Beyond Initial Accuracy: Long-Term Aging and Clinical Stability of 3D-Printed Dental Resins in the Oral Environment

Occlusal devices, denture bases, and definitive restorations intended for long-term intraoral use are increasingly produced by three-dimensional (3D) printing, yet evidence for the durability of 3D-printed dental resins comes mostly from in vitro testing and short-term clinical follow-up.In the mouth, saliva, thermal variation, cyclic loading, chemical agents, and biofilm act concurrently over time, so initial accuracy and strength do not guarantee long-term clinical stability.This narrative review examines the long-term aging and clinical stability of 3D-printed dental resins by considering the chemical, physical, biological, and mechanical factors inherent to the oral environment and how material composition, printing parameters, post-processing, and clinical exposure influence long-term performance.The reviewed evidence indicates that aging is material-specific and multifactorial, affecting mechanical, physical, and esthetic properties depending on the formulation, manufacturing protocol, and patient-related conditions.Laboratory aging provides important insight into durability, but methodological heterogeneity and the incomplete simulation of the combined oral environment limit prediction of long-term clinical behavior.This review argues that the long-term success of 3D-printed dental resins should be judged not by their properties immediately after fabrication but by their ability to maintain structural, mechanical, dimensional, esthetic, and biological stability under the combined challenges of the oral cavity.Standardized multifactorial aging protocols and adequately powered longitudinal clinical studies are needed before recommending these materials for routine long-term use.