Assessment of Guided Bone Regeneration in Atrophic Anterior Maxilla

Assessment of Guided Bone Regeneration in Atrophic Anterior Maxilla using native Collagen vs Titanium Reinforced Polytetraflouroethelene Membranes using an organic bovine Bone mineral.Reconstructive surgery is necessary before implant placement to regenerate bone defects caused by atrophy, dental trauma, extractions or periodontal disease . Success rate of implants is related to the correct position and angulation of implants in residual crest, so that height and thickness of bone augmentation can allow predictable results ,With this in mind, it is important to establish sound clinical concepts with clearly defined parameters that lead to successful esthetics in the anterior maxilla, with long-term stability of the peri-implant tissues.

The most popular surgical procedures to obtain bone augmentation are: bone grafts, guided bone regeneration, maxillary sinus floor elevation, and bone osteogenesis distraction.

Guided bone regeneration (GBR) is a surgical technique that uses barrier membranes to promote osteoblast cells proliferation and exclude other cells such as epithelium and connective tissue cells. GBR is often combined with bone grafting procedures.

Bone grafts are integrated into native bone with three different processes: osteogenesis, osteoinduction and osteoconduction; Osteogenesis is the formation of new bone from osteocompetent cells and is the only process where the graft itself can induce Bone augmentation, Osteoinduction induces Bone Augmentation from the differentiation and stimulation of mesenchymal cells by the bone-inductive proteins, Osteoconduction is the formation of Bone Augmentation along a scaffold from osteocompetent cells of the recipient site .

There are 2 Types of membranes:

III. Non Resorbable membrane IV. Resorbable membrane

Non-resorbable membranes:

With the presentation of the first successful GBR procedures and the subsequent wide and successful application of ePTFE membranes, this material became a standard for bone regeneration. Expanded PTFE is characterized as a polymer with high stability in biological systems. It resists breakdown by host tissues and by microbes and does not elicit immunologic reactions. A frequent complication with membrane application in conjunction with implants is membrane exposure and infection Wound dehiscence and membrane exposure have been reported to impair the amount of bone regenerated in a number of experimental animal and clinical investigations

Bioresorbable membranes:

The requirement of second surgical procedure for the removal of Non Resorbable barrier membrane(NRBM) led to the introduction of bioresorbable barrier membranes (RBM). The advantages of RBM compared to NRBM were as follows:

1. Improved soft tissue healing,
2. Incorporation of the membranes by the host tissues (depending on material properties),
3. Quick resorption in case of exposure, eliminating bacterial contamination. Today, a lot of RBM are commercially available including collagen, freeze-dried fascia lata, freeze-dried dura mater allografts, polyglactin-acid, polylactic acid, polyglycolic acid, polyorthoester, polyurethane, polyhydroxybutyrate, etc.