Radiographic and histological evaluation of bone formation induced by rhBMP-2-incorporated biomimetic calcium phosphate material in clinical alveolar sockets preservation

PURPOSE: We assessed the efficiency of low-dose recombinant human bone morphogenetic protein-2 (rhBMP-2) incorporated biomimetic calcium phosphate on β-tricalcium phosphate (β-TCP) (rhBMP-2/BioCaP/β-TCP) on bone formation in a model of socket preservation using cone beam computed tomography (CBCT) scanning and histological examination. METHODS: Forty patients undergoing minimally invasive single-root tooth extraction for dental implantation were randomized to three groups according to the material used for socket preservation: filling with rhBMP-2/BioCaP/β-TCP, β-TCP, or natural healing (kept unfilled) (controls). The alveolar sockets (including the control group) were covered by two-layer collagen membranes and sutured. Two CBCT scans were taken, one immediately after socket preservation procedure (baseline) and another 6 weeks later. Gray values (GVs) obtained from CBCT were recorded. During insertion of the dental implant, biopsies were taken and analyzed histologically for new bone formation, residual material, and unmineralized bone tissue at the core of the biopsy. RESULTS: The mean (± standard deviation) changes of GVs of the CBCT scans at the central area of filled materials were as follows: 373.19 ± 157.16 in the rhBMP-2/BioCaP/β-TCP group, 112.26 ± 197.25 in the β-TCP group, and -257 ± 273.51 in the control group. The decrease of GVs in the rhBMP-2/BioCaP/β-TCP group as compared with the β-TCP group was statistically significant (P < 0.001). Differences in new bone formation (P = 0.006) were also found: 21,18% ± 7.62% in the rhBMP-2/BioCaP/β-TCP group, 13.44% ± 6.03% in the β-TCP group, and 9.49% ± 0.08% in controls. The residual material was10.04% ± 4.57% in the rhBMP-2/BioCaP/β-TCP group vs. 20.60% ± 9.54%) in the β-TCP group (P < 0.001). Differences in unmineralized bone tissue (P < 0.001) were also found (68.78% ± 7.67%, 65.96% ± 12.64%, and 90.38% ± 7.5% in the rhBMP-2/BioCaP/β-TC, β-TCP, and control groups, respectively). CONCLUSIONS: This study shows that rhBMP-2/BioCaP/β-TCP is a promising bone substitute with fast degradation and potent pro-osteogenic capacity that can be useful for socket preservation in implant dentistry. Trial registration: ChiCTR, ChiCTR2000035263. Registered 5 August 2020, https://www.chictr.org.cn/ChiCTR2000035263. GRAPHICAL ABSTRACT: [Image: see text]