Thermoplastic materials such as polyamides (nylon), acetal resins, epoxy resins, polystyrene, polycarbonate resins, polyurethane and acrylic thermoplastic resins were introduced in dentistry as an alternative to classic resins, which have major disadvantages such as the toxicity of the residual monomer, awkward wrapping system and difficult processing.
Part of the book: Thermoplastic Elastomers
Alloys are used in various areas of dentistry. The field of dental alloys is a very extensive one, encompassing both the materials themselves as well as the manufacturing methods, which are constantly developing. Our chapter focuses on corrosion and biocompatibility assessment, using various methods. At present there is no perfect dental alloy. Superalloys for dental use are not yet available, and only few studies concerning the new generation of superalloy candidates for medical applications have recently been developed, with promising results.
Part of the book: Superalloys
Alloys are used in various areas of dentistry, but mainly in prosthetics. Their properties, behavior, and corrosion resistance are of great importance for the success of the prosthetic treatment. Among the investigations used for assessing dental alloys, in this chapter, we focus on metallographic observation, scanning electron microscopy, and energy-dispersive X-ray spectroscopy and present the ways we investigated several types of dental alloys. We obtained important data concerning their structure and corrosion potential that could explain certain shortcomings which appeared after luting of the fixed partial dentures.
Part of the book: Micro and Nanotechnologies for Biotechnology
Acrylic resins dominated dentures technology for several decades. Due to their many disadvantages, new classes of resins, which promise better quality, constantly appear. Mechanical properties of acrylic resins, including fracture behaviour, water absorption and mechanical strength degradation caused by the exposure to saliva of classical heat-cured acrylic resins compared to alternative urethane-based light-cured resins, were carried out. The allergy potential of acrylic resins was evaluated by in vivo and in vitro tests. New choices of resins, like thermoplastic injected resins, light-cured or milled high-performance polymers, with better properties compared to acrylics, suitable for dental applications are being presented.
Part of the book: Acrylic Polymers in Healthcare
Laser welding permits joining various types of pieces, made of similar or different alloys, as titanium-based alloys, CoCr alloys, and even AuPd alloys. Laser welding is best suited to weld titanium alloys because they have higher rates of laser beam absorption and lower thermal conductivity compared to other dental casting alloys. Compared to micro pulse welding, laser welding is superior, obtaining the welding cord being faster and easier. The success of the welding procedure depends on the operator’s dexterity and the choice of the welding parameters. Selecting the best combination of pulse energy, pulse duration, and peak power for each welding step is decisive.
Part of the book: Superalloys for Industry Applications
Titanium alloys are considered to be the most advanced materials for orthopedic implants due to the favorable combination of mechanical properties, low density, tissue tolerance, high strength-to-weight ratio, good resistance to corrosion by body fluids, biocompatibility, low density, nonmagnetic properties, and the ability to join with the bone. This is the reason why we decided to assess the resistance of two titanium alloys currently used for orthopedic implants, namely, Ti6Al7Nb and Ti6Al4V, as reference, to cyclic fatigue by dynamic tests with crevice corrosion stimulation. According to the results obtained, the examined electrochemical quantities, the visual and SEM observations, and EDX analysis reveal better corrosion behavior of the prostheses made of Ti6Al4V—anodized series compared to prostheses made of Ti6Al7Nb. The further comparison of two explanted proximal modules, made of Ti6Al7Nb and Ti6Al4V, to the same type of prostheses evaluated by cyclic fatigue dynamic tests with crevice corrosion stimulation reveals that there are significant similarities, in particular with regard to the electrolyte diffusion, deposition of products and corrosion. Cation extraction tests which were carried out for Ti6Al7Nb prostheses that have undergone particular surface treatments show significant differences depending on the surface treatment and demonstrate that orthopedic implant materials are not “inert.”
Part of the book: Engineering Steels and High Entropy-Alloys