Advanced Dental Metallic Materials

The classification of metallic biomaterials is illustrated in detail, with special reference to dental casting alloys. The behavior of surface oxide films on metallic biomaterials in the human environment is taken into account. The requirements that metal implants must meet during the interaction between the human organism and the metal implant are discussed.

In the introduction, the structure and properties of titanium and titanium-based alloys relevant to dental applications are thoroughly examined. The osseointegration of titanium implants is examined from the standpoint of implant surface modification. Micro level surfaces and nanostructured surfaces are accurately considered using etching, surface Sol- Gel Processing (SSP), and a variety of processes and materials. Here are two instances of our expertise: (i) Plasma spraying hydroxide apatite coatings on Cp-Titanium Grade 2 surfaces; and (ii) Corrosion on the surface of a Titanium substrate caused by an alkaline and heat treatment combination. The topic of dental implant antimicrobial surface engineering is briefly discussed at the end of the chapter.

Cobalt–Chromium (Co–Cr) alloys are used in dental prosthetics for removable partial denture restorations, complete cast metal-ceramic restorations, dental bridges, crowns, and implants. Their mechanical properties, high strength and hardness, combined with good corrosion and tarnish resistance provide them with the necessary biocompatibility and performance for extensive use. The chapter presents a brief overview of the physico-chemical properties and the processing options of Co–Cr alloys. Using modern dental laboratory processing techniques allows for the fabrication of dental prostheses by conventional casting, milling and additive manufacturing. The main principles and workflow of these processes are given, highlighting key aspects for producing dental prosthetic restorations using Co–Cr alloys.

Beginning with the Shape Memory Mechanism, two types of Shape Memory Al-loys (SMA) are considered: (i) Nickel-Titanium Alloys and (ii) Copper-based Alloys. SMA orthodontic appliance NiTi Orthodontic Wire is thoroughly discussed. In the section Expetise Examples, we highlight: (1) Comparison of commercially available NiTi orthodontic wires, (2) Experimentation with continuous casting of nitinol, and (3) Microstructure, mechanical characteristics, and corrosion behavior of NiTi and CuAlNi alloys made by continuous casting. Ni-Ti wire corrosion and biocompatibility are specifically addressed. We highlight (I) the surface characterisation of NiTi orthodontic archwires following mechanical loading simulation in CACO₂-2 cell culture and (II) the deposition of an atomic layer of a TiO₂ on Ni–Ti SMAs for corrosion prevention in a simulated body fluid.

Well-known for their established reputation in restorative dentistry, gold alloys offer an excellent combination of strength, biocompatibility, and aesthetic appeal. Combined with other noble and base metals like palladium, silver, platinum, copper and zinc, these dental alloys exhibit enhanced mechanical properties while maintaining their inherent corrosion resistance and superior biocompatibility. Dental practitioners and patients benefit from these high quality materials, as they provide reliable tooth preparations and provide for durable long-lasting restorations. As research and development introduces cheaper contemporary materials, they are being compared to gold dental alloys, which have been highly suited for clinical use for decades. Gold dental alloys are preserving their high standard status in the dental community, especially for long-span bridges and for patients with bruxism. Their development has diminished in recent times due to their high prices, while conventional and redesigned gold dental alloys described in the chapter still represent a leading choice for patients susceptible to allergies, and for patients requiring or requesting the best for a lasting dental restoration with high aesthetics.

This chapter describes a low-temperature technique for soldering and brazing bioceramics to biometals in dentistry that uses reactive multi-layer nanofoils as a local heat source. Dental applications of Al-Au nano-multilayered foil are shown, along with examples of expertise. The authors present numerical modeling and CFD investigation of exothermic processes in Al-Au nanofoils.