Impact of multiple steam sterilizations on the mechanical properties of 3D-printed surgical items.

This study investigates how repeated steam sterilization affects the mechanical properties of 3D-printed surgical items made from methacrylate-based Surgical Guide Resin. Unlike single-use instruments, reusable 3D-printed instruments undergo multiple sterilization cycles, which may compromise their durability. Cuboids produced using Digital Light Processing (DLP) were exposed to up to ten steam sterilization cycles (121 °C, 110 kPa), followed by drying. Mechanical tests included three-point bending, Shore D hardness, and microscopic analysis to assess elasticity, hardness, and structural changes. Initial sterilization cycles increased hardness and stiffness due to further polymer cross-linking. However, continued exposure led to visible surface damage, microcracks, and signs of polymer degradation. While bending strength remained relatively stable, cumulative effects ultimately reduced material integrity. These results raise concerns about the long-term reliability of multi-use 3D-printed surgical instruments. The findings suggest that current sterilization practices should be re-evaluated, especially for items intended for repeated use. Future research should focus on improving material resistance to minimize thermal degradation. This work offers critical insights into the safety and performance of reusable 3D-printed surgical items in both veterinary and human medical applications.