Clinical Implications of Sterilization Methods Applied to 3D-Printed Implant Surgical Guides: An In Vitro Study

This in vitro study evaluated how 3 sterilization methods-autoclaving, ethylene oxide (EO) gas, and hydrogen peroxide gas plasma-affect the mechanical, physical, and dimensional properties of 3-dimensional (3D) printed implant surgical guides. These techniques are widely used in dental practice but differ in mechanism and limitations.

Twenty specimens were fabricated using a digital light processing printer and divided into 4 groups (n = 5): non-sterilized control, autoclaving (121 °C, 15 minutes), EO gas (55 °C, 60 minutes), and hydrogen peroxide gas plasma (<57 °C, 18 minutes). Mechanical tests evaluated flexural strength, modulus, and Shore D hardness while translucency and dimensional stability were also assessed. Shape deviation and implant positioning accuracy were compared before and after sterilization. Data were analyzed with one-way analysis of variance and Tukey's post hoc test.

All sterilized groups maintained internal fit deviations within clinically acceptable tolerance (±120 μm), showing no significant differences in overall dimensional accuracy. Implant placement precision was preserved, with implant-tooth distances ≥2 mm. EO sterilization significantly increased the flexural strength (122.49 ± 10.10 MPa) and modulus (3477 ± 161 MPa) compared with controls whereas autoclaving showed the lowest strength (92.40 ± 15.06 MPa). Shore D hardness exceeded 90 HS in all groups, with autoclaving producing the highest values. Only EO treatment significantly reduced translucency.

Sterilization method influenced the mechanical and optical properties of 3D-printed surgical guides without compromising dimensional accuracy.

The findings provide evidence-based guidance for clinicians to select sterilization protocols that preserve the functionality of 3D-printed surgical guides and ensure precision in implant placement.