## 1 Introduction
This technology is especially advantageous for producing restorations with intricate geometries or undercuts, where conventional manufacturing methods may be less effective. Three-dimensional printing, a significant innovation in additive manufacturing, enables the layer-by-layer fabrication of restorations using techniques such as fused deposition modeling (FDM), digital light processing (DLP), and stereolithography (SLA). DLP is particularly notable for its speed and precision, making it well-suited for dental applications. This technique allows for the production of highly detailed and durable prostheses without relying on traditional impression materials or extensive manual processing, thereby enhancing efficiency in clinical practice [12]. Despite these advantages, research on the mechanical properties of 3D-printed materials has yielded inconsistent and sometimes contradictory findings [13; 14; 15]. The mechanical behavior of 3D-printed restorations is affected by several parameters, including raw material composition, light-curing conditions, layer thickness, laser type and efficiency, printing orientation, and post-processing procedures, all of which significantly influence the final restoration's mechanical properties [16]. Provisional restorative materials must retain their mechanical properties throughout their clinical lifespan, as exposure to intraoral conditions can significantly affect their performance. The storage conditions of these materials have been shown to impact their mechanical properties, particularly water absorption. PMMA are susceptible to water uptake due to their linear polymer structure and polarity, making them prone to molecular infiltration. Additionally, the air bubbles introduced during manual mixing can further increase the susceptibility of chairside-fabricated PMMAs to water absorption, potentially leading to hydrolysis and a decline in mechanical properties. In contrast, dimethacrylate-based resins, with their highly cross-linked structure, demonstrate lower water absorption and are less prone to air entrapment when dispensed from cartridges. However, despite their improved resistance, dimethacrylates still absorb water over time, which can cause them to weaken and become more brittle after prolonged exposure to humid environments [5; 7]. Several studies [13; 14; 17; 18] have compared additive manufacturing techniques with subtractive and conventional manufacturing techniques in terms of the physical and mechanical properties of provisional crown and fixed partial denture materials. Research on fracture resistance has examined both aged and non-aged crowns and fixed partial dentures. However, there is a lack of studies investigating the impact of aging on restorations fabricated using different manufacturing techniques. Therefore, this study aims to evaluate this effect on crowns and fixed partial dentures. The purpose of this in vitro study was to compare the fracture resistance of provisional crowns and fixed partial dentures manufactured using three different techniques: conventional manufacturing (CM), subtractive manufacturing (SM), and additive manufacturing (AM). Additionally, the effect of thermal aging on fracture resistance was evaluated. The null hypothesis was that the manufacturing technique and thermal aging process would not significantly affect the fracture resistance of the provisional restorations.