Preclinical Comparison of Xenografts in Circumferential Defects Around Dental Implants

Objectives: The aim of this study was to evaluate and compare bone growth and implant integration of a simultaneous dental implant placement and bone augmentation procedure in a contained circumferential defect model with two commercially available bone substitutes in the mandible of minipigs.
Methods: Four circumferential defects were created in each mandible of 10 minipigs and Straumann Bone Level Tapered Roxolid^® implants with an SLActive^® surface were placed. The defects (2 mm around each implant) were augmented with either cerabone^® (test) or Bio-Oss^® (control) and covered with a collagen barrier membrane (Jason^®, botiss, Germany). Five animals were evaluated after 8 weeks, and five after 12 weeks of healing by means of histological and histomorphometric analysis (n=10).
Results: After 8 and 12 weeks, adequate newly formed bone was observed for all defect sites, with no significant differences between the groups. Residual graft material was comparable in both groups after 8 and 12 weeks, with no significant resorption in either group. The extent of implant integration, was also not significantly different between the groups. Slightly greater variability was observed regarding bone height within the cerabone^® group.
Conclusions: From the histologic and histomorphometric comparison of two similar natural bovine bone minerals, Bio-Oss^® and cerabone^®, in a well-defined contained circumferential defect in the mandible of minipigs it can be concluded that bone formation, tissue composition in the defect, implant integration in the augmented defect, and height of the bone crest of augmented bone in relation to the coronal aspect of the implant were all equivalent for both materials. The results suggested that cerabone^® can be used as a suitable bovine bone graft material, especially where extended volume stability and slow resorption of the graft material are required.