Bio-Oss® is a bovine-derived bone substitute frequently used in jawbone augmentation. Postoperative infections of bone grafts pose clinical challenges and may compromise graft survival. This study examines the impact of cold atmospheric plasma (CAP) treatment on Enterococcus faecalis-contaminated Bio-Oss® and evaluates possible changes in surface chemistry relevant to graft performance.

Bio-Oss® spongiosa blocks were sectioned, sterilized, and contaminated with E. faecalis for five days. Specimens were divided into four groups: untreated control and 5-, 10-, and 15-minute CAP treatments using the KinPen Med device (Neoplas Med, Germany), operated with high-purity argon gas (5 L/min) at 5 W output, with a nozzle-to-surface distance of approximately 10 mm. Bacterial load was quantified by colony-forming units (CFU), and surface characteristics were evaluated using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS).

CFU analysis showed no statistically significant difference between the control and CAP-treated groups (one-way ANOVA, p = 0.79). SEM images confirmed the presence of bacteria on all specimens, regardless of treatment duration. XPS revealed reduced carboxyl group content and increased oxygen levels on CAP-treated samples (15 min) compared to untreated Bio-Oss®. The findings indicate that CAP altered the surface chemistry of the material but did not effectively reduce bacterial contamination under the tested parameters.

CAP treatment did not result in a significant bacterial reduction on E. faecalis-infected Bio-Oss®. The limited effectiveness may be related to the porous architecture of the material and plasma quenching in the liquid phase. However, observed surface modifications could influence wettability and cell interactions. These findings are restricted to the ex vivo model used, and further research with positive disinfection controls, mixed bacterial biofilms, and optimized plasma parameters is required before clinical application.