Volume 8 • 2021 • Issue 1

Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Patient A: Typical Regeneration This is a typical patient for GBR ( Fig. 1 ). The patient had a long-standing bridge (15–20 years) in the lower left quadrant, which has failed. The teeth have been removed and bone dehiscence is evident on both abutment teeth. The site is currently not suitable for an implant placement without significant bone grafting at the same time. In this case, I would build a bony ridge first, wait 6 to 7 months for healing and then proceed to implant placement. •  Step 1: Cortical perforation ( Fig. 2 ) Cortical perforations provide a source of marrow rich in undifferentiated mesenchymal cells that will differentiate into cells that will eventually form bone. Some studies argue that the bone decortication step is not necessary. However, I believe doing so would not confer any harm. •  Step 2: Bone material harvest ( Fig. 3 ) I then take bone material. In this case, I am using allograft — human bone from another donor — mixed with shavings of cortical autogenous bone harvested from the same site of the patient. It is preferable to overbuild to anticipate shrinkage. The scaffold from the allograft bone and the live cells from the autogenous bone provide osteoinductivity, osteoconductivity and osteogenic capability. These properties are crucial for successful regenerative outcomes. •  Step 3: Barrier membrane placement ( Fig. 4 ) The site is covered with a barrier membrane to exclude epithelial cells from contacting the regenerating bone. Most common membranes are made of collagen. In this case, a porcine peritoneal collagen membrane was used. 2 •  Step 4: Tension free primary closure ( Fig. 5 ) Closure creates a stable regenerative space that is protected from any interference from the outside. This environment allows for optimal healing and regeneration of bone. •  Step 5: Re-entry ( Fig. 6 ) Best bone regenerative outcomes generally happen after 6 to 9 months. For Patient A, we are about seven months in. Re-entry reveals a nice, regenerated ridge that looks like real bone. Bleeding bone also shows that it is a vital vascularized tissue. •  Step 6: Implant placement ( Fig. 7 ) According to the prosthetic prescription, the implants can now be placed in the regenerated ridge. In this case, I placed three implants which will eventually support a screw-retained bridge restoration. S upporting Y our P ractice 34 | 2021 | Issue 1