Histomorphometric and 3D Cone-Beam Computerized Tomographic Evaluation of Socket Preservation in Molar Extraction Sites Using Human Particulate Mineralized Cancellous Allograft Bone With a Porcine Collagen Xenograft Barrier: A Case Series

The purpose of this study was to evaluate the results of socket preservation after extraction using human particulate mineralized cancellous allograft bone (MCAB) and type I porcine collagen membranes (PCM) as a guided bone regeneration barrier. Fourteen patients, 12 women and 2 men, were selected who had a diagnosis of one or more unsalvageable teeth with a treatment plan to replace them with implant-supported single crown restorations. Extractions were preformed atraumatically by sectioning teeth for removal to avoid damaging the socket walls and by immediately placing MCAB graft to fill the sockets. The sockets were occluded with a new PCM. The membranes were cut to overlap the facial and lingual (or palatal) socket rim by at least 5 mm (or more if necessary) to cover bony wall fenestration or dehiscence defects. Implants were then placed 16 weeks after the extractions and augmentation. The results were evaluated clinically, histomorphometrically, and with cone-beam computerized tomographic scanning. The formation of new bone in the treated sites averaged 11.2%, with a range of 1.8% to 43%, in bone biopsies trephined from the center of the grafted socket sites. Density, calculated with proprietary software and measured in Hounsfield units (HUs), was 543 HU with a range of 420 to 822 HU. The resulting new bone regeneration varied widely, but the barrier membranes showed potential for promoting significant bone regeneration. A larger sample of treated cases is needed. Wall defects did not appear to influence the histologic results, but the number of sites was too small to determine their significance.