Tenting screws at grafting site: advice?

3mm is good. Instead of screws you can use two layers of barrier membrane, that usually works well. Mattress sutures are indicated for this augmentation. The primary purpose of graft material is to maintain space for angiogenesis and osteogenesis. Collagen is probably just as good a barrier as any.

First off, predictable vertical gains through any mode is difficult. Everything you mentioned is a factor in your 3 mm of gain: --Should I have used mattress sutures? If the surgical site remained closed throughout healing, then the mattress would not have helped. The major benefit of any mattress suture is to take the load off the wound margin and place it across a larger segment of tissue. This will aid in achieving and maintaining tension free primary closure especially during the initial swelling phase. Secondly, certain mattress suture designs are useful for securing a membrane over a graft, minimizing and often eliminating the need for bone tacks and screws to stabilize the membrane. --Should I have used pericardium instead of plain old collagen? I don't think that would have made any significant difference. Based on my personal experience, despite manufacturer claims, collagen containing membranes experience significant resorption in approximately 4 months, with some lasting longer and others shorter depending on various factors. This is not enough time to allow for space maintenance where a compressive force is present. I have found that horizontal augmentations seem to be well vascularized at 4 months, but those grafts are protected by the palatal or lingual plates of bone. For vertical grafts, the fastest healing vertical gains I've seen are through block grafts, both autogenous and allogenic. In these grafts, it is my preference to place a collagen membrane over them and the surrounding particulate, with the intent of re-entering the site in 4 months for implant placement. For particulate only grafts, I will will use allogenic/autogenic particulate under a collagen membrane, but this must be mixed with PRF, either membranes or liquid. After 4 months. I am seeing vital bone, but vertical gains beyond 3-4 mm are not predictable unless the defect is surrounded by healthy and abundant bone on at least 2 sides. For larger gains, I will use a bovine xenograft/autograft combination, preferably with some form of PRF mixed in, but this must be covered with semi-rigid protection, my preference being titanium reinforced dense PTFE membrane. For larger areas, this titanium reinforced membrane will be supported by a tenting screw at least every 5 mm. The reason that PTFE is used is to ensure the particulate graft has enough time for angiogenesis to occur throughout the entire graft, recognizing that the outermost layers of the graft will not receive any meaningful nutrition or vascularization from periosteum, which will be occluded by the PTFE. The rigid support achieved through the use of tenting screws and titanium reinforcement is to ensure that the compressive forces of the mount, notably the patient's tongue, are not going to smush the graft during the vascularization process. --I have two-time grafted sites before but never at a tenting site. I don't mean to sound smart, but with this level of experience, you should be happy with a 3 mm gain. Many clinicians will never achieve even this amount of gain in a vertical dimension. --Should I just go ahead and use a titanium membrane? This depends on the patient's goals and expectations. Are short implants an option here? Is the soft tissue healthy and scar-free enough to endure another augmentation, knowing that you will have to significantly advance the buccal flap to achieve primary closure? Are you prepared to regain vestibular depth and also perform a large epithelialized free gingival graft to reestablish an adequate zone of keratinized mucosa? Hope this helps.

There is always shrinkage with any form of particulate graft, that's why we have to over-build in any procedure like this, so this result is one that should be expected. At the second stage exposure procedure, when you place healing caps, you can mobilize the labial flap again then provide more augmentation, with another membrane. This can provide a better, more complete result, one much closer to what you were trying to achieve in the first place. Try it!

All the above comments are nmade by people with vast experience, and the common denominator here is.....we can never be sure that things will turn out the way we intended them to......so when you consider what you started out with......4 mm of bone that the screw was placed into and an additional 3mm gain......tells me that oyu can place a six mm implant, and hopefully with a wide diameter.... so you have done your patient a service..... there is still the other possibility of harvesting bone from other areas, and screwing down a sizable piece of bone to the defect, and leaving enough holes in it to get revascularization...… may help as well.

How much bone did you expect? Bone grows at about 3mm/month so 3mm after 3 months is what you should have expected even in ideal conditions.

Regeneration of vertical is dependent on a couple of parameters. Most important is vascularity to the graft site. Was there a a prosthesis hindering blood supply ? Have you considered cortical bone dowels with perhaps a Flexo-Membrane or Flexo-Plate over the grafted site.

I think most of the comments made have merit. Onlay grafting for vertical height and width in the maxilla is challenging. With this case there is no mention of the patients age, any medical issues, opposing dentition and habits. Host response is variable and may be the main factor in the determination of the technique used as well as the materials chosen. One type and technique does not fit all cases. Also the site preparation was not discussed and in my mind is as critical as the space creation and closure. Tent screws are great but may be limiting in a flat one surface contact defect in the maxilla using allograft of small particle size and and rapid resorption and remodeling contributing to loss of planned bone volume. Using adjunctive materials such as PRP, PRF, BMP would be helpful with these allografts but incorporating a cortical component for graft stability and time for remodeling is a consideration. My preference for these type of defects is the use of autogenous cortical/ cancellous particulate or block grafts secured or with KLS Martin Tent Screws (I developed them about 8 years ago for them), with an overlying resorbable membrane of PRF with a double layered non tension closure. I might consider adding allograft as a graft expander if needed and I would choose a dense material ie. bovine bone for stability of the graft. I would look to initiate a significant site preparation with underling bleeding to vascularize the graft. These patients, with these flat anterior maxillas need to be compliant patients and I would not have them wear any prothesis that would put any pressure on the area for at least 4 to 6 weeks. After all is said and done, I would tell the patient that there may be a need for additional grafting at the time of implant placement and then hope for the best. Just my 2 cents.

I agree with Dr Teague and Joel: a reinforced dPTFE or TiMesh is ridged and often needed in moderate to larger defects. I would fixate a collagen membrane with Tacs, as movement of the membrane is an issue. Vertical mattress sutures are indicated in this GBR yet 3mm height gain is respectable, esp w the technique you used. The vascularity of the host site must be managed well, a well released flap for tension free closure and no pressure from the temporary. Cut off the buccal flange and rely on the palate and denture adhesive.

Thank you all for all your advice. I have grafted for 20 years and this case, I guess, was a little disappointing ( with ego and all) . if I read you all correctly, in theory, I can go back in and gain another couple mm ?