Bone regeneration using bilayer bone augmentation around dental implants: A preliminary study by micro-CT in dogs

The purpose of this preliminary study was to compare the effects of the bilayer bone augmentation technique (BBA) for the treatment of dehiscence-type defects around implants and evaluate the role as a membrane of the xenogenic bone positioned as the outer layer in the BBA technique using a micro-computed tomography (micro-CT). Four standardized dehiscence defects were prepared on each mandible bilaterally in 3 dogs and 1 implant was placed per defect, where each defect was treated with autograft (AB), xenograft (XB), BBA technique, or negative control without a membrane. Two months post-regenerative surgery, sectioned bone blocks were obtained. The image acquisitions were then scanned by micro-CT. Bone volume (BV), horizontal bone width (HBW) and vertical bone height (VBH) were measured through the analyses program. The BV were 11.08 mm3, 10.42 mm3, 8.1 mm3, and 7.01 mm3 in XB, BBA, control, and AB group in sequence of high value, respectively. HBW were 1.33 mm, 1.3 mm, 1.06 mm, and 1.03 mm in XB, BBA, AB, and control group, respectively. VBH were 4.88 mm, 4.85 mm, 4.74 mm, and 4.67 mm in XB, BBA, AB, and control group, respectively. However, there was no significant difference between the 4 groups. VBH tended to be higher in sequence of control, AB, BBA, and XB group (p for trend <0.05). The results showed the usefulness of the BBA technique involving mechanical support for prolonged space maintenance of xenogenic bone, for the treatment of dehiscence-type defects around implants. However, further studies with a larger sample size are required to confirm the results.