Scanning and electron microprobe analysis of metal-porcelain interface

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials

Background:

• The bond between porcelain and base metal alloys is crucial for the longevity of dental restorations.
• Understanding the interfacial chemistry is key to improving bonding and preventing failures.
• Previous research highlights the importance of oxide layer formation and its interaction with porcelain.

Purpose of the Study:

• To investigate the interfacial region between porcelain and base metal alloys.
• To identify the chemical composition and structural changes at the interface.
• To assess the impact of surface treatments like sandblasting on the oxide layer.

Main Methods:

• Scanning Electron Microscopy (SEM) for high-resolution imaging of the interface.
• Electron Microprobe Analysis (EMPA) for elemental composition analysis.
• Simulated firing procedures including sandblasting of oxidized metal samples.

Main Results:

• Formation of nickel oxide (NiO) and chromium oxide (Cr2O3) at the interface.
• Significant migration of NiO towards the porcelain layer was observed.
• Sandblasting indicated delamination of the oxide layer, revealing crystalline nickel and chromium.
• Analysis at the porcelain side detected NiO, Cr2O3, iron oxide, silicon (Si), potassium (K), chlorine (Cl), tin (Sn), and copper (Cu).

Conclusions:

• The study confirms the formation and migration of oxides (NiO, Cr2O3) at the porcelain-base metal alloy interface.
• Sandblasting can cause delamination of the oxide layer, suggesting potential weakening of the bond.
• The presence of various elements on the porcelain side indicates complex interfacial reactions influencing bond strength.