Efeitos dos métodos de desinfecção e esterilização em guias de corte impressos em resina 3d para ressecções maxilofaciais: estudo biomecânico e microbiológico in vitro

Abstract

Objectives: This in vitro study evaluated the effect of the disinfection and sterilization methods on the microbiological efficacy, mechanical properties, and dimensional stability of 3D-printed surgical guides used in maxillofacial resections. Methods: Specimens were 3D-printed using an autoclavable resin (priZma 3D Bio Guide) and divided into four experimental groups: disinfection method: CHL, immersion in 0.12% chlorhexidine digluconate for 24 h; sterilization methods: STE, steam autoclave at 134 °C/5 min; HP, hydrogen peroxide plasma; CON, untreated control group. The microbiological growth using identification by MALDI-TOF-MS, flexural strength and elastic modulus by using three-point bending test, and dimensional stability by using digital photogrammetry with ImageJ® analysis were performed. Results: All experimental methods achieved total elimination of microorganisms (100%), differing significantly from the control group (75%). STE caused the most significant mechanical and dimensional changes on the 3D-printed resin, decreasing the flexural strength and increasing the elastic modulus. The use of CHL and HP preserved the dimensional stability, with CHL exhibiting the best dimensional stability in Δy and Δz (p<0.001). Macroscopic structural defects were observed when STE was used. Conclusion: Although all methods were microbiologically effective, autoclaving at 134 °C compromised the mechanical properties, dimensional stability, and caused structural defects in the 3D-printed resin. Hydrogen peroxide plasma sterilization provided the best balance between microbiological efficacy and preservation of the material's physical, dimensional, and fit characteristics, making it the most suitable method for heat-sensitive 3D-printed surgical guides.