Types of dental alloys
1 Precious metal alloys
Precious metal alloys in dentistry, especially those based on gold, platinum, and silver, are characterized by their excellent corrosion resistance and biocompatibility. These alloys are traditionally valued for their long life and low wear, making them a preferred material for inlays, onlays, crowns, and bridges.
Gold alloys are particularly popular due to their workability and aesthetic qualities. They are easy to polish and match the natural tooth shade, provide an excellent fit, and minimize the risk of corrosion and plaque buildup.
Platinum alloys offer increased strength and hardness, making them ideal for thin restorations where maximum preservation of tooth structure is desired. Their use helps maintain the structural integrity of the restorative material while maintaining high aesthetics. Platinum: Platinum is a bluish-white metal with good ductility and malleability. Pure platinum can be used in dentistry because of its high melting point and good oral conditions. When used with gold, the alloy's hardness and elastic quality increase.
2 Non-precious metal alloys
Non-precious metal alloys, such as nickel-chromium and cobalt-chromium, offer a cost-effective alternative to precious metals. These alloys are known for their exceptional strength and hardness, making them ideal for structural applications in dentistry.
Nickel-chromium alloys are widely used in the manufacture of denture bases and metallic frameworks, although they may cause allergic reactions in a minority of patients.
Cobalt-chromium alloys are characterized by excellent corrosion resistance and biocompatibility, making them a preferred choice for patients with nickel allergies. A cobalt–chromium alloy can be used for prosthetic frames, implants, metal covers under a ceramic crown, or removable partial dentures (RPDs). Comparatively cheaper Co-Cr alloy-based metals are used extensively for dental prosthetics instead of exotic materials.
Titanium alloys have excellent biocompatibility, mechanical properties, and corrosion resistance. Their applications in the dental field are mainly reflected in dental implants, orthodontic correction, and maxillofacial restoration, which significantly improve the treatment effect.
Titanium-based alloys can be manufactured with complex shapes based on the individual patient's needs. Titanium-based oral implants are currently manufactured from commercially pure titanium or a Ti-6Al-4V alloy (90 wt% % titanium, 6 wt% % aluminum, 4 wt% % vanadium). These alloys have remarkable physical and mechanical properties; however, commercially pure titanium is the most popular choice due to its exceptional corrosion resistance and biocompatibility.
3 Ceramic-metal alloys
The combination of metal and ceramic in porcelain-to-metal alloys (Porcelain fused-to-metal, PFM) enables a perfect balance between aesthetic appearance and mechanical strength. These alloys are particularly valuable for anterior tooth restorations, where aesthetics are of utmost importance.
A porcelain-fused-to-metal (PFM) crown is also called a metal porcelain crown. It is a restoration made of low-melting porcelain and metal base material. It has the strength of metal and the beauty of porcelain. It can better restore the shape and function of the tooth. It is a permanent restoration with high strength, realistic appearance, stable color, smooth surface, not easy to wear, acid and alkali resistance, and good biocompatibility.