Alveolar ridge preservation with guided bone regeneration and a synthetic bone substitute or a bovine-derived xenograft: a randomized, controlled clinical trial

The aim of this randomized, controlled clinical trial was to compare the potential of a synthetic bone substitute or a bovine-derived xenograft combined with a collagen membrane to preserve the alveolar ridge dimensions following tooth extraction.Twenty-seven patients were randomized into two treatment groups following single tooth extraction in the incisor, canine and premolar area. In the test group, the alveolar socket was grafted with Straumann Bone Ceramic (SBC), while in the control group, Bio-Oss deproteinized bovine bone mineral (DBBM) was applied. In both groups, a collagen barrier was used to cover the grafting material. Complete soft tissue coverage of the barriers was not achieved. After 8 months, during re-entry procedures and before implant placement, the horizontal and vertical dimensions of the residual ridge were re-evaluated and trephine biopsies were performed for histological analysis in all patients.Twenty-six patients completed the study. The bucco-lingual dimension of the alveolar ridge decreased by 1.1+/-1 mm in the SBC group and by 2.1+/-1 in the DBBM group (P<0.05). Both materials preserved the mesio-distal bone height of the ridge. No differences in the width of buccal and palatal bone plate were observed between the two groups. The histological analysis showed new bone formation in the apical part of the biopsies, which, in some instances, was in direct contact with both SBC and DBBM particles. The coronal part of the biopsies was occupied by a dense fibrous connective tissue surrounding the SBC and DBBM particles.Both biomaterials partially preserved the width and the interproximal bone height of the alveolar ridge.