights an interdiffusion zone at the zirconia-feldspathic ceramic interface. The elemental transition layer is estimated and is supported by EDS analysis as a coupling technique.