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

Abstract

Introduction and aims: 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. Methods: Twenty specimens were fabricated using a digital light processing printer and divided into 4 groups (n = 5): non-sterilized control, autoclaving (121 degrees C, 15 minutes), EO gas (55 degrees C, 60 minutes), and hydrogen peroxide gas plasma (<57 degrees 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&apos;s post hoc test. Results: All sterilized groups maintained internal fit deviations within clinically acceptable tolerance (+/- 120 mu m), 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. Conclusion: Sterilization method influenced the mechanical and optical properties of 3Dprinted surgical guides without compromising dimensional accuracy. (c) 2026 The Authors. Published by Elsevier Inc. on behalf of FDI World Dental Federation. (http://creativecommons.org/licenses/by-nc-nd/4.0/)