Bone Volume Dynamics and Implant Placement Torque in Horizontal Bone Defects Reconstructed with Autologous or Xenogeneic Block Bone: A Randomized, Controlled, Split-Mouth, Prospective Clinical Trial

The aim of this study was to evaluate volumetric stability of autologous and xenogeneic block grafts and primary stability of implants in maxillary grafted areas.Each patient received one autologous block and xenogeneic block, both covered with a membrane. Bone thickness measurements clinically and tomographically were made before, immediately, and 6 months postoperatively. After 6 months, identical implants were placed in each grafted area, and primary stability was measured.Eight patients with anterior horizontal bone defects were selected. Clinical outcomes at 6 months postgrafting in the autologous block revealed a mean thickness of 7.4 ± 1.6 mm, with an initial mean measurement of 3.4 ± 1.7 mm and 2.6% resorption, whereas the mean in the xenogeneic block was 8.9 ± 1.5 mm, 3.3 ± 1.6 mm, and 7.3%, respectively. Tomographic evaluation of the thickness at 6 months postgrafting in the autologous block was a mean 7.8 ± 1.8 mm, with an initial mean of 3.7 ± 1.6 mm and resorption of 0%, while the mean in the xenogeneic block was 9.3 ± 1.6 mm, 3.6 ± 1.4 mm, and 2.1%, respectively. No significant difference in bone thickness was observed immediately or 6 months after the procedure. The mean implant placement torque was 32 ± 22 Ncm in the autologous block and 18 ± 9 Ncm in the xenogeneic block (P = .004).Xenogeneic block was shown to be a suitable alternative to reconstruct horizontal defects in the alveolar ridge that had undergone extensive resorption, though lower insertion torques were obtained during implant placement.