Objective: This study aimed to evaluate the impact of storage temperature and duration on the dimensional stability and mechanical properties of 3D-printed surgical guides.

Materials and methods: Sixty surgical guides were designed using two software programs (3Shape and SMOP) and printed with NextDent SG resin. Specimens were stored at 2°C, 20°C, and 30°C (n = 10). Scans were performed at baseline and after 2, 4, and 6 weeks to assess dimensional stability by using root mean square (RMS) deviation. Additionally, 30 bar-shaped and 30 disk-shaped specimens were printed (n = 10) to evaluate flexural strength, flexural modulus, and hardness after 6 weeks of storage at the respective temperatures.

Results: Storage temperature had no significant effect on dimensional stability for 3Shape or SMOP. However, RMS values increased significantly from 2 to 6 weeks for both groups. In standardized mechanical specimens, storage temperature significantly affected flexural strength (p < 0.001) and flexural modulus (p = 0.018), but not Vickers hardness (p = 0.126). Flexural strength was highest at 30°C, while 2°C and 20°C did not differ significantly (p = 0.772). Flexural modulus was higher at 20°C than at 2°C (p = 0.038).

Conclusions: Storage temperature did not affect dimensional stability or hardness but influenced flexural properties in standardized specimens. Time-dependent dimensional changes were detected. Based on mechanical data, storage at 20°C or 30°C may be preferable to refrigeration for maintaining flexural performance.

Clinical significance: 3D-printed surgical guides demonstrated dimensional stability across varying storage temperatures, although time-dependent deviations were detected. Based on standardized mechanical specimens, refrigeration may not provide mechanical benefits compared with room-temperature storage. Therefore, room-temperature storage may be preferable when delayed use is expected, even in warmer climates.