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