## 4 Discussion
The reduced mechanical performance often observed in CM restorations may be attributed to the inherent characteristics of the material preparation process and its molecular structure, particularly the manual mixing of mono-methacrylate resins, which makes it difficult to control air bubbles and porosity, thereby potentially compromising mechanical strength [35]. In contrast, the prefabricated blocks used for SM techniques benefit from industrial manufacturing methods that allow for higher monomer conversion and a denser polymer network, thereby minimizing porosity, voids, and polymerization shrinkage [2; 7]. The variability observed in 3D-printed restorations can be explained by findings from studies reporting that factors such as layer thickness, interlayer shrinkage, curing speed, intensity, angle, and printing direction influence the mechanical properties of 3D-printed materials [16; 37]. Additionally, the lower resistance of printed restorations has been linked to material shrinkage during and after construction, as well as to data manipulation in the STL file, where conversion and formatting steps may introduce changes [3]. To address this drawback associated with additive manufacturing, this study utilized digital light processing (DLP) technology, a highly precise technique in which resin polymerization occurs layer by layer in a cross-sectional manner. Each layer is individually polymerized under controlled conditions within the 3D printer, ensuring accurate reproduction of fine details while minimizing volumetric shrinkage [24]. Aging is a crucial factor that significantly impacts the performance of provisional restorations. Provisional resins are prone to water absorption, which can lead to the hydrolysis of monomers and the degradation of polymeric chains, ultimately compromising the material's mechanical properties. The strength of provisional restorations is highly influenced by water exposure, whether through storage in water, exposure to artificial saliva, or thermocycling [2]. According to the literature, 10,000 thermal cycles represent one year of clinical use; in the present study, half of the restorations underwent 5000 thermal cycles to simulate six months of clinical service [1; 38]. As the temperature increases, water uptake also rises, and the polarity of resin materials allows water to penetrate the matrix, leading to the leaching of monomers and additives. This process weakens the polymer chains, reduces intermolecular forces, promotes crack formation, and causes bulk swelling, all of which adversely impact the mechanical performance of the material. Thermal cycling was applied to half of the specimens before the fracture resistance test to assess these effects according to the manufacturing technique. As was consistent with previous findings [2; 5; 7; 25; 38], thermocycling demonstrated a statistically significant impact on temporary crowns and fixed partial dentures. Considering that vertical forces during mastication typically range between 10 N and 50 N, with occasional peaks reaching up to 900 N in the posterior regions, depending on various factors [27], the fracture resistance values obtained in this study after aging may not be adequate to ensure long-term clinical durability without limitations. In temporary fixed partial dentures, the combined effect of aging and manufacturing methods revealed that non-aged restorations manufactured using the SM technique initially exhibited higher fracture strength compared to those manufactured by AM and CM techniques. However, following aging, SM restorations showed a marked reduction, resulting in no significant difference among the three methods. These findings align with [PERSON] et al. [5], who observed that thermal cycling substantially diminished the flexural strength of SM restorations and eliminated the previously observed difference between the SM technique and the CM technique.