Nanotechnology has emerged as a transformative force in modern dentistry, offering unprecedented advancements in both endodontics and prosthodontics through the manipulation of materials at the nanoscale. This review synthesizes current knowledge on nanotechnology applications in these fields, evaluating their impact on treatment outcomes, material performance, and patient care while critically addressing associated challenges and future research directions. In endodontics, nanoparticles have revolutionized root canal therapy by enhancing disinfection efficacy through superior penetration into dentinal tubules, significantly reducing reinfection risks and improving antimicrobial action. Nanomaterial-enhanced sealers and obturating materials exhibit improved mechanical properties, including increased strength, fracture resistance, and adhesion, thereby extending treatment durability. Furthermore, nanotechnology facilitates pulp tissue regeneration via targeted drug delivery systems and scaffolds that support stem cell differentiation and tissue revitalization. In prosthodontics, nanomaterials have dramatically improved the aesthetic and functional quality of dental restorations by closely mimicking the natural optical and structural properties of teeth while enhancing mechanical strength, wear resistance, and longevity. The integration of nanoparticles into prosthodontic materials has also resulted in superior surface hardness, modulus of elasticity, and reduced polymerization shrinkage, alongside antibacterial properties and controlled therapeutic agent delivery that promote oral health and patient comfort. Despite these promising advancements, significant challenges remain, including concerns regarding long-term biocompatibility, cytotoxicity, systemic toxicity, and environmental impact of nanomaterials. The lack of standardized regulatory frameworks and comprehensive clinical safety data further complicates their widespread clinical adoption. Future research must prioritize rigorous preclinical and clinical investigations to establish robust safety profiles, develop application-specific regulatory guidelines, and advance innovative technologies such as smart stimuli-responsive materials, personalized nanotherapies, and nanorobotic interventions. Sustained interdisciplinary collaboration among researchers, clinicians, and regulatory authorities will be essential to fully harness the transformative potential of nanotechnology in dentistry while ensuring patient safety and improved therapeutic outcomes.