Vertical bone augmentation with simultaneous implantation using deproteinized bovine bone block functionalized with a slow delivery of BMP‐2

Abstract

Objective We hypothesized that a biomimetic calcium phosphate (CaP) coating which incorporates morphogenetic protein 2 (BMP‐2) on the deproteinized bovine bone (DBB) blocks could be used to enhance the vertical alveolar ridge augmentation for the one‐stage onlay surgery with simultaneous implants insertion. We aimed to test this hypothesis in vivo. Material and methods Beagles dogs were used for the study (n = 6 specimens per group). One month after building the edentulous animal model, 4 mm vertical alveolar bone loss were surgically created and four groups of blocks (W × L × H: 7 mm × 10 mm × 4 mm) were randomly fixed onto the reduced alveolar ridge by implants: (a) DBB blocks alone (negative control group); (b) DBB blocks with superficial adsorption of 50 μg BMP‐2 (ad.BMP‐2 group); (c) DBB blocks coated by biomimetic CaP coating which incorporates 50 μg BMP‐2 (inc.BMP‐2 group); and (d) autologous bone blocks (positive control group). After 3 months of healing, samples were harvested for micro‐CT and histomorphometric analyses. Results In histomorphometry, the inc.BMP‐2 group showed a significantly thicker (coronal‐apically) and wider (buccal‐lingually) augmented bone area, better bone‐to‐implant contact than the negative control group. In both the micro‐CT and histomorphometry, the inc.BMP‐2 group showed more mineralized tissue than the negative control group and the inc.BMP‐2 group also showed significantly more newly formed bone and residual grafts than the negative control group in the upper half of the blocks. In micro‐CT, the inc.BMP‐2 group showed significantly more bone‐to‐graft contact percentage than the ad.BMP‐2 group. In both micro‐CT and histomorphometry, the inc.BMP‐2 group showed significantly more percentage of mineralized tissue than the ad.BMP‐2 group. No significant differences were found between the inc.BMP‐2 group and the positive control group either in micro‐CT or in histomorphometry. Conclusions The DBB blocks with coating‐delivered BMP‐2 significantly enhanced the efficacy of vertical alveolar bone augmentation, compared with the unloaded blocks and blocks with adsorbed BMP‐2, in the one‐stage onlay surgery with simultaneous implant insertion.

Biomimetic Calcium Phosphate Coating as a Drug Delivery Vehicle for Bone Tissue Engineering: A Mini-Review

“…The highest osteoinductive efficacy was obtained when BMP-2 was incorporated in the coatings [53]. Moreover, the bone argumentation via incorporated BMP-2 was also observed in the mandibular defect of Beagle dogs [45]. DBB blocks were implanted in the mandibular bone defect area and Ti implants were inserted into DBB blocks at the same time.…”

“…In a surface-adsorbed mode, the target molecules, such as BMP-2, are held at the surface of the underlying substrates loosely via an electrostatic interaction [19]. Therefore, the molecules are released rapidly within a biological milieu and diffuse rapidly away from the implantation site, unable to induce an uninterrupted osteogenic stimulus-response [24,45]. In contrast, the target molecules are tightly held by a strong covalent bond in the biomimetic-coating-incorporated mode [41].…”

“…DBB blocks were implanted in the mandibular bone defect area and Ti implants were inserted into DBB blocks at the same time. According to their results, the osseointegration between DBB blocks and Ti implants and the healing between DBB blocks and defected alveolar bone are both enhanced when BMP-2 is incorporated in the BioCaP coating instead of superficially adsorbed [45]. Apart from the abovementioned administration in dental implantology, BMP-2-incorporated BioCaP grafts have shown a higher osteogenic ability in the alveolar defect site during orthodontic treatment [64].…”

The Influence of Hyaluronic Acid Biofunctionalization of a Bovine Bone Substitute on Osteoblast Activity In Vitro

“…Recent studies analyzed combinations of BSMs with growth factors (e.g., BMP-2, VEGF) and PRF (platelet-rich fibrin). The findings of these studies illustrated that such biofunctionalized BSMs have the potency to accelerate and increase bone formation and vascularization as characteristic hallmarks of fast and sufficient bone regeneration [28][29][30][31][32][33]. As BSM modification with growth factors is technically challenging and restricted by legal requirements in most countries, further substances might be of interest for BSM biofunctionalization.…”

Animal models of vertical bone augmentation (Review)

“…Vertical alveolar bone defects may be designed according to different sizes of bone grafting materials or vertical bone augmentation techniques. Teng et al (66) extracted bilateral dog mandibular premolars; loss of the vertical alveolar bone was observed after 1 month of healing. In another study, Khojasteh et al (79) extracted the bilateral first and second mandibular premolar teeth bilaterally in dogs; after 4 weeks of soft tissue healing, critical size defects were evident.…”