Freeze-dried aura mater for guided tissue regeneration in post-extraction dental implants: A clinical and histologic study
The purpose of this study was to evaluate freeze-dried aura mater membranes (FDDMA) used in conjunction with dental implants inserted into extraction sockets in order to increase bone regeneration. Researchers took 69 patients with a mean age of 44 years. They used 85 soft membranes to cover 85 implants. These membranes were cadaveric pure aura mater sterilized under X-rays. These membranes were used in conjunction with guided tissue regeneration around implants placed in extraction sockets. Ten percent of the patients had prosthetic abutments attached and restorations completed immediately. The rest had a healing period of three to six months prior to placement. The membranes were at least 2-3 mm over the margins of the defects. They were inserted over the implant and fixed in place with a cover screw. A reentry was done one to eight months after the surgery, and a biopsy of the membrane and the bone was taken. The results showed pert-implant tissues that were healthy with an average probing depth of 1.5 to 4 mm. Radiographs revealed no radiolucencies and bone closely apposed to the implant.
After six months, at reentry, the membrane was seen and could be detached from the underlying tissues in some of the cases. In a minority of the cases, the membrane was not seen. In 4% of the cases the membrane was exposed after about 20 days. This was treated with hydrogen peroxide and 0.12% chlorhexidine. This reepithelialized uneventfully. At three months the tissue under the membranes was similar to mature bone. In some cases this tissue could not be penetrated by the probe, although in some cases the probe could penetrate. Bone biopsy showed aspects of spongious lamellar bone without any signs of inflammation of resorptive activity. FDDMA is a very strong and resistant material. It elicits limited cellular inflammatory reaction. The disadvantages include the risk of disease transfer and the irregular degree of adsorption that seems to be linked to the presence of bacteria. [M.C.R.]
Fontana, E., P.Tristi, and A. Piatelli, J Periodont, 65:658, 1994