In Vitro Microbial Adhesion on the Surfaces of Various Polytetrafluoroethylene Membranes Used in Guided Bone Regeneration

Abstract

Aim: The aim of this study was to evaluate the adhesion of oral microorganisms on the surfaces of polytetrafluoroethylene (PTFE) membranes used in guided bone regeneration (GBR) procedures. Materials and Methods: In this study, three oral microorganisms (Streptococcus mutans, Porphyromonas gingivalis, and Candida albicans) were used, and six PTFE membranes were characterized by their surface roughness, contact angle (CA), and surface free energy (SFE). Microbial hydrophobicity was investigated, and adhesion was examined via DNA extraction and quantitative real-time PCR. Results: Significant differences were noted amongst the membranes with respect to SFE, CA, and roughness (p < 0.001). S. mutans was the most hydrophobic microorganism, followed by C. albicans and P. gingivalis. SEM analyses confirmed that the microorganisms adhered to all membranes, with Surgitime being the membrane that attracted the highest number of S. mutans (p < 0.001) and P. gingivalis (p < 0.001). By contrast, OsseoGuard-TXT was one of the membranes that attracted the lowest number (p < 0.001) of all three tested species. Conclusions: The results showed that microbial adhesion to PTFE membranes was affected by the membrane surface roughness and SFE, as well as the characteristics of the microorganisms. The most hydrophilic bacteria adhered the least to all the tested membranes, whereas membranes with a low surface roughness and high SFE attracted the lowest number of all the tested microbes. These results may guide the selection of an appropriate GBR membrane.

Keywords: C. albicans; P. gingivalis; PTFE; S. mutans; bone regeneration (guided)/GBR; membranes; microbial attachment; surface free energy.

Figure 1

A comparison of roughness and contact angles of the PTFE membranes examined. CA: contact angle; DII: diiodomethane; *: p < 0.05; and ***: p < 0.001.

Figure 2

The number of microorganisms adhering to the membranes (mean ± SD) and Gibbs free energy change calculations [$\mathrm{\Delta }{G}_{adh}^{d-p}$, mJ/m²], with values indicated in red. Membranes are listed according to decreasing numbers of the adhered microorganisms. Significant differences: * = p < 0.05; ** = p < 0.01; *** = p < 0.001; and ‡ = p < 0.001 compared to all other membranes; † = p < 0.001 between all other membranes (exception: the comparison between Cytoplast^TM TXT-200 and Surgitime for C. albicans).

Figure 3

Representative SEM images of microbial adhesion to the various membranes. Bar = 1 µm and magnification = 10,000×. Images for C. albicans were reproduced from Asfour et al. (2024) [10] under the open access Creative Commons CC BY 4.0 license.

Figure 4

Correlations between the extent of microbial adhesion, membrane surface roughness (a–c), and total surface energy (d–f) for the microorganisms examined.