Leaving the membrane exposed: when is this possible?

Cytoplast teflon membranes are left exposed, and Bioxclude (chorion) can be exposed and bio collagen technique with Bioguide can be exposed. The other membranes will break down sooner. Those are the ones I'm familiar with. The bone needs to be covered for best result an extraction site has a clot which can heal secondariy. Hope this helps.

A-PRF membranes can be left exposed. See site below. http://www.a-prf.com/en/

Teflon membranes are tougher to resorb and can occasionally be left exposed. Most collagen membranes resorb in about 4-6 weeks, some longer than others. When placing a resorbably collagen membrane to help hold the graft in place, it is inevitable in some cases, e.g. extraction sockets of large molars that some membrane will stay exposed, as primary closure is not possible. If they are sutured correctly and the graft particles are infused with good fresh blood, things should work out fine. Exception being heavy smokers. Anyways, these days, I avoid placing membranes where I have good full thickness flap over graft site. I find I have better results. Blood supply from the periosteum sometimes is restricted with a membrane, however well placed. In general, if the grafted particles receive good blood supply, and stay immobile during the healing phase, things will go well. Good Luck!

Cliff as always you are wise beyond your years I forgot about my PRGF membranes, since I don't trust my patients I usually will close primarily if I am not concerned about the vestibule. I have gotten some very nice preliminary results with the chorionic membranes also and am excited about using more of them!