Introduction: Bacterial adhesion to biomaterials used in guided bone regeneration procedures represents a critical factor for the success of treatments in implantology. Microorganisms associated with persistent infections with Enterococcus faecalis have the ability to survive, form biofilms, and resist adverse conditions.

Objective: Evaluate which surface of the PTFE and Zirconia membranes (advanced ceramic membrane based on zirconium dioxide ZrO₂) has greater growth and bacterial contamination of the Enterococcus faecalis strain, in vitro study.

Materials and methods: The researchwas quantitative, observational, longitudinal, experimental, and in vitro, with PTFE and zirconia membranes inoculated with the bacteria under controlled conditions and evaluated at 2 and 7 days. Bacterial growth was identified using the imprint technique and with the count of CFU/ml, which were transformed to log10 for statistical analysis (non-parametric Mann-Whitney and Wilcoxon tests) with a 95% confidence level.

Results: The PTFE membranes exhibited greater bacterial growth compared to the zirconia membranes at both evaluated time points. Likewise, bacterial proliferation was evidenced during the incubation period, with a statistical variation having a p-value <0.05.