Effects of autoclave sterilization on the precision of 3D-printed surgical guides in implant dentistry

Three-dimensional (3D) printed surgical guides have improved the transfer of virtual implant planning to the clinical setting. However, autoclave sterilization may expose photopolymer resins to thermal and hygrometric stress, potentially affecting their dimensional stability. This study evaluated whether moist heat sterilization at 121 °C induces dimensional changes in 3D-printed surgical guides that could compromise implant placement accuracy. Ten identical maxillary models were used to fabricate standardized surgical guides based on a single digital plan. Five guides were sterilized in an autoclave at 121 °C (test group), while five were not sterilized (control group). The guides were produced from intraoral scanning and tomography of a randomly selected model and 3D printed from the same digital file. Linear and angular deviations between planned and obtained positions were measured through digital scanning and analyzed using GOM software. Statistical comparisons were performed using paired t-tests, with reference values from previous studies used to define acceptable precision margins. No statistically significant differences were observed between sterilized and non-sterilized guides for angular deviations within 4° (p = 1.000) and 2° (p = 0.203). Linear deviations also remained within acceptable limits, with no significant differences beyond 1 mm (p = 1.000) or 0.68 mm (p = 1.000). These findings indicate that autoclave sterilization at 121 °C does not produce clinically relevant distortions in the precision of 3D-printed surgical guides. However, further studies are needed to evaluate potential material fragility and the impact of alternative sterilization methods.