Evaluation of a Double Layer Technique to Enhance Bone Formation in Atrophic Alveolar Ridge: Histologic Results of a Pilot Study.

The atrophic alveolar ridge has been a challenge in implant dentistry; various techniques using the principle of guided bone regeneration (GBR) have been applied in the past 2 decades.The aim of this study was to introduce and evaluate-clinically, histologically, and radiographically-a novel technique of regenerating a new bone in the atrophic alveolar ridge, which is based on the GBR principles, the double layer technique (DLT). Six patients with partially edentulous jaws with a residual bone width less than or equal to 4 mm in the maxilla were subjected to GBR. The sites were grafted using a DLT. At first, sites were grafted with allogenic bone and then a second layer of deproteinized bovine bone was placed. Next, grafted sites were covered with a resorbable membrane tucked with 2 titanium pins. Cone-beam computed tomography scans were obtained before and 5 months after DLT. In the latter case and during implant site preparation, trephine biopsies were obtained and processed for histologic and histomorphometric evaluation. In all cases, implants were successfully installed and primary stability was established. Implant diameter ranged from 3.8 to 4.1 mm. In all cases, radiographic findings showed increased alveolar ridge width before and after surgery. The new tissues consisted mostly of a variable amount of new trabecular bone, some loose connective tissue, blood vessels, and occasional inflammatory cells. All 15 implants placed had 100% survival rate after a 5-year follow-up. On the basis of these preliminary results, it seems that the double layer GBR technique may achieve satisfactory results from a clinical, radiographic, and histologic perspective favoring placement of dental implants in the atrophic maxillary alveolar ridge.