The newly revised and expanded second edition provides an updated overview of advances in dental gold alloys and gold nanoparticles for biomedical applications. Building on the foundation of the first edition, the book integrates the latest research, innovations, and clinical perspectives. Dental gold alloys remain a benchmark material in restorative dentistry, offering a desirable combination of mechanical strength, ductility, elasticity, and long-term chemical stability in the oral environment. In parallel, research on gold nanoparticles has rapidly evolved, establishing them as multifunctional biomaterials for cellular imaging, biosensing, drug delivery, tumour immunotherapy, and photothermal therapy. This edition places special emphasis on synthesis methods, surface modification strategies, and bioconjugation techniques for fine-tuning nanoparticle size, shape, and stability in complex biological systems. It also incorporates recent findings on how exposure routes, surface chemistry, and nanoparticle coatings influence biodistribution, therapeutic performance, and toxicity. The book combines literature reviews with up-to-date experimental results and case studies, regulatory aspects and global gold nanoparticle manufacturers and the characteristics of their products. This work offers a valuable resource for practicing scientists and engineers working in the field of various types of gold-based biomaterials.