There are several reasons to use or not to use a membrane in this situation as I see it. The main reason to use a membrane , as we all know, is to preclude connective and epithelial tissues from invading the graft site and possibly limiting the GBR. So, if you use a block graft and need a complete fill of the spaces around the graft and use particulate materials whether autogenous or not, then I would use a membrane to enhance the result.

If on the other hand, you use a block graft that is complete for the area intended for placement of an implant, and otherwise there is ample bone available, then a membrane would not be necessary.

One must also think about possible exposure of a membrane. We always try and plan for sustained primary closure without exposure of the graft, but it can be worse if a membrane is in place, so I consider that as well.

In short, my choice of membrane use, or not, is related to soft tissue considerations regarding the goals and needs of the grafted area.

I look forward to others thoughts on this as well.

Yes absolutely use a membrane over your block grafts. Compartive studies published by Widmark (1997) and Antoun (2001) where they compared one site with membrane and one without found that resorption was least when a membrane was used. OssixPlus is my current membrane of choice.

Surgical prinicples of guided bone regeneration dictate the use of a membrane. A membrane is needed regardless of whether you are doing a particulate or block grafting.

This is a nice study to read:

Widmark G, Andersson B, Ivanoff CJ.
Mandibular bone graft in the anterior maxilla for single-tooth implants. Presentation of surgical method.
Int J Oral Maxillofac Surg. 1997 Apr;26(2):106-9.

Nine patients with 10 implants were included in the study. A bone graft from the symphyseal region of the mandible was used to augment the ridge 4 months before implant insertion. All implant sites showed a sufficient amount of bone at the time of implant insertion. One implant was not integrated at the time of abutment connection. Bone resorption after augmentation was assessed by measurements of the width of the alveolar ridge at four different levels. The measurements were performed before and after the bone-grafting procedure, at implant insertion and at abutment connection. The bone resorption in the buccal/palatal direction was 60% when measured from the time of bone grafting to abutment connection. The bone resorption was already obvious after 4 months (25%). The results indicate that the described bone grafting technique is applicable in patients with a narrow alveolar ridge, even though the resorption of the graft was extensive.

Loved this article. It answers all:

http://www.nxtbook.com/nxtbooks/specops/jiacd_201003/#/46

In the last six years and over 800 sucessful cases of defect repair (many extreme) I have not used a membrane or autogenous once.
The traditional membranes can impede the periosteal blood supply thus interfering with the bone regeneration. There are synthetic graft materials that are cell occlusive yet vascular porous and are stable as they set.
Technique sensative but we use them daily with over 99% success.
Just another way of doing things that is more sympathetic to the patient and no foreign material.
Have shown and spoken on these materials globally.
Peter

There is a a lot of newer evidence showing the benefits of membrane free grafting see ( podoropolus amd smeets for 2 papers.Materials include fortoss Vital or Genex ( US Orthopedic material) , Easygraft from Swtitzerland and Bond Bone from Israel ).
I will be speaking on their use again in Copenhagen next week but generally dentistry has many solutions to problems and we learn through experience.
Regards
Peter

All Beta TCP products some with CaSo4 and Easgraft with a poly lactide coating and is used with a medical biolinker. Genex is the FDA approved Orthopaedic equivalent of Vital.
Regards
Peter

This is my receipt for membranes;
For socket preservation (intact walls): Graft + Osteogenics txt-200 (Non resorbable d-Ptfe ideal for open healing)
For dehisense and fenestration around implants: Graft + Resorbable collagen membrane (Bio-gide or Mem-Lok)
Multiple extraction walls missing: Graft + more rigid and long lasting membrane (mem-Lok)
Really need to thicken hard tissue: Titanium reinforced non-resorbale membranes

I miss the Ossix membrane, I always used that for block grafts.