CytoFlex e-PTFE Membrane vs High-Density PTFE Membranes?

smooth_cytoflexA common question we get regarding the CytoFlex Tefguard Non-Resorbable ePTFE Membranes, is: what is the difference between the Cytoflex Tefguard Expanded PTFE membrane, or ePTFE, and other Non-Resorbable PTFE membranes High-Density PTFE, or dPTFE, membranes.

Before getting a brief discussion of this matter, we want to point out that there is already quite a bit written about various types of PTFE membranes, so we certainly don’t claim that the following answer is an exhaustive treatment of this topic. We urge readers to consult additional resources, a few of which are linked to below. In addition, feel free to add your comments below.

Porosity: The Primary Difference
With that being said, the key point to understand is that PTFE membranes can be divided into two general types, based on their unique structure: expanded-PTFE (e-PTFE) and high density-PTFE (d-PTFE). The CytoFlex membranes from Unicare Biomedical, are e-PTFE membranes, as opposed to other membranes, which are d-PTFE membranes.

The basic difference between e-PTFE membranes and d-PTFE membranes is in regards to their porosity, which is a function of their differing manufacturing processes. e-PTFE is stretched on a microscopic level, which creates numerous small pores on the membrane. In contrast, d-PTFE, is manufactured specifically to eliminate expansion, and greatly reduce these pores, resulting in a material with a submicron (0.2 μm) pore size. Because of this tiny pore size, bacterial infiltration into the site is eliminated with d-PTFE.

The e-PTFE membranes can be further divided into two categories, macro-ePTFE and micro-ePTFE depending upon the membrane’s construct. Macro-ePTFE refers to ePTFE membranes that exhibit macro pores, which allow cellular ingrowth across the membrane. The CytoFlex® Tefguard® membranes, from Unicare Biomedical, are micro e-PTFE membranes. The small and torturous pore paths of CytoFlex® Tefguard® micro-ePTFE membranes block cellular and bacteria penetration across the membrane, as opposed to macro e-PTFE membranes which require primary closure.

Similar Clinical Results, but Different Benefit Profiles
In terms of the clinical effectiveness of e-PTFE vs d-PTFE, it is worth noting that a recent study published in Clin Oral Implants Res. 2014, concluded that: “both d-PTFE and e-PTFE membranes showed identical clinical results in the treatment of vertical bone defects around implants, using the GBR technique.”

Despite the similar clinical results, clearly there are different “selling points” when it comes to e-PTFE vs d-PTFE. As it pertains to e-PTFE, the material with a longer history of use, the stretched nature of this membrane, and the larger pores, may improve nutrient permeation across the e-PTFE membrane, when compared to d-PTFE, and allow for healthy bone regeneration.

However, at the same time, the tiny pore material of d-PTFE has its own benefits. Specifically, d-PTFE completely blocks bacteria allowing it to better withstand exposure in the oral environment, and thus primary soft tissue closure is not required with d-PTFE membranes. Furthermore, due to its surface, attachment to tissues with d-PTFE is weak, and thus removal of the d-PTFE membranes is a bit easier when compared to e-PTFE membranes.

It is worth noting, though, that CytoFlex e-PTFE membranes, have been used successfully without primary closure, as is demonstrated in this clinical case. Furthermore, soft tissue in-growth is not significant enough with CytoFlex e-PTFE membranes, and so the material is easily retrieved. Interestingly, the greater soft tissue adhesion of e-PTFE can be considered beneficial, as it improves the seal around the membrane, providing a more secure and tight barrier over the site.

Additional Resources:
1. Current barrier membranes, Journal of Prosthodontic Research Volume 57, Issue 1, January 2013, Pages 3–14. Yunia Dwi Rakhmatia, DDS, Yasunori Ayukawa, DDS, PhD.
2. Expanded vs. dense polytetrafluoroethylene membranes in vertical ridge augmentation around dental implants, Clin Oral Implants Res. 2014 Jul;25(7):859-66. Ronda M1, Rebaudi A, Torelli L, Stacchi C.

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Other Related CytoFlex e-PTFE Membrane Questions

Cytoflex® Tef-Guard® membranes were designed to serve as a barrier to contain the bone graft material and prevent soft tissue and bacteria in-growth. At the discretion of the practitioners, the barriers have been used in primary coverage and non-primary coverage situation when soft tissue coverage is lacking. The membrane was designed to block off bacteria and thus exposure of the membrane does not result in infection and case failure.

In general within three to four weeks the membrane will need to be removed. This will allow enough time for the osseous tissue to begin forming and to be able to resist soft tissue from invading the graft site. However, at the discretion of the clinician, primary closure and longer healing times may be considered, if desirable.

Under primary coverage condition, Cytoflex® Tef-Guard® membrane may be easily removed by creating a small incision in its proximity. With forceps, firmly grasp a border of the material and remove it from the tissue. Local anesthesia is normally used for this procedure. In non-primary coverage situation, the membrane may be removed by grasping with forceps and removing it with a gentle tug. After membrane removal, re-epithelialization will occur within two to three weeks to complete the healing process. Final bone maturation will take place for six to twelve months from the time of implantation. This time frame should be considered in treatment planning cases involving heavy prosthetic loading of regenerated bone.

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