Guided bone regeneration with particulate vs. block xenogenic bone substitutes: a pilot cone beam computed tomographic investigation.

Aim To test whether an equine bone substitute block used for guided bone regeneration ( GBR) of peri-implant defects differs from bovine block or particulate bone substitutes regarding the hard and soft tissue contours of the augmented ridge. Material & Methods Two semi-saddle bone defects were prepared in each side of the mandible of eight dogs, and one titanium implant was inserted into every defect. The defects were randomly allocated to receive one of the following treatments: bone augmentation by GBR using (1) particulate deproteinized bovine bone mineral ( DBBM) + a collagen membrane ( CM), (2) block DBBM + CM, (3) equine bone substitute block + CM, and (4) empty controls. After 4 months, the jaws were scanned by means of cone beam computed tomography ( CBCT). CBCT analysis was performed in one central and two lateral (mesial and distal) regions of interest ( ROI) of each site evaluating the horizontal thickness of the augmented hard tissue ( HThard tisue) and the total thickness of hard and soft tissue ( HTtotal). The Wilcoxon-Pratt signed rank test was used for statistical analysis. Results In the majority of ROIs, equine and bovine blocks rendered significantly higher values in HThard tissue and HTtotal than controls ( P < 0.05). Generally, equine blocks reached the highest values in HThard tissue and HTtotal followed by DBBM blocks and particulate DBBM. The differences in HThard tissue and HTtotal between GBR groups were not statistically significant ( P > 0.05). In the central ROI, HThard tissue at the level of the implant shoulder measured 1.7 ± 1.4 mm for equine blocks, 1.7 ± 1.0 mm for DBBM blocks, 0.9 ± 1.2 mm for particulate DBBM, and 0 ± 0 mm for controls. The corresponding values in the lateral ROI reached 1.9 ± 1.1 mm for equine blocks, 1.2 ± 0.8 mm for DBBM blocks, 1.0 ± 0.9 mm for particulate DBBM, and 0 ± 0 mm for controls. Conclusions GBR with bone substitute blocks lead to higher ridge dimensions than empty controls. The equine block with CM rendered the most favorable outcomes in hard and soft tissue contours followed by DBBM block and DBBM granulate with CM. [ABSTRACT FROM AUTHOR]