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 ß-tricalcium phosphate (ß-TCP) (rhBMP-2/BioCaP/ß-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/ß-TCP, ß-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/ß-TCP group, 112.26 ± 197.25 in the ß-TCP group, and -257 ± 273.51 in the control group. The decrease of GVs in the rhBMP-2/BioCaP/ß-TCP group as compared with the ß-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/ß-TCP group, 13.44% ± 6.03% in the ß-TCP group, and 9.49% ± 0.08% in controls. The residual material was10.04% ± 4.57% in the rhBMP-2/BioCaP/ß-TCP group vs. 20.60% ± 9.54%) in the ß-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/ß-TC, ß-TCP, and control groups, respectively). CONCLUSIONS: This study shows that rhBMP-2/BioCaP/ß-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 .

Paradox: Curcumin, a Natural Antioxidant, Suppresses Osteosarcoma Cells via Excessive Reactive Oxygen Species.

Osteosarcoma (OS) is an aggressive tumor with a rare incidence. Extended surgical resections are the prevalent treatment for OS, which may cause critical-size bone defects. These bone defects lead to dysfunction, weakening the post-surgical quality of patients' life. Hence, an ideal therapeutic agent for OS should simultaneously possess anti-cancer and bone repair capacities. Curcumin (CUR) has been reported in OS therapy and bone regeneration. However, it is not clear how CUR suppresses OS development. Conventionally, CUR is considered a natural antioxidant in line with its capacity to promote the nuclear translocation of a nuclear transcription factor, nuclear factor erythroid 2 (NRF2). After nuclear translocation, NRF2 can activate the transcription of some antioxidases, thereby circumventing excess reactive oxygen species (ROS) that are deleterious to cells. Intriguingly, this research demonstrated that, in vitro, 10 and 20 µM CUR increased the intracellular ROS in MG-63 cells, damaged cells' DNA, and finally caused apoptosis of MG-63 cells, although increased NRF2 protein level and the expression of NRF2-regulated antioxidase genes were identified in those two groups.

Calcium Phosphate Ceramics and Synergistic Bioactive Agents for Osteogenesis in Implant Dentistry.

Implant-supported dental prosthetics are widely used in dental practice. Sufficient peri-implant bone tissue is a crucial prerequisite for the long-term success of this treatment, as insufficient peri-implant bone volume hampers dental implant installation and negatively influences dental implant stability. However, due to tooth extraction, bone metabolism diseases, and trauma, bone defects in the jaw are common in patients, particularly in the elderly and those suffering from underlying conditions. If this is the case, the alveolar ridge has to be augmented for reliable implant placement. Various biomaterials, growth factors (GFs) or GF-based products, and trace elements have been tested and used for alveolar ridge augmentation. Among those biomaterials, calcium phosphates (CaPs) are the most popular due to their promising biocompatibility, great osteoconductivity, and distinguishing osteogenesis. Combining CaPs with GFs or trace elements can further favor bone defect repair. This review mainly focuses on applying artificial CaP biomaterials and their combination with bioactive agents to repair bone defects in implant dentistry.

Virtual pterygoid implant planning in maxillary atrophic patients: prosthetic-driven planning and evaluation.

PURPOSE: The study aims to use cone beam computed tomography (CBCT) to (1) define the virtual valid length of pterygoid implants in maxillary atrophic patients from the prosthetic prioritized driven position and (2) measure the implant length engaged in the pterygoid process according to the HU difference of the pterygoid maxillary junction. MATERIALS AND METHODS: Virtual pterygoid implants were planned with CBCT of maxillary atrophic patients in the software. The entry and angulation of the implant were planned according to the prosthetic prioritized driven position in the 3D reconstruction image. The planned implant length and the valid length defined as the implant between the pterygoid maxillary junction and pterygoid fossa were recorded. The relationship between the implant and sinus cavity was also evaluated. RESULTS: A total of 120 CBCT samples were enrolled and virtually planned. The mean age of the patients was 56.2 ± 13.2 years. One hundred and sixteen samples could successfully place virtual implants according to the criterion. The mean implant length and mean implant length beyond the pterygoid maxillary junction were 16.3 ± 4.2 mm (range, 11.5-18 mm) and 7.1 ± 3.3 mm (range, 1.5-11.4 mm), respectively. Ninety percent of virtually planned implants had a close relationship with the sinus cavity, and implants exhibited longer lengths when they had no relation with the sinus. CONCLUSION: From a prosthetic prioritized driven position with fixed entry and angulation, pterygoid implants achieve adequate bone anchorage length beyond the pterygoid maxillary junction. Due to the individual anatomy and the volume of the maxillary sinus, the implants presented a different positional relationship with the maxillary sinus.

Biomimetic calcium phosphate coating on medical grade stainless steel improves surface properties and serves as a drug carrier for orthodontic applications.

OBJECTIVE: Recently, stainless steel (SSL) miniscrew implants have been used in orthodontic clinics as temporary anchorage devices. Although they have excellent physical properties, their biocompatibility is relatively poor. Previously, our group developed a two-phase biomimetic calcium phosphate (BioCaP) coating that can significantly improve the biocompatibility of medical devices. This study aimed to improve the biocompatibility of SSL by coating SSL surface with the BioCaP coating. METHODS: Titanium (Ti) discs and SSL discs (diameter: 5 mm, thickness: 1 mm) were used in this study. To form an amorphous layer, the Ti discs were immersed in a biomimetic modified Tyrode solution (BMT) for 24 h. The SSL discs were immersed in the same solution for 0 h, 12 h, 24 h, 36 h and 48 h. To form a crystalline layer, the discs were then immersed in a supersaturated calcium phosphate solution (CPS) for 48 h. The surface properties of the BioCaP coatings were analysed. In addition, bovine serum albumin (BSA) was incorporated into the crystalline layer during biomimetic mineralisation as a model protein. RESULTS: The morphology, chemical composition and drug loading capacity of the BioCaP coating on smooth SSL were confirmed. This coating improved roughness and wettability of SSL surface. In vitro, with the extension of BMT coating period, the cell seeding efficiency, cell spreading area and cell proliferation on the BioCaP coating were increased. SIGNIFICANCE: These in vitro results show that the BioCaP coating can improve surface properties of smooth medical grade SSL and serve as a carrier system for bioactive agents.

Icariin Has a Synergistic Effect on the Osteoinductivity of Bone Morphogenetic Protein 2 at Ectopic Sites.

OBJECTIVE: Establishing biocompatible, biodegradable, osteoconductive, and osteoinductive bone materials remains a challenging subject in the research of bone healing and bone regeneration. Previously, we demonstrated the osteogenic and osteoconductive effects of biomimetic calcium phosphate (BioCaP) incorporating with Icariin and/or bone morphogenetic protein 2 (BMP-2) at orthotopic sites. METHODS: By implanting the BioCaP granules incorporated Icariin and/or BMP-2 into the dorsal subcutaneous pockets of adult male Sprague-Dawley (S-D) rats (6-7 weeks old), we investigated the osteoinductive efficacy of the samples. Micro-computed tomography(micro-CT) observations and histological slices were used to verify the osteoinduction of this system on the 2nd and 5th week. Statistical significances was evaluated using Turkey's post hoc test of one-way analysis of variance. RESULTS: The osteoinduction of the BioCaP incorporated with BMP-2 or both agents was confirmed as expected. BioCaP with Icariin alone could not generate bone formation at an ectopic sites. Nevertheless, co-administration of Icariin increased bone mineral density (BMD; p < 0.01) (628mg HA/cm3 vs 570mg HA/cm3 ) and completely changed the distribution of newly formed bone when compared with the granules with BMP-2 alone, even though there was no significant difference in the volume of newly formed bone. In contrast, the BioCaP with both agents (37.86%) had significantly fewer remaining materials than the other groups by the end of the fifth week (53.22%, 53.62% and 48.22%) (p < 0.01). CONCLUSION: The co-administration of Icariin and BMP-2 increased BMD changed the distribution of newly formed bone, and reduced the amount of remaining materials. Therefore, Icariin can stimulate BMP-2 when incorporated into BioCaP granules at ectopic sites, which makes it useful for bone tissue engineering.

Gaining Soft Tissue with a Hydrogel Soft Tissue Expander: A Case Report.

In this case report, we describe the treatment of a patient referred to our clinic with a hopeless tooth 21 with an attached pontic. The aim of this case report was to, first, describe the advantages and disadvantages of gaining soft tissue with a self-inflating soft tissue expander before performing a bone augmentation procedure in implant dentistry in the esthetic zone. Second, we describe how an amalgam tattoo, caused by a previously performed apicoectomy that made the extension of the raised flap to cover the augmented site esthetically undesirable, was removed. Two silicone enveloped Osmed hydrogel self-inflating soft tissue expanders were placed submucosally on the right- and left-hand side of the amalgam tattoo. One of these two perforated the overlaying mucosa after 24 days. Both tissue expanders were removed, the amalgam tattoo was excided, the site augmented, and an implant with a crown and a pontic was placed.

Bone morphogenetic protein-2 incorporated calcium phosphate graft promotes peri-implant bone defect healing in dogs: A pilot study.

OBJECTIVES: The evaluation of three different drug delivery modes of bone morphogenetic protein-2 (BMP-2) in healing peri-implant bone defects in beagle dogs. BMP-2 was incorporated in or onto calcium phosphate (CaP) granules in various ways: (i) directly on the outer layer of granules CaP: as an adsorbed depot; (ii) during the entire precipitation process of CaP: an internally incorporated depot; or (iii) during the biomimetic coating precipitation of BMP-2 on the surface of CaP granules: as a coating incorporated depot. MATERIAL AND METHODS: After extraction of the lower molars and wound healing in 6 male beagle dogs, 36 implants were placed (n = 6 animal per group). Peri-implant bone defects were induced. The following treatment groups were evaluated: no treatment; air abrasive surface cleaning (SC) using hydroxyapatite; SC and the subsequent filling of the defect with CaP without BMP-2; SC plus the subsequent filling of the defect with CaP adsorbed BMP-2; SC plus the subsequent filling of the defect with CaP internally incorporated BMP-2; SC plus the subsequent filling of the defect with CaP coating incorporated BMP-2. Histological and histomorphometric analyses were carried out to quantify and compare the changes in bone tissue surrounding the treated implants. RESULTS: In Group 1 with no treatment, four implants were lost. Group 5 with the SC and the subsequent filling of the defect with internally incorporated BMP-2 biomimetically prepared CaP (BioCaP), whereby the BMP-2 is incorporated in the entire volume of all BioCaP particles, showed overall the best results to regenerate bone around the implants. CONCLUSION: This study concluded that the group treated with SC plus the subsequent filling of the defect with CaP BMP-2 internally incorporated BMP-2, whereby BMP-2 has been incorporated in the entire volume of all CaP particles, showed overall the best results when aiming to regenerate bone around the implants.

Crystalline Biomimetic Calcium Phosphate Coating on Mini-Pin Implants to Accelerate Osseointegration and Extend Drug Release Duration for an Orthodontic Application.

Miniscrew implants (MSIs) have been widely used as temporary anchorage devices in orthodontic clinics. However, one of their major limitations is the relatively high failure rate. We hypothesize that a biomimetic calcium phosphate (BioCaP) coating layer on mini-pin implants might be able to accelerate the osseointegration, and can be a carrier for biological agents. A novel mini-pin implant to mimic the MSIs was used. BioCaP (amorphous or crystalline) coatings with or without the presence of bovine serum albumin (BSA) were applied on such implants and inserted in the metaphyseal tibia in rats. The percentage of bone to implant contact (BIC) in histomorphometric analysis was used to evaluate the osteoconductivity of such implants from six different groups (n=6 rats per group): (1) no coating no BSA group, (2) no coating BSA adsorption group, (3) amorphous BioCaP coating group, (4) amorphous BioCaP coating-incorporated BSA group, (5) crystalline BioCaP coating group, and (6) crystalline BioCaP coating-incorporated BSA group. Samples were retrieved 3 days, 1 week, 2 weeks, and 4 weeks post-surgery. The results showed that the crystalline BioCaP coating served as a drug carrier with a sustained release profile. Furthermore, the significant increase in BIC occurred at week 1 in the crystalline coating group, but at week 2 or week 4 in other groups. These findings indicate that the crystalline BioCaP coating can be a promising surface modification to facilitate early osseointegration and increase the success rate of miniscrew implants in orthodontic clinics.

Plaque removal efficacy of a compacted dual-head power toothbrush: A split-mouth randomized clinical trial.

PURPOSE: To evaluate the plaque removal efficacy of a compacted dual-head power toothbrush (DH) in comparison with a single-head power toothbrush (SH). METHODS: 24 healthy university students were included in this split-mouth and single-center clinical trial. The DH and SH were randomly assigned to brush the left/right half mouth in the first visit. Testing time points were 30 and 60 seconds. Additionally, 15 and 45 seconds were set for the DH period. The overall, buccal, lingual, gingival marginal, and proximal plaque scores at different time points were recorded and determined by Rustogi Modification of the Navy Plaque Index. To avoid the influence of the right handedness, subjects were brushed in the second visit after 4 weeks, and the SH and the DH were assigned to the right/left half mouth in an opposite period to that of the first visit. RESULTS: 21 participants completed this study. Overall plaque score reductions of the SH and DH were 29% and 59% (P< 0.05) at 30 seconds, and the reductions were 47% and 77% respectively (P< 0.05) at 60 seconds. Using the DH for 45 seconds reduced significantly more overall, buccal, lingual, and gingival marginal plaque than that of using SH for 60 seconds (P< 0.05). The SH reduced plaque scores significantly less in the right and lower dentitions than left and upper dentitions respectively, while DH reduced comparable plaque scores between these dentitions. The DH is more effective in removing overall, buccal, lingual, gingival marginal, and proximal plaque in healthy university students than the SH, meanwhile DH showed comparable overall plaque reduction rates between different regions of the dentitions. CLINICAL SIGNIFICANCE: This compact dual-head power toothbrush provides a new option to carry out daily plaque control effectively.

Influence of radiotherapy on dental implants placed in individuals before diagnosed with head and neck cancer: focus on implant-bed-specific radiation dosage.

OBJECTIVES: The influence of radiotherapy on implants placed before diagnosed as head and neck cancer (HNC) is a potentially informative but poorly explored topic. The aims of this study were to investigate the influence of implant-bed-specific radiation dose on dental implants and to evaluate the impact of these implants on radiation dosimetry. MATERIAL AND METHODS: We conducted a retrospective study with 58 irradiated patients that received dental implant restorations before undergoing radiation treatment for HNC. The radiological success rate and the peri-implant bone resorption values were measured radiographically at 1 and 3 years after radiotherapy. Patients with no implants matching tumor site and stage served as a control group (n = 58). RESULTS: The median implant-bed-specific radiation dose was 40.3 Gy, which was significantly lower than tumor bed 62.4 Gy. An implant-bed-specific radiation dose higher than 40.0 Gy showed a significantly decreased radiologic success rate when compared to lower doses. Finally, evaluation of the radiation treatment plans revealed similar radiation hot spots in the test group of patients with implants and those of the control group. CONCLUSION: Our study confirms that radiotherapy negatively worsens peri-implant bone resorption, especially for implant-bed-specific dose more than 40 Gy, and the presence of implants within the radiation fields does not alter radiation dosimetry. The findings could be clinically informative to both surgeons and radio-oncologists. CLINICAL RELEVANCE: The interactions between radiotherapy and implants placed prior to radiotherapy treatment remain a largely unexplored topic. Based on the analysis of 3-dimensional modulated radiation plans, this study demonstrates the impact of implant-bed-specific radiation dose on marginal bone resorption of implants placed pre-radiation and considers the influence of these implants on radiation dosimetry. REGISTRATION NUMBER: CHICTR2100051923: ( http://www.chictr.org.cn/usercenter.aspx ).

To B (Bone Morphogenic Protein-2) or Not to B (Bone Morphogenic Protein-2): Mesenchymal Stem Cells May Explain the Protein's Role in Osteosarcomagenesis.

Osteosarcoma (OS), a primary malignant bone tumor, stems from bone marrow-derived mesenchymal stem cells (BMSCs) and/or committed osteoblast precursors. Distant metastases, in particular pulmonary and skeletal metastases, are common in patients with OS. Moreover, extensive resection of the primary tumor and bone metastases usually leads to bone defects in these patients. Bone morphogenic protein-2 (BMP-2) has been widely applied in bone regeneration with the rationale that BMP-2 promotes osteoblastic differentiation of BMSCs. Thus, BMP-2 might be useful after OS resection to repair bone defects. However, the potential tumorigenicity of BMP-2 remains a concern that has impeded the administration of BMP-2 in patients with OS and in populations susceptible to OS with severe bone deficiency (e.g., in patients with genetic mutation diseases and aberrant activities of bone metabolism). In fact, some studies have drawn the opposite conclusion about the effect of BMP-2 on OS progression. Given the roles of BMSCs in the origination of OS and osteogenesis, we hypothesized that the responses of BMSCs to BMP-2 in the tumor milieu may be responsible for OS development. This review focuses on the relationship among BMSCs, BMP-2, and OS cells; a better understanding of this relationship may elucidate the accurate mechanisms of actions of BMP-2 in osteosarcomagenesis and thereby pave the way for clinically safer and broader administration of BMP-2 in the future. For example, a low dosage of and a slow-release delivery strategy for BMP-2 are potential topics for exploration to treat OS.

Curcumin in Osteosarcoma Therapy: Combining With Immunotherapy, Chemotherapeutics, Bone Tissue Engineering Materials and Potential Synergism With Photodynamic Therapy.

Osteosarcoma is a dominating malignant bone tumor with high mortality due to pulmonary metastases. Furthermore, because of the cancer cell erosion and surgery resection, osteosarcoma always causes bone defects, which means dysfunction and disfigurement are seldom inevitable. Although various advanced treatments (e.g. chemotherapy, immunotherapy, radiotherapy) are coming up, the 5-year survival rate for osteosarcoma with metastases is still dismal. In line with this, the more potent treatments for osteosarcoma are in high demand. Curcumin, a perennial herb, has been reportedly applied in the therapy of various types of tumors via different mechanisms. In vitro, it has also been reported that curcumin can inhibit the proliferation of osteosarcoma cell lines and can be used to repair bone defects. This seems curcumin is a promising candidate in osteosarcoma treatment. However, due to its congenital property like hydrophobicity, and low bioavailability, affecting its anticancer effect, clinical applications of curcumin are highly limited. To enhance its performance in cancer therapies, some synergist approaches with curcumin have emerged. The present review presents some prospective ones (i.e. combinations with immunotherapy, chemotherapeutics, bone tissue engineering, and biomaterials) applied in osteosarcoma treatment. Additionally, with the advancements of photodynamic therapy in cancer therapy, this review also prospects the combination of curcumin with photodynamic therapy in osteosarcoma treatment.

Identification and Description of a New Pathogen Causing Flower Dry Rot on Passiflora edulis in China.

Passiflora edulis Sims (passion fruit) is an economically important fruit crop. However, a new flower dry rot has occurred in orchards located in Zhanjiang, China, and has led to serious production loss. Its disease incidence is approximately 30 to 40%. A total of 221 isolates of Fusarium sp. were obtained from samples of three types of symptomatic flowers. Three representative single-spore isolates (PaB-1, PaB-2, and PaB-3) from each type were used for pathogenicity tests, multilocus phylogenetic analyses, and morphological descriptions. Pathogenicity tests of buds of 5-month-old P. edulis plants showed symptoms similar to those observed in nature, and Koch's postulates were achieved. By comparing 36 typical species from the FUSARIUM-ID database, multilocus phylogenetic analyses showed that the sequences of TEF1, RPB2, and ITS of these isolates belong to the Incarnatum clade of the F. incarnatum-equiseti species complex (FIESC-17-a) with an independent branch. Therefore, the pathogenic isolates were identified as F. pernambucanum (FIESC-17-a). Moreover, in this study, the conidial anastomosis tubes were first observed in the FIESC. This is the first report of flower dry rot on P. edulis caused by F. pernambucanum. Further studies should be performed to determine effective disease management strategies.

Low Dose BMP2-Doped Calcium Phosphate Graft Promotes Bone Defect Healing in a Large Animal Model.

Background: Bone grafts are in high demand due to the increase in the cases of bone defects mainly caused by trauma, old age, and disease-related bone damages. Tissue-engineered calcium phosphate (CaP) biomaterials match the major inorganic contents of bone, thereby could be the potential bone graft substitute. However, CaP-bone grafts lack the osteoinductivity that is vital for effective bone regeneration. In this study, we aimed to test the bone defect healing potential of biomimetically fabricated low dose BMP2-doped CaP (BMP2.BioCaP) grafts in a large animal model. Methods: Low dose BMP2 was doped internally (BMP2-int.BioCaP) or on the surface of CaP (BMP2-sur.BioCaP) grafts during the fabrication process. Our previous study showed the robust bone regenerative potential of BMP2-int.BioCaP and BMP2-sur.BioCaP grafts in the rat ectopic model. In this study, we investigated the bone defect healing potential of BMP2.BioCaP grafts in sheep humerus/femoral defects, as well as compared with that of autologous bone graft and clinically used deproteinized bovine bone (DBB) xenograft. Results: Different ways of BMP2 doping did not affect the surface morphology and degradation properties of the graft materials. Micro-CT and histology results showed robustly higher bone defect-healing potential of the BMP2.BioCaP grafts compared to clinically used DBB grafts. The bone defect healing potential of BMP2.BioCaP grafts was as effective as that of the autologous bone graft. Although, BMP2-int.BioCaP doped half the amount of BMP2 compared to BMP2-sur.BioCaP, its' bone defect healing potential was even robust. The BMP2.BioCaP grafts showed less immunogenicity compared to BioCaP or DBB grafts. The volume density of blood vessel-like and bone marrow-like structures in both BMP2.BioCaP graft groups were in a similar extent to the autologous group. Meticulous observation of higher magnification histological images showed active bone regeneration and remodeling during bone defect healing in BMP2.BioCaP graft groups. Conclusion: The robust bone regenerative potential of BMP2.BioCaP grafts in the ectopic model and in-situ bone defects in small and large animals warrant the pre-clinical studies on large animal critical-sized segmental bone defects.

Dose Effects of Slow-Released Bone Morphogenetic Protein-2 Functionalized ß-Tricalcium Phosphate in Repairing Critical-Sized Bone Defects.

The aim of this study is to investigate the efficacy and the effect of the dosage of the slow-released Escherichia coli-derived recombinant human bone morphogenetic protein 2 (ErhBMP-2) functionalized ß-tricalcium phosphate (ß-TCP) in repairing critical-sized bone defects. The functionalization was implemented by modifying the surface of ß-TCP with biomimetic calcium phosphate coating with or without ErhBMP-2. Critical-sized calvarial defects were created in rats and filled with ErhBMP-2 functionalized ß-TCP loaded with gradient doses of ErhBMP-2 (0, 50, 100, 150, 200, and 300 µg/g). The blank control group and the autologous bone group were also included. The systemic toxicity was evaluated using routine blood and histopathological examination. The efficiency in bone healing was evaluated using microcomputed tomography, histology, and histometric analyses. Neither local nor systemic adverse effects were found following the implantation of the ErhBMP-2 functionalized ß-TCP. The new bone formation was significantly increased in the ErhBMP-2 functionalized ß-TCP groups compared with the blank group and the ß-TCP with coating only group. The efficacy of the ErhBMP-2 functionalized ß-TCP in bone healing was comparable to that of the autologous bone. There was no significant difference in bone formation among all concentrations of ErhBMP-2 (0-300 µg/g). Increased bone maturation was found in the higher concentration groups (150, 200, and 300 µg/g) when compared with the lower concentration groups (50, and 100 µg/g). Our results demonstrated that the ErhBMP-2 functionalized ß-TCP could significantly promote bone repairing in critical-sized defects, and it could clinically be a promising substitute for autologous bone. Besides, our results demonstrated that there was a dosage-dependent effect of ErhBMP-2 functionalized ß-TCP on bone maturation rather than bone formation. The optimized concentrations of ErhBMP-2 recommended for this kind of model should be in the range of 150-300 µg/g. Impact Statement Bone substitutes functionalized by mammalian-derived recombinant human bone morphogenetic protein 2 (rhBMP-2) have demonstrated to be comparable to the autologous bone in repairing the critical-sized bone defects. To develop a commercial product with more effective cost, Escherichia coli-derived rhBMP-2 (ErhBMP-2) has been produced and evaluated as an alternative to the mammalian-derived rhBMP-2. In this study, we prepared gradient ErhBMP-2 functionalized ß-tricalcium phosphate (ß-TCP) with biomimetic calcium phosphate coating and investigate their efficacy and dose effects. We revealed the dose effects of the slow-released ErhBMP-2 and demonstrated that ErhBMP-2 functionalized ß-TCP could be a promising bone substitute for bone regeneration in clinical settings.

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

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.

Periodontal regeneration using bone morphogenetic protein 2 incorporated biomimetic calcium phosphate in conjunction with barrier membrane: A pre-clinical study in dogs.

AIM: To evaluate the effect of bone morphogenetic protein 2 (BMP-2) incorporated biomimetic calcium phosphate (BMP-2/BioCaP) in conjunction with barrier membrane on periodontal regeneration in chronic periodontitis experimental model. MATERIAL AND METHODS: Chronic periodontitis experimental model with critical-sized supra-alveolar defects was created in 15 dogs' mandibles. After the initial periodontal therapy, the defects were randomly assigned to the following groups: (a) control; (b) barrier membrane; (c) deproteinized bovine bone mineral + barrier membrane; (d) BioCaP + barrier membrane and (e) BMP-2/BioCaP + barrier membrane (6 quadrants with 18 teeth per group). Eight weeks later, clinical examinations, micro-CT, and histomorphometric analyses were performed. RESULTS: Clinical examinations, including plaque index, bleeding index, and probing depth, were similar for all groups. In contrast, the clinical attachment loss was significantly lower in defects grafted with BMP-2/BioCaP and barrier membrane. The micro-CT results showed that the height of mineralized tissue in defects grafted with BMP-2/BioCaP and barrier membrane was significantly higher. For histometric analysis, the defects grafted with BMP-2/BioCaP and barrier membrane exhibited significantly more connective tissue height, new cementum height, new bone height and area, as well as less down-growth of junctional epithelium. CONCLUSION: BMP-2/BioCaP could be a promising bone substitute for periodontal regeneration.

A dual functional bone-defect-filling material with sequential antibacterial and osteoinductive properties for infected bone defect repair.

Infected bone defect healing is hindered by infection and compromised bone regenerative capacity. In this study, we designed a dual functional bone-defect-filling material with a sequential release system, that is, a burst release of a potent antibacterial agent, hydroxypropyltrimethyl ammonium chloride chitosan (HACC), followed by a controlled release of osteoinductive bone morphogenic protein (BMP2) to repair the infected bone defect. Minimum bactericidal concentration (MBC) of HACC against methicillin-resistant Staphylococcus aureus was 40 µg/mL. HACC at 40 µg/mL did not affect preosteoblast proliferation and did not influence the BMP2-induced alkaline phosphatase activity, osteocalcin expression, and matrix mineralization. in vitro release profile revealed burst release of HACC followed by a slow release of BMP2. in vivo bone formation was observed only in the BMP2-containing groups. HACC did not influence of biomimetic calcium phosphate (BioCaP) resorption and BMP2-induced bone formation. In conclusion, the optimized HACC/BMP2-incorporated BioCaP complex showed strong antibacterial effect and robustly enhanced osteoinduction both in vitro and in vivo.