Repair of alveolar clefts with recombinant human bone morphogenetic protein (rhBMP-2) in patients with clefts

Efficacy of Demineralized Bone Matrix for Revision Alveolar Bone Grafting in Patients Previously Treated with Bone Morphogenetic Protein 2 (BMP-2)

OBJECTIVE

This study investigates the effectiveness of demineralized bone matrix (DBX) to close alveolar clefts in patients previously treated with bone morphogenic protein-2 (BMP-2) who remained with bone nonunion.

DESIGN

This is an IRB-approved retrospective, single-center study.

SETTING

This study was conducted at a tertiary academic center.

PATIENTS/PARTICIPANTS

We searched for all surgical encounters with the Current Procedural Terminology (CPT) code 42210 from the years 2013-2019. Included patients were diagnosed with cleft alveolus, previous BMP-2 exposure and required revision bone grafting during mixed dentition for persistent alveolar defects.

INTERVENTIONS

17 patients underwent revision alveolar bone grafting (ABG) with either DBX (n = 10) or autograft (n = 7) to repair persistent bony cleft.

MAIN OUTCOME MEASURE(S)

The primary study outcome measured was alveolar bone graft revision failure described as continued alveolar nonunion.

RESULTS

The median age at revision ABG was 13.1 ± 3.3 years, with a mean follow-up time of 4.9 years (1.1-9.2 years). Patients were 53% male, 47% had a unilateral cleft lip and alveolus. 58.8% of patients were treated with DBX in the cleft, 41.2% treated with autograft from iliac crest. Overall, 11.8% (n = 2) of all revisions failed, requiring a second revision. The average time to reoperation was 2.06 years, and both were re-grafted with autograft. There was no statistically significant difference between the type of bone graft source used and the failure rate obtained (P = .1544).

CONCLUSIONS

DBX and autologous iliac crest bone grafts achieve similar alveolar union rates during revision ABG in patients treated with previous BMP-2 to the alveolar cleft.

Application of BMP-2 and its gene delivery vehicles in dentistry

The restoration of bone defects resulting from tooth loss, periodontal disease, severe trauma, tumour resection and congenital malformations is a crucial task in dentistry and maxillofacial surgery. Growth factor- and gene-activated bone graft substitutes can be used instead of traditional materials to solve these problems. New materials will overcome the low efficacy and difficulties associated with the use of traditional bone substitutes in complex situations. One of the most well-studied active components for bone graft substitutes is bone morphogenetic protein-2 (BMP-2), which has strong osteoinductive properties. The aim of this review was to examine the use of BMP-2 protein and gene therapy for bone regeneration in the oral and maxillofacial region and to discuss its future use.

A Survey of Bone Grafting Practice Patterns in North American Cleft Surgeons

INTRODUCTION

Alveolar bone grafting aims to restore bony continuity of the alveolus and provide optimal periodontal support for teeth adjacent to the cleft. We created a survey of cleft surgeons to assess the current standard of care regarding this procedure.

METHODS

A multiple choice survey was implemented using Qualtrics software and emailed to a list of 708 surgeons from the ACPA membership directory. Correlation between various provider factors and treatment practices was assessed with Fisher's exact test and likelihood ratio tests.

RESULTS

The response rate was 17.5%. Eighty-seven percent of providers preferred to perform grafts prior to secondary canine eruption while 10% favored before central incisor eruption. Eighty-one percent favored palatal expansion prior to bone grafting. Wide variability existed regarding the time to initiate postoperative orthodontics; 43% waited 4 to 6 months. Sixty-four percent of surgeons now utilize cone beam CT to assess graft take. The majority of respondents utilized cancellous bone autograft (92%) from the anterior iliac crest (97%) as graft material. Seventy percent used three or more modalities for post-operative pain control management. Early career surgeons (0-5 years) appeared more likely to use non-autologous materials (p < .01) for grafting.

CONCLUSION

Alveolar bone grafting prior to secondary canine eruption remains the most common strategy but other protocols are employed. Surgeons utilize multiple modalities for radiographic evaluation and most often use autologous cancellous bone as the primary grafting material. There is no true consensus on the perioperative timing and sequencing of orthodontic manipulation while principles of multimodal perioperative pain control appear widely accepted.

Current Status of Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) in Maxillofacial Surgery: Should It Be Continued?

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has shown potential in maxillofacial surgery owing to its osteoinductive properties. However, concerns about its safety and high cost have limited its widespread use. This review presents the status of rhBMP-2 use in maxillofacial surgery, focusing on its clinical application, efficacy, safety, and limitations. Studies have demonstrated rhBMP-2's potential to reduce donor site morbidity and increase bone height in sinus and ridge augmentation; however, it may not outperform autogenous bone grafts. In medication-related osteonecrosis of the jaw treatment, rhBMP-2 has been applied adjunctively with promising results, although its long-term safety requires further investigation. However, in maxillofacial trauma, its application is limited to the restoration of large defects. Safety concerns include postoperative edema and the theoretical risk of carcinogenesis. Although postoperative edema is manageable, the link between rhBMP-2 and cancer remains unclear. The limitations include the lack of an ideal carrier, the high cost of rhBMP-2, and the absence of an optimal dosing regimen. In conclusion, rhBMP-2 is a promising graft material for maxillofacial surgery. However, it has not yet become the gold standard owing to safety and cost concerns. Further research is required to establish long-term safety, optimize dosing, and develop better carriers.

Regeneration of Critical-Sized Mandibular Defects Using 3D-Printed Composite Scaffolds: A Quantitative Evaluation of New Bone Formation in In Vivo Studies

Mandibular tissue engineering aims to develop synthetic substitutes for the regeneration of critical size defects (CSD) caused by a variety of events, including tumor surgery and post-traumatic resections. Currently, the gold standard clinical treatment of mandibular resections (i.e., autologous fibular flap) has many drawbacks, driving research efforts toward scaffold design and fabrication by additive manufacturing (AM) techniques. Once implanted, the scaffold acts as a support for native tissue and facilitates processes that contribute to its regeneration, such as cells infiltration, matrix deposition and angiogenesis. However, to fulfil these functions, scaffolds must provide bioactivity by mimicking natural properties of the mandible in terms of structure, composition and mechanical behavior. This review aims to present the state of the art of scaffolds made with AM techniques that are specifically employed in mandibular tissue engineering applications. Biomaterials chemical composition and scaffold structural properties are deeply discussed, along with strategies to promote osteogenesis (i.e., delivery of biomolecules, incorporation of stem cells, and approaches to induce vascularization in the constructs). Finally, a comparison of in vivo studies is made by taking into consideration the amount of new bone formation (NB), the CSD dimensions, and the animal model.

Enhanced Biocompatibility and Osteogenic Activity of Marine-Plankton-Derived Whitlockite Bone Granules through Bone Morphogenetic Protein 2 Incorporation

Whitlockite (WH) is a calcium-phosphate-based Mg-containing ceramic with good mechanical properties, rapid resorption, and good osteogenicity. Recently, we successfully synthesized highly porous WH granules using a marine plankton exoskeleton (MP-WH). In the present study, we improved the osteoinductive activity of MP-WH granules by bone morphogenetic protein2 (BMP2) (MP-WH/BMP2). The surface morphology and composition of the fabricated MP-WH/BMP2 granules were characterized using scanning electron microscopy (SEM), X-ray diffraction, and Fourier transform infrared (FT-IR) spectroscopy. The biocompatibility and osteogenic effects were evaluated using human mesenchymal stem cells (hMSCs). BMP2 was absorbed on the surfaces of the MP-WH/BMP2 granules. Immobilized BMP2 was released at a moderate rate over 30 days. hMSCs seeded on MP-WH/BMP2 granules became biocompatible, with a better proliferation and adhesion for MP-WH/BMP2, compared with MP-WH. Bone-specific markers Runx2, type I collagen, osteocalcin, and osteopontin were significantly upregulated following BMP2 incorporation. Similar observations were made regarding the alkaline phosphatase activity. This study suggests that BMP2 incorporation improves the osteoinductive activity of marine-plankton-derived WH granules for bone tissue repair.

Stem Cells-Loaded 3D-Printed Scaffolds for the Reconstruction of Alveolar Cleft

The advances in the field of tissue engineering and regenerative medicine have opened new vistas for the repair of alveolar clefts. However, the currently available biomaterials used for the repair of alveolar clefts have poor mechanical properties and biocompatibility, which hinders the treatment outcomes. Here, we aimed to develop 3D printed biomimetic scaffolds that fuses β-tricalcium phosphate (β-TCP) and bone marrow mesenchymal stem cells (BMSCs) for improving the repair of alveolar clefts. The methacrylate gelatin (GelMA) was mixed with β-TCP for the preparation of GelMA/β-TCP hybrid scaffolds via 3D printing platform and chemically cross-linking with UV light. The physicochemical properties of the hydrogel scaffolds were characterized. Moreover, the survival state, proliferation ability, morphological characteristics, and osteogenic induction of BMSCs were examined. The prepared hybrid scaffolds showed good biocompatibility and mechanical properties. BMSCs attached well to the scaffolds and proliferated, survived, differentiated, and stimulated osteogenesis for the reconstruction of alveolar clefts. We expect that use of the prepared hybrid hydrogel scaffold can improve the outcomes of alveolar cleft repair in clinic and expand the application of hybrid hydrogel in tissue engineering repair.

Efficacy of regenerative medicine for alveolar cleft reconstruction: A systematic review and meta-analysis

Objective:

Objective: To analyze the efficacy and complications of regenerative medicine compared to autogenous bone graft for alveolar cleft reconstruction.

Method:

Method: Electronic search was done in PubMed, Scopus, Embase and Cochrane database for studies published until May 2021. No limitations were considered for the type of the included studies. The risk of bias (ROB) of the studies was assessed using the Cochrane Collaborations and NIH quality assessment tool. Meta-analyses were performed to assess the difference in the amount of bone formation and rate of complications. Grading of Recommendations, Assessment, Development and Evaluation (GRADE) was used for analyzing the level of the evidence.

Results:

Results: Among a total of 42 included studies, 21 studies used growth factors, 16 studies delivered cells, and five studies used biomaterials for bone regeneration of the alveolar cleft. Results showed no significant difference in the amount of bone formation between bone morphogenic protein-2 and iliac graft treated patients after six months (P=0.44) and 12 months (P=0.17) follow-up. Besides, higher swelling (OR=9.46,P<0.01) and less infection (OR=0.19,P=0.01) observed in BMP treated patients. Using stem cells can reduce the post-treatment pain (OR=0.04,P=0.01) but it has no significant impact on other complications (P>0.05). Using tissue engineering methods reduced the operation time (SD=1.06,P<0.01). GRADE assessment showed that results regarding the amount of bone formation volume after six and 12 months have low level of evidence.

Conclusion:

Conclusion: Tissue engineering methods can provide a comparable amount of bone formation as of the autogenous graft and reduce some of the complications, operation time and hospitalization duration.

Potential of Bone-Marrow-Derived Mesenchymal Stem Cells for Maxillofacial and Periodontal Regeneration: A Narrative Review

Bone-marrow-derived mesenchymal stem cells (BM-MSCs) are one of the most widely studied postnatal stem cell populations and are considered to utilize more frequently in cell-based therapy and cancer. These types of stem cells can undergo multilineage differentiation including blood cells, cardiac cells, and osteogenic cells differentiation, thus providing an alternative source of mesenchymal stem cells (MSCs) for tissue engineering and personalized medicine. Despite the ability to reprogram human adult somatic cells to induced pluripotent stem cells (iPSCs) in culture which provided a great opportunity and opened the new door for establishing the in vitro disease modeling and generating an unlimited source for cell base therapy, using MSCs for regeneration purposes still have a great chance to cure diseases. In this review, we discuss the important issues in MSCs biology including the origin and functions of MSCs and their application for craniofacial and periodontal tissue regeneration, discuss the potential and clinical applications of this type of stem cells in differentiation to maxillofacial bone and cartilage in vitro, and address important future hopes and challenges in this field.

Bone Regeneration of a 3D-Printed Alloplastic and Particulate Xenogenic Graft with rhBMP-2

This study aimed to evaluate the bone regeneration capacity of a customized alloplastic material and xenograft with recombinant human bone morphogenetic protein-2 (rhBMP-2). We prepared hydroxyapatite (HA)/tricalcium phosphate (TCP) pure ceramic bone blocks made using a 3D printing system and added rhBMP-2 to both materials. In eight beagle dogs, a total of 32 defects were created on the lower jaws. The defective sites of the negative control group were left untreated (N group; 8 defects), and those in the positive control group were filled with particle-type Bio-Oss (P group; 12 defects). The defect sites in the experimental group were filled with 3D-printed synthetic bone blocks (3D group; 12 defects). Radiographic and histological evaluations were performed after healing periods of 6 and 12 weeks and showed no significant difference in new bone formation and total bone between the P and 3D groups. The 3D-printed custom HA/TCP graft with rhBMP-2 showed bone regeneration effects similar to that of particulate Bio-Oss with rhBMP-2. Through further study and development, the application of 3D-printed customized alloplastic grafts will be extended to various fields of bone regeneration.

The 25 Most Cited Articles in The Journal of Craniofacial Surgery: A Study Based on the Web of Science From 1995 to 2020

ABSTRACT

The aim of this study was to identified and analyzed the top 25 most cited articles among the articles published in The Journal of Craniofacial Surgery (J Craniofac Surg) from 1995 to 2020 in the Web of Science database. Using the advanced search section in the Web of Science, all articles published in the J Craniofac Surg were listed. The distribution of the numbers of publications by years was determined. It was determined that a total of 11,888 articles were published in the J Craniofac Surg between 1995 and 2020. A total of 84,218 citations were made to these articles, and the h-index of these articles was 73. The top 25 most cited articles were determined. The top three countries that made the most cited to these 25 articles were the USA (n: 1112), China (n: 292), and Germany (n: 251), respectively. The top three journals that made the most cited to these 25 articles were the J Craniofac Surg (n: 378), Plast Reconstr Surg (n: 179), and J Oral Maxillofac Surg (n: 120), respectively. The authors think that this study may benefit researchers in this field by identifying the most cited articles in the J Craniofac Surg.

Bone Grafting of Alveolar Clefts

The goals of alveolar cleft repair include (1) stabilization of the maxilla, (2) permitting tooth eruption, (3) eliminating the oronasal fistula, (4) improving aesthetics, and (5) improving speech. Alveolar cleft repair should be considered one of the steps of a larger comprehensive orthodontic management plan. In conjunction with closure of the oronasal fistula, a variety of grafting materials can be used in the alveolar cleft. Autogenous grafts have been found to have greater efficacy compared with allogenic or xenogeneic bone, substitute bone, and alloplasts but with more donor site morbidity.

Maxillofacial Bone Grafting Materials: 2021 Update

For successful outcomes in bone grafting, it is important to have a clear and detailed understanding of the fundamentals and basics in regenerative science. This article summarize the grafting materials and growth factors that are now in use to provide an improved understanding of the properties of each material and indications for subsequent use. The article gives an overview of the fundamentals of bone healing, including the physiology of regeneration. It is hoped that clinicians can make improved decisions that are based in literature when considering treatment options for restoring patients' functional dentition.

Autogenous Iliac Crest Versus rhBMP-2 for Alveolar Cleft Grafting: A 14-Year Single-Institution Experience

PURPOSE

This study sought to compare radiographic outcomes and resource utilization between recombinant human bone morphogenetic protein-2 (rhBMP-2) and anterior iliac crest bone graft (AICBG) when used for secondary alveolar grafting.

MATERIALS AND METHODS

This is a 14-year retrospective study of patients with alveolar clefts treated at the Morgan Stanley Children's Hospital of New York-Presbyterian/Columbia University Irving Medical Center between January 2006 and January 2020. Patients who had alveolar grafting with either rhBMP-2 or AICBG were included in this study. The primary study predictor was the graft material. The study outcomes were bone height, operating room time, and the number of scrubbed personnel (surgeon and assistants). Graft survival was measured at a minimum of 6 months postoperatively. Bone height was scored according to the Bergland scale, and radiographic success was defined as Bergland types 1 or 2.

RESULTS

The study sample included a total of 115 patients with 130 alveolar clefts. Overall, 13.0% of patients had bilateral repairs, and 17.4% were retreatments. The cumulative success rate was 89.5%. There were no differences in success between materials (rhBMP: 90.3%; AICBG: 89.1%; P = .85). Patients presenting for retreatment were more likely to receive rhBMP-2 than AICBG (48.6 vs 3.8%, P < .01). After controlling for other significant confounders, the rhBMP-2 group required less personnel (P < .01) and operating room time (P < .01). Only 1 patient in the rhBMP-2 group was admitted, whereas all AICBG patients were admitted a minimum of 1 night.

CONCLUSIONS

Compared with AICBG, rhBMP-2 produced a similar height of bone but required less hospital resources. The decision to use harvested ilium or rhBMP-2 is not limited by outcome data at this time. More studies will need to be performed to identify the particular advantages of each graft material. The choice of material is currently both surgeon specific and patient specific and requires thorough informed consent.

Three-Dimensional Printing for Craniofacial Bone Tissue Engineering

The basic concepts from the fields of biology and engineering are integrated into tissue engineering to develop constructs for the repair of damaged and/or absent tissues, respectively. The field has grown substantially over the past two decades, with particular interest in bone tissue engineering (BTE). Clinically, there are circumstances in which the quantity of bone that is necessary to restore form and function either exceeds the patient's healing capacity or bone's intrinsic regenerative capabilities. Vascularized osseous or osteocutaneous free flaps are the standard of care with autologous bone remaining the gold standard, but is commonly associated with donor site morbidity, graft resorption, increased operating time, and cost. Regardless of the size of a craniofacial defect, from trauma, pathology, and osteonecrosis, surgeons and engineers involved with reconstruction need to consider the complex three-dimensional (3D) geometry of the defect and its relationship to local structures. Three-dimensional printing has garnered significant attention and presents opportunities to use craniofacial BTE as a technology that offers a personalized approach to bony reconstruction. Clinicians and engineers are able to work together to produce patient-specific space-maintaining scaffolds tailored to site-specific defects, which are osteogenic, osseoconductive, osseoinductive, encourage angiogenesis/vasculogenesis, and mechanically stable upon implantation to prevent immediate failure. In this work, we review biological and engineering principles important in applying 3D printing technology to BTE for craniofacial reconstruction as well as present recent translational advancements in 3D printed bioactive ceramic scaffold technology.

Innovative Molecular and Cellular Therapeutics in Cleft Palate Tissue Engineering

Clefts of the lip and/or palate are the most prevalent orofacial birth defects occurring in about 1:700 live human births worldwide. Early postnatal surgical interventions are extensive and staged to bring about optimal growth and fusion of palatal shelves. Severe cleft defects pose a challenge to correct with surgery alone, resulting in complications and sequelae requiring life-long, multidisciplinary care. Advances made in materials science innovation, including scaffold-based delivery systems for precision tissue engineering, now offer new avenues for stimulating bone formation at the site of surgical correction for palatal clefts. In this study, we review the present scientific literature on key developmental events that can go awry in palate development and the common surgical practices and challenges faced in correcting cleft defects. How key osteoinductive pathways implicated in palatogenesis inform the design and optimization of constructs for cleft palate correction is discussed within the context of translation to humans. Finally, we highlight new osteogenic agents and innovative delivery systems with the potential to be adopted in engineering-based therapeutic approaches for the correction of palatal defects. Impact statement Tissue-engineered scaffolds supplemented with osteogenic growth factors have attractive, largely unexplored possibilities to modulate molecular signaling networks relevant to driving palatogenesis in the context of congenital anomalies (e.g., cleft palate). Constructs that address this need may obviate current use of autologous bone grafts, thereby avoiding donor-site morbidity and other regenerative challenges in patients afflicted with palatal clefts. Combinations of biomaterials and drug delivery of diverse regenerative cues and biologics are currently transforming strategies exploited by engineers, scientists, and clinicians for palatal cleft repair.

Deciduous Dental Pulp Stem Cells for Maxillary Alveolar Reconstruction in Cleft Lip and Palate Patients

Background

To reduce morbidity to cleft patients, new approaches have been developed and here, we report for the first time the use of deciduous dental pulp stem cells (DDPSC) associated with a hydroxyapatite-collagen sponge (Bio-Oss Collagen® 250 mg, Geistlich) for closing alveolar defects during secondary dental eruption, further comparing these results to historical controls.

Methods

Six patients, aged 8 to 12, were selected. Autologous DDPSC were isolated from each patient, then associated with the biomaterial and this bone tissue engineered set was used to fill the alveolar defect. Computed tomography was performed to assess both preoperative and 6- and 12-month postoperative outcomes. Overall morbidity was recorded. Historical controls consisted of sixteen patients previously selected and randomly assigned to group one (rhBMP-2) or group two (iliac crest bone graft).

Results

DDPSC could be isolated and characterized as mesenchymal stem cells. Progressive alveolar bone union has occurred in all patients. Similarly to group two 75.4%, SD ± 4.0, p > 0.999, but statistically different from group one (59.6%, SD ± 9.9, p > 0.999, but statistically different from group one (59.6%, SD ± 9.9.

Conclusion

For this selected group of patients, DDPSC therapy resulted in satisfactory bone healing with excellent feasibility and safety, which adds significantly to the prospect of stem cell use in clinical settings. Clinical Question/Level of Evidence. Therapeutic, II. This trial is registered with https://clinicaltrials.gov/ct2/show/NCT01932164?term=NCT01932164&rank=1.

Extracellular Matrix Composition and Remodeling: Current Perspectives on Secondary Palate Formation, Cleft Lip/Palate, and Palatal Reconstruction

Craniofacial development comprises a complex process in humans in which failures or disturbances frequently lead to congenital anomalies. Cleft lip with/without palate (CL/P) is a common congenital anomaly that occurs due to variations in craniofacial development genes, and may occur as part of a syndrome, or more commonly in isolated forms (non-syndromic). The etiology of CL/P is multifactorial with genes, environmental factors, and their potential interactions contributing to the condition. Rehabilitation of CL/P patients requires a multidisciplinary team to perform the multiple surgical, dental, and psychological interventions required throughout the patient's life. Despite progress, lip/palatal reconstruction is still a major treatment challenge. Genetic mutations and polymorphisms in several genes, including extracellular matrix (ECM) genes, soluble factors, and enzymes responsible for ECM remodeling (e.g., metalloproteinases), have been suggested to play a role in the etiology of CL/P; hence, these may be considered likely targets for the development of new preventive and/or therapeutic strategies. In this context, investigations are being conducted on new therapeutic approaches based on tissue bioengineering, associating stem cells with biomaterials, signaling molecules, and innovative technologies. In this review, we discuss the role of genes involved in ECM composition and remodeling during secondary palate formation and pathogenesis and genetic etiology of CL/P. We also discuss potential therapeutic approaches using bioactive molecules and principles of tissue bioengineering for state-of-the-art CL/P repair and palatal reconstruction.

Dipyridamole-loaded 3D-printed bioceramic scaffolds stimulate pediatric bone regeneration in vivo without disruption of craniofacial growth through facial maturity

This study investigates a comprehensive model of bone regeneration capacity of dypiridamole-loaded 3D-printed bioceramic (DIPY-3DPBC) scaffolds composed of 100% beta-tricalcium phosphate (β -TCP) in an immature rabbit model through the time of facial maturity. The efficacy of this construct was compared to autologous bone graft, the clinical standard of care in pediatric craniofacial reconstruction, with attention paid to volume of regenerated bone by 3D reconstruction, histologic and mechanical properties of regenerated bone, and long-term safety regarding potential craniofacial growth restriction. Additionally, long-term degradation of scaffold constructs was evaluated. At 24 weeks in vivo, DIPY-3DPBC scaffolds demonstrated volumetrically significant osteogenic regeneration of calvarial and alveolar defects comparable to autogenous bone graft with favorable biodegradation of the bioactive ceramic component in vivo. Characterization of regenerated bone reveals osteogenesis of organized, vascularized bone with histologic and mechanical characteristics comparable to native bone. Radiographic and histologic analyses were consistent with patent craniofacial sutures. Lastly, through application of 3D morphometric facial surface analysis, our results support that DIPY-3DPBC scaffolds do not cause premature closure of sutures and preserve normal craniofacial growth. Based on this novel evaluation model, this DIPY-3DPBC scaffold strategy is a promising candidate as a safe, efficacious pediatric bone tissue engineering strategy.

Regeneration of a Pediatric Alveolar Cleft Model Using Three-Dimensionally Printed Bioceramic Scaffolds and Osteogenic Agents: Comparison of Dipyridamole and rhBMP-2

BACKGROUND

Alveolar clefts are traditionally treated with secondary bone grafting, but this is associated with morbidity and graft resorption. Although recombinant human bone morphogenetic protein-2 (rhBMP-2) is under investigation for alveolar cleft repair, safety concerns remain. Dipyridamole is an adenosine receptor indirect agonist with known osteogenic potential. This study compared dipyridamole to rhBMP-2 at alveolar cleft defects delivered using bioceramic scaffolds.

METHODS

Skeletally immature New Zealand White rabbits underwent unilateral, 3.5 × 3.5-mm alveolar resection adjacent to the growing suture. Five served as negative controls. The remaining defects were reconstructed with three-dimensionally printed bioceramic scaffolds coated with 1000 μm of dipyridamole (n = 6), 10,000 μm of dipyridamole (n = 7), or 0.2 mg/ml of rhBMP-2 (n = 5). At 8 weeks, new bone was quantified. Nondecalcified histologic evaluation was performed, and new bone was evaluated mechanically. Statistical analysis was performed using a generalized linear mixed model and the Wilcoxon rank sum test.

RESULTS

Negative controls did not heal, whereas new bone formation bridged all three-dimensionally printed bioceramic treatment groups. The 1000-μm dipyridamole scaffolds regenerated 28.03 ± 7.38 percent, 10,000-μm dipyridamole scaffolds regenerated 36.18 ± 6.83 percent (1000 μm versus 10,000 μm dipyridamole; p = 0.104), and rhBMP-2-coated scaffolds regenerated 37.17 ± 16.69 percent bone (p = 0.124 versus 1000 μm dipyridamole, and p = 0.938 versus 10,000 μm dipyridamole). On histology/electron microscopy, no changes in suture biology were evident for dipyridamole, whereas rhBMP-2 demonstrated early signs of suture fusion. Healing was highly cellular and vascularized across all groups. No statistical differences in mechanical properties were observed between either dipyridamole or rhBMP-2 compared with native bone.

CONCLUSION

Dipyridamole generates new bone without osteolysis and early suture fusion associated with rhBMP-2 in skeletally immature bone defects.

Trends in Alveolar Bone Grafting and the Use of Recombinant Bone Morphogenetic Protein (RhBMP) in the United States

Objectives:

To gather information about current practices and assess the opinions, preferences, and clinical knowledge of surgeons who perform alveolar bone grafts. In addition, surgical training differences in correlation to techniques and outcomes are evaluated.

Methods:

A survey with both multiple choice and narrative answers regarding surgeons’ practices for alveolar bone grafting was designed and sent via email to members of the American Cleft Palate/Craniofacial Association (ACPA) identified as general craniofacial or oral maxillofacial surgeons. Responses were collected via an anonymous online survey tool.

Participants:

Members (336) of ACPA identified as craniofacial or oral-maxillofacial surgeons were contacted, and 62 responses were recorded.

Results:

The majority of survey respondents were oral-maxillofacial surgeons in practice for more than 15 years. 98.4% of respondents had used iliac crest and at least one additional source for grafting, while only 52.7% had performed grafting using recombinant bone morphogenetic protein (RhBMP). 82% used cone beam CT as their evaluation of choice for graft assessment and the majority (62.9%) waited more than 8 weeks postoperatively to image. Chi-square analysis demonstrated significantly longer time in practice for practitioners without craniofacial fellowship training.

Conclusions:

The results of this study demonstrate that there remains significant variation in alveolar bone grafting practices among surgeons. While some consensus exists, new innovations and technologies will require continued evaluation of surgical practices and outcomes. Long-term follow-up studies are needed especially with regard to the use of RhBMP in alveolar clefts.

Recombinant Human Bone Morphogenic Protein-2 Combined With Autogenous Bone Graft for Reconstruction of Alveolar Cleft

Recombinant human bone morphogenic proteins (rhBMPs) have been introduced for reconstruction of alveolar defects. The volume of the bone formed at the cleft region may be related to rhBMP-2 dose. Greater side effects have been reported with increased doses of rhBMP-2. The aim of the present study was to assess the bone at the cleft area using low dose of rhBMP-2 combined with autogenous bone graft for reconstruction of the alveolar cleft. Patients with unilateral cleft lip and palate between the 11 to 14 years old were enrolled. After palatal expansion, autogenous graft was placed at the side of cleft in the control group (n = 6). In the BMP group, the rhBMP-2 was injected into the autogenous bone graft at the defect site (n = 5). Cone beam computed tomography (CBCT) images were taken of all patients immediately and 3 months after graft surgery to compare the density, thickness, and height of the bone graft between the 2 groups. Intermolar and interpremolar widths were also measured. The authors found less diminish of density and height of the bone graft 3 months postsurgery in patients with autogenous bone graft combined with rhBMP-2. However, significant difference in the relapse tendency of transverse dimension of the arch or thickness of the bone graft was not observed between the 2 groups. Thus, low dose rhBMP-2 combined with autogenous bone graft can be promising to reach predictable results after alveolar reconstruction in cleft lip and palate patients.

The effects of NELL on corticotomy-assisted tooth movement and osteogenesis in a rat model

INTRODUCTION

Exogenous Nel-like molecule type 1 (NELL1) represents a potentially attractive clinical treatment option in the orthodontic and other settings because of its osteoinductive and vasculogenic properties.

AIMS

To explore effects of NELL1on corticotomy-assisted tooth movement and osteogenesis in a rat model.

METHODS

Thirty Sprague-Dawley rats were divided into 6 groups: Control, Sham, Tooth movement only, Vehicle, NELL1-LD (low-dose NELL), NELL1-HD (high-dose NELL). Human recombinant NELL1 protein was applied locally (Groups NELL1-LD and NELL1-HD) into buccal mucosa region of left first upper molar. Then the distance and velocity of tooth movement was measured, animals at 6 weeks after surgery were sacrificed, and was followed by computed tomography and histochemical staining.

RESULTS

Both NELL1 groups had higher bone mineral density, greater tooth movement distance and velocity in comparison to the Vehicle group. Proximally and distally, periodontal ligament width was significantly increased in the NELL1-LD and NELL1-HD groups. Decortication enhances remodeling, however, rapid bone formation by high-dose NELL1 may affect bone absorption.

CONCLUSION

Appropriate dose of NELL1 can be administrated to reduce the total time for tooth movement, and may shorten the treatment time in select populations.

Alternatives to Autologous Bone Graft in Alveolar Cleft Reconstruction: The State of Alveolar Tissue Engineering

Alveolar cleft reconstruction has historically relied on autologous iliac crest bone grafting (ICBG), but donor site morbidity, pain, and prolonged hospitalization have prompted the search for bone graft substitutes. The authors evaluated bone graft substitutes with the highest levels of evidence, and highlight the products that show promise in alveolar cleft repair and in maxillary augmentation. This comprehensive review guides the craniofacial surgeon toward safe and informed utilization of biomaterials in the alveolar cleft.A literature search was performed to identify in vitro human studies that fulfilled the following criteria: Level I or Level II of evidence, ≥30 subjects, and a direct comparison between a autologous bone graft and a bone graft substitute. A second literature search was performed that captured all studies, regardless of level of evidence, which evaluated bone graft substitutes for alveolar cleft repair or alveolar augmentation for dental implants. Adverse events for each of these products were tabulated as well.Sixteen studies featuring 6 bone graft substitutes: hydroxyapatite, demineralized bone matrix (DBM), β-tricalcium phosphate (TCP), calcium phosphate, recombinant human bone morphogenic protein-2 (rhBMP-2), and rhBMP7 fit the inclusion criteria for the first search. Through our second search, the authors found that DBM, TCP, rhBMP-2, and rhBMP7 have been studied most extensively in the alveolar cleft literature, though frequently in studies using less rigorous methodology (Level III evidence or below). rhBMP-2 was the best studied and showed comparable efficacy to ICBG in terms of volume of bone regeneration, bone density, and capacity to accommodate tooth eruption within the graft site. Pricing for products ranged from $290 to $3110 per 5 mL.The balance between innovation and safety is a complex process requiring constant vigilance and evaluation. Here, the authors profile several bone graft substitutes that demonstrate the most promise in alveolar cleft reconstruction.

Volumetric Cleft Changes in Treatment With Bone Morphogenic Protein/β-Tricalcium Phosphate Versus Grafts From the Iliac Crest or Symphysis

PURPOSE

To compare the volumetric changes in successfully treated clefts with secondary alveolar grafting using recombinant human bone morphogenic protein-2 (rhBMP-2) delivered in β-tricalcium phosphate (βTCP) scaffold versus autogenous grafts obtained from the iliac crest and mandibular symphysis.

PATIENTS AND METHODS

We performed a retrospective cohort study of cone-beam computed tomography scans of 25 subjects with unilateral or bilateral clefts. Of the 25 patients, 7 received an iliac crest bone graft, 9 received a mandibular symphyseal bone graft, and 9 subjects received the rhBMP-2/βTCP bone substitute. Volumetric rendering software was used to calculate the amount of new bone formation and residual bone defect present in the cleft area. The data were analyzed using Wilcoxon and Kruskal-Wallis tests and Pearson's correlation coefficient.

RESULTS

The mean percentage of new bone formation for the iliac crest, symphysis, and rhBMP-2/βTCP was 85.47, 80.56, and 81.22%, respectively (P = .0854). The initial cleft volume had a weak positive correlation with the percentage of new bone formation (r = 0.18), but the postoperative residual cleft volume had a strong negative correlation (r = 0.71).

CONCLUSIONS

rhBMP2 delivered in a βTCP scaffold in alveolar cleft patients can be a viable alternative to autogenous iliac crest and symphysis grafts, eliminating donor site morbidity.

Antibody-Mediated Osseous Regeneration for Bone Tissue Engineering in Canine Segmental Defects

Among many applications of therapeutic monoclonal antibodies (mAbs), a unique approach for regenerative medicine has entailed antibody-mediated osseous regeneration (AMOR). In an effort to identify a clinically relevant model of craniofacial defect, the present study investigated the efficacy of mAb specific for bone morphogenetic protein- (BMP-) 2 to repair canine segmental mandibular continuity defect model. Accordingly, a 15 mm unilateral segmental defect was created in mandible and fixated with a titanium plate. Anorganic bovine bone mineral with 10% collagen (ABBM-C) was functionalized with 25 μg/mL of either chimeric anti-BMP-2 mAb or isotype-matched mAb (negative control). Recombinant human (rh) BMP-2 served as positive control. Morphometric analyses were performed on computed tomography (CT) and histologic images. Bone densities within healed defect sites at 12 weeks after surgery were 1360.81 ± 10.52 Hounsfield Unit (HU), 1044.27 ± 141.16 HU, and 839.45 ± 179.41 HU, in sites with implanted anti-BMP-2 mAb, rhBMP-2, and isotype mAb groups, respectively. Osteoid bone formation in anti-BMP-2 mAb (42.99% ± 8.67) and rhBMP-2 (48.97% ± 2.96) groups was not significantly different but was higher (p < 0.05) than in sites with isotype control mAb (26.8% ± 5.35). In view of the long-term objective of translational application of AMOR in humans, the results of the present study demonstrated the feasibility of AMOR in a large clinically relevant animal model.

Development and Assessment of a 3D-Printed Scaffold with rhBMP-2 for an Implant Surgical Guide Stent and Bone Graft Material: A Pilot Animal Study

In this study, a new concept of a 3D-printed scaffold was introduced for the accurate placement of an implant and the application of a recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded bone graft. This preliminary study was conducted using two adult beagles to evaluate the 3D-printed polycaprolactone (PCL)/β-tricalcium phosphate (β-TCP)/bone decellularized extracellular matrix (bdECM) scaffold conjugated with rhBMP-2 for the simultaneous use as an implant surgical guide stent and bone graft material that promotes new bone growth. Teeth were extracted from the mandible of the beagle model and scanned by computed tomography (CT) to fabricate a customized scaffold that would fit the bone defect. After positioning the implant guide scaffold, the implant was placed and rhBMP-2 was injected into the scaffold of the experimental group. The two beagles were sacrificed after three months. The specimen block was obtained and scanned by micro-CT. Histological analysis showed that the control and experimental groups had similar new bone volume (NBV, %) but the experimental group with BMP exhibited a significantly higher bone-to-implant contact ratio (BIC, %). Within the limitations of this preliminary study, a 3D-printed scaffold conjugated with rhBMP-2 can be used simultaneously as an implant surgical guide and a bone graft in a large bone defect site. Further large-scale studies will be needed to confirm these results.

Off-Label Use of Bone Morphogenetic Protein 2 in the Reconstructions of Mandibular Continuity Defects

This paper describes 3 patients of off-label use of bone morphogenetic protein 2 (rhBMP-2) in the reconstruction of mandibular continuity defects. In the first patient, rhBMP-2 was associated with iliac crest bone graft for late mandibular reconstruction after resection of osteosarcoma. In the 2 other patients, rhBMP-2 was used alone. In 1 patient the mandibular continuity defect was due to resection for treatment of osteomyelitis and in the other patient a continuity defect was created by unsuccessful osteogenic distraction for correction of mandibular hypoplasia. Despite the good results in those patients, the off-label use of rhBMP-2 is associated with increased rate of complications, so more studies are needed to assess the predictability of the use of rhBMP-2 in mandibular continuity defects. Therefore, at the moment the off-label use of rhBMP-2 should be restricted to complicated bone defects in which the conventional alternatives of reconstruction were unsuccessful.

Collagen Sponge Functionalized with Chimeric Anti-BMP-2 Monoclonal Antibody Mediates Repair of Critical-Size Mandibular Continuity Defects in a Nonhuman Primate Model

Antibody-mediated osseous regeneration (AMOR) has been introduced by our research group as a tissue engineering approach to capture of endogenous growth factors through the application of specific monoclonal antibodies (mAbs) immobilized on a scaffold. Specifically, anti-Bone Morphogenetic Protein- (BMP-) 2 mAbs have been demonstrated to be efficacious in mediating bone repair in a number of bone defects. The present study sought to investigate the application of AMOR for repair of mandibular continuity defect in nonhuman primates. Critical-sized mandibular continuity defects were created in Macaca fascicularis locally implanted with absorbable collagen sponges (ACS) functionalized with chimeric anti-BMP-2 mAb or isotype control mAb. 2D and 3D analysis of cone beam computed tomography (CBCT) imaging demonstrated increased bone density and volume observed within mandibular continuity defects implanted with collagen scaffolds functionalized with anti-BMP-2 mAb, compared with isotype-matched control mAb. Both CBCT imaging and histologic examination demonstrated de novo bone formation that was in direct apposition to the margins of the resected bone. It is hypothesized that bone injury may be necessary for AMOR. This is evidenced by de novo bone formation adjacent to resected bone margins, which may be the source of endogenous BMPs captured by anti-BMP-2 mAb, in turn mediating bone repair.

Improving the Evaluation of Alveolar Bone Grafts with Cone Beam Computerized Tomography

Objective

Cone Beam computed tomography (CBCT) is used increasingly as a replacement for periapical x-rays when evaluating alveolar bone grafting. The manufacturer's standard settings for dental imaging may not, however, represent the optimal settings for evaluating postoperative alveolar bone grafts. We examined the influence of exposure parameters on CBCT image quality to optimize the quality of CBCT images while reducing the radiation dose to the minimum level necessary to obtain adequate images.

Methods

A defect was created in a cadaver head to simulate an alveolar cleft, and the area was filled with a synthetic material to simulate an alveolar bone graft. Serial CBCT scans were acquired, systematically varying tube voltage and tube current settings from 72 to 96kV and 3 to 12mA. Region of interest analysis was undertaken, and image quality was evaluated by comparing the ratios of native alveolar bone to soft tissue and the ratios of synthetic bone graft to soft tissue and by assessing image noise.

Results

Twenty-one CBCT data sets were obtained. Reducing tube voltage (kV) resulted in increased contrast ratio between bone and soft tissue and between synthetic bone graft and soft tissue, with maximal contrast at values of 76 kV/11 mA, 72 kV/12 mA, and 72 kV/11 mA. Of these, the setting with lowest image noise was 76 kV/11 mA. This setting also resulted in a radiation dose of less than half of the manufacturer's recommended settings for the same scan volume.

Conclusions

There is potential to improve CBCT image quality significantly while dramatically reducing the radiation dose during postoperative examinations for alveolar bone grafting in patients with cleft lip and palate.

Direct comparison of current cell-based and cell-free approaches towards the repair of craniofacial bone defects - A preclinical study

For craniofacial bone defect repair, several alternatives to bone graft (BG) exist, including the combination of biphasic calcium phosphate (BCP) biomaterials with total bone marrow (TBM) and bone marrow-derived mesenchymal stromal cells (MSCs), or the use of growth factors like recombinant human bone morphogenic protein-2 (RhBMP-2) and various scaffolds. Therefore, clinicians might be unsure as to which approach will offer their patients the most benefit. Here, we aimed to compare different clinically relevant bone tissue engineering methods in an "all-in-one" study in rat calvarial defects. TBM, and MSCs committed or not, and cultured in two- or three-dimensions were mixed with BCP and implanted in bilateral parietal bone defects in rats. RhBMP-2 and BG were used as positive controls. After 7 weeks, significant de novo bone formation was observed in rhBMP-2 and BG groups, and in a lesser amount, when BCP biomaterials were mixed with TBM or committed MSCs cultured in three-dimensions. Due to the efficacy and safety of the TBM/BCP combination approach, we recommend this one-step procedure for further clinical investigation.

STATEMENT OF SIGNIFICANCE

For craniofacial repair, total bone marrow (BM) and BM mesenchymal stem cell (MSC)-based regenerative medicine have shown to be promising in alternative to bone grafting (BG). Therefore, clinicians might be unsure as to which approach will offer the most benefit. Here, BM and MSCs committed or not were mixed with calcium phosphate ceramics (CaP) and implanted in bone defects in rats. RhBMP-2 and BG were used as positive controls. After 7 weeks, significant bone formation was observed in rhBMP-2 and BG groups, and when CaP were mixed with BM or committed MSCs. Since the BM-based procedure does not require bone harvest or cell culture, but provides de novo bone formation, we recommend consideration of this strategy for craniofacial applications.

Biomechanical analysis of engineered bone with anti-BMP2 antibody immobilized on different scaffolds

Recently we have demonstrated the ability of monoclonal antibodies (mAb) specific for bone morphogenetic protein (BMP)-2 immobilized on different scaffolds to mediate bone formation, a process referred to as Antibody Mediated Osseous Regeneration (AMOR). One of the key properties of regenerated bone is its biomechanical strength, in particular in load-bearing areas. This study sought to test the hypothesis that the biomechanical strength of regenerated bone depends of the mode of regeneration, as well as the scaffold used. Four different scaffolds, namely titanium granules (Ti), alginate hydrogel, anorganic bovine bone mineral (ABBM), and absorbable collagen sponge (ACS) were functionalized with anti-BMP-2 or isotype control mAb and implanted into rat critical-size calvarial defects. The morphology, density and strength of the regenerated bone were evaluated after 8 weeks. Results demonstrated that scaffolds functionalized with anti-BMP-2 mAb exhibited varying degrees of bone volume and density. Ti and ABBM achieved the highest bone volume, density, and strength of bone. When anti-BMP-2 mAb was immobilized on Ti or ABBM, the strength of the regenerated bone were 80% and 77% of native bone respectively, compared with 60% of native bone in sites implanted with rh-BMP-2. Control interventions with isotype mAb did not promote considerable bone regeneration and exhibited significantly lower mechanical properties. SEM analysis showed specimens immobilized with anti-BMP-2 mAb formed new bone with organized structure bridging the crack areas. Altogether, the present data demonstrated that the morphological and mechanical properties of bone bioengineered through AMOR could approximate that of native bone, when appropriate scaffolds are used. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1465-1473, 2016.

Regenerative medicine in the treatment of alveolar cleft defect: A systematic review of the literature

Despite a possible risk of donor site morbidity, autogenous bone grafting is considered the gold standard treatment for human alveolar cleft defect. Tissue engineering methods have recently been investigated with the aim of minimizing donor site morbidities. Here we systematically review the various tissue engineering methods applied to human alveolar cleft defects. An electronic search was conducted in the PubMed database up to March 2014. Tissue engineering studies on human alveolar subjects were included, and experiments that did not report quality or quantity of new regenerated bone were excluded. Twenty human experiments were included in our review. Regenerative techniques for alveolar cleft bone reconstruction were divided into cell therapy, growth factor application, and a combination of both cell therapy and growth factor. Using these three regenerative methods, a wide range of new bone formation percentages were reported. Due to insufficient evidence and controlled clinical trials, the treatment efficacy of tissue engineering in alveolar cleft bone defects could not be determined. Well-designed controlled studies are needed so that detailed outcomes can be properly compared.

Effects of the orientation of anti-BMP2 monoclonal antibody immobilized on scaffold in antibody-mediated osseous regeneration

Recently, we have shown that anti-BMP2 monoclonal antibodies (mAbs) can trap endogenous osteogenic BMP ligands, which can in turn mediate osteodifferentiation of progenitor cells. The effectiveness of this strategy requires the availability of the anti-BMP-2 monoclonal antibodies antigen-binding sites for anti-BMP-2 monoclonal antibodies to bind to the scaffold through a domain that will leave its antigen-binding region exposed and available for binding to an osteogenic ligand. We examined whether antibodies bound to a scaffold by passive adsorption versus through Protein G as a linker will exhibit differences in mediating bone formation. In vitro anti-BMP-2 monoclonal antibodies was immobilized on absorbable collagen sponge (ACS) with Protein G as a linker to bind the antibody through its Fc region and implanted into rat calvarial defects. The biomechanical strength of bone regenerated by absorbable collagen sponge/Protein G/anti-BMP-2 monoclonal antibodies immune complex was compared to ACS/anti-BMP-2 monoclonal antibodies or ACS/Protein G/isotype mAb control group. Results demonstrated higher binding of anti-BMP-2 monoclonal antibodies/BMPs to C2C12 cells, when the mAb was initially attached to recombinant Protein G or Protein G-coupled microbeads. After eight weeks, micro-CT and histomorphometric analyses revealed increased bone formation within defects implanted with absorbable collagen sponge/Protein G/anti-BMP-2 monoclonal antibodies compared with defects implanted with absorbable collagen sponge/anti-BMP-2 monoclonal antibodies (p < 0.05). Confocal laser scanning microscopy (CLSM) confirmed increased BMP-2, -4, and -7 detection in sites implanted with absorbable collagen sponge/Protein G/anti-BMP-2 monoclonal antibodies in vivo. Biomechanical analysis revealed the regenerated bone in sites with Protein G/anti-BMP-2 monoclonal antibodies had higher mechanical strength in comparison to anti-BMP-2 monoclonal antibodies. The negative control group, Protein G/isotype mAb, did not promote bone regeneration and exhibited significantly lower mechanical properties (p < 0.05). Altogether, our results demonstrated that application of Protein G as a linker to adsorb anti-BMP-2 monoclonal antibodies onto the scaffold was accompanied by increased in vitro binding of the anti-BMP-2 mAb/BMP immune complex to BMP-receptor positive cell, as well as increased volume and strength of de novo bone formation in vivo.

Role of bone morphogenetic protein-2 in osteogenic differentiation of mesenchymal stem cells

Bone mesenchymal stem cells (BMSCs) have been an area of interest in biomedical research and tissue engineering due to their diverse differentiation abilities. In osteogenesis, bone morphogenetic proteins (BMPs), particularly BMP-2, are important. However, the effect of BMP-2 on the osteogenetic capacity of BMSCs remains to be fully elucidated. In the present study, primary rat BMSCs were infected with a recombinant lentivirus carrying the BMP-2 gene (Lenti-BMP-2), and the effects of BMP-2 on the activity of alkaline phosphatase (ALP) on days 3, 7, 14 and 21, and on mineralization on day 21 were evaluated. In addition, the adhesive ability of BMP-2-overexpressed BMSCs was detected using an adhesion assay. Following forced expression of BMP-2 in the BMSCs, the levels of osteogenic genes, including osteopontin (OPN), osteocalcin (OC) and collagen type I (Col-I), were detected and the nuclear accumulation of Runt-related transcription factor (Runx)-2 and phosphorylated small mothers against decapentaplegic (p-Smad) 1/5/8 was also evaluated. The results demonstrated that the rat BMSCs had been isolated, cultured and passaged from Sprague-Dawley rat bone marrow successfully, and the third-generation BMSCs were identified using flow cytometry with CD29 staining. The osteogenetic phenotype of the BMSCs, expressing ALP and osteocalcin, was significantly induced by BMP-2, and the proliferation of the BMSCs was enhanced by BMP-2. Furthermore, the adhesive potential of the BMP-2-overexpressed BMSCs was increased, the expression levels of OPN, OCN and Col-Ie osteogenetic factors were upregulated and the nuclear accumulation of Runx-2 and p-Smads1/5/8 were increased significantly. These data suggested that BMP-2 may facilitate the osteogenetic differentiation of rat BMSCs and provide a favorable cell resource for tissue engineering.

Initial Experience With a New Intraoral Midface Distraction Device

Maxillary hypoplasia that necessitates surgical advancement affects approximately 25% of patients born with cleft lip and palate. Syndromic conditions such as Crouzon may also be accompanied by significant maxillary hypoplasia. Severe maxillary hypoplasia can result in airway obstruction, malocclusion, proptosis, and facial disfigurement. For optimal stability, severe hypoplasia is best addressed with maxillary distraction osteogenesis. Twenty-two patients (15 boys, 7 girls, ages 6–16 years, mean age 10 years) with severe midface hypoplasia underwent midface distraction with new internal maxillary distraction (IMD) device at our institution. Total distraction distances ranged from 15 to 30 mm. There were no major complications, and all of them had improvement in functional and aesthetic parameters. There were 2 minor complications and 2 patients failed to distract the full distance because of converging vectors. Early maxillary distraction in patients with severe midface hypoplasia is a useful technique to provide interval correction of severe maxillary hypoplasia before skeletal maturity and definitive orthognathic surgery is contemplated, and it is a good tool to improve occlusion, aesthetics, and self-perception in younger patients.

Parent, Dentist, and Orthodontist Satisfaction following Alveolar Cleft Repair Using Recombinant Human Bone Morphogenic Protein

Objective

Our aim was to evaluate dental/orthodontic outcomes for patients who underwent recombinant human bone morphogenic protein (rhBMP-2) alveolar cleft repair and to examine parental satisfaction following the procedure.

Design

Retrospective review.

Setting

Tertiary children's hospital.

Participants

Parents, dentists, and orthodontists completed satisfaction questionnaires.

Main Outcome Measures

Parent, dentist, and orthodontist satisfaction with the use of rhBMP-2 in alveolar cleft repair.

Results

Parent response rate was 71.4% (30/42). The dentist response rate was 60% (18/30). The orthodontist response rate was 53.3% (16/30). Parent and patient satisfaction was 93.3% and 83.3%, respectively. Of dentist respondents, 55.6% reported that the bone quality and alveolar ridge mucosal repair allowed for dental treatment. Of orthodontist respondents, 87.5% reported the graft enabled treatment, and 73.3% felt the graft prevented tooth root exposure and resorption.

Conclusions

Parents, dentists, and orthodontists are satisfied with outcomes when rhBMP-2 is used for alveolar cleft repair. The bone formed was reported as adequate to support dental and orthodontic treatment in most cases with few complications. Because of safety concerns over the use of this product in an off-label manner, further controlled studies are warranted.

Transforming growth factor beta 1 augments calvarial defect healing and promotes suture regeneration

BACKGROUND

Repair of complex cranial defects is hindered by a paucity of appropriate donor tissue. Bone morphogenetic protein 2 (BMP2) and transforming growth factor beta 1 (TGFβ1) have been shown separately to induce bone formation through physiologically distinct mechanisms and potentially improve surgical outcome for cranial defect repair by obviating the need for donor tissue. We hypothesize that a combination of BMP2 and TGFβ1 would improve calvarial defect healing by augmenting physiologic osteogenic mechanisms.

METHODS/RESULTS

Coronal suturectomies (3×15 mm) were performed in 10-day-old New Zealand White rabbits. DermaMatrix™ (3×15mm) patterned with four treatments (vehicle, 350 ng BMP2, 200 ng TGFβ1, or 350 ng BMP2+200 ng TGFβ1) was placed in suturectomy sites and rabbits were euthanized at 6 weeks of age. Two-dimensional (2D) defect healing, bone volume, and bone density were quantified by computed tomography. Regenerated bone was qualitatively assessed histologically. One-way analysis of variance revealed significant group main effects for all bone quantity measures. Analysis revealed significant differences in 2D defect healing, bone volume, and bone density between the control group and all treatment groups, but no significant differences were detected among the three growth factor treatment groups. Qualitatively, TGFβ1 treatment produced bone with morphology most similar to native bone. TGFβ1-regenerated bone contained a suture-like tissue, growing from the lateral edge of the defect margin toward the midline. Unique to the BMP2 treatment group, regenerated bone contained lacunae with chondrocytes, demonstrating the presence of endochondral ossification.

CONCLUSIONS/SIGNIFICANCE

Total healing in BMP2 and TGFβ1 treatment groups is not significantly different. The combination of BMP2+TGFβ1 did not significantly increase bone healing compared with treatment with BMP2 or TGFβ1 alone postoperatively at 4 weeks. We highlight the potential use of TGFβ1 to regenerate calvarial bone and cranial sutures. TGFβ1 therapy significantly augmented bony defect healing at an earlier time point when compared with control, regenerated bone along the native intramembranous ossification pathway, and (unlike BMP2 alone or in combination with TGFβ1) permitted normal suture reformation. We propose a novel method of craniofacial bone regeneration using low-dose, spatially controlled growth factor therapies to minimize potentially harmful effects while maximizing local bioavailability and regenerating native tissues.

Palatogenesis and cutaneous repair: A two-headed coin

BACKGROUND

The reparative mechanism that operates following post-natal cutaneous injury is a fundamental survival function that requires a well-orchestrated series of molecular and cellular events. At the end, the body will have closed the hole using processes like cellular proliferation, migration, differentiation and fusion.

RESULTS

These processes are similar to those occurring during embryogenesis and tissue morphogenesis. Palatogenesis, the formation of the palate from two independent palatal shelves growing towards each other and fusing, intuitively, shares many similarities with the closure of a cutaneous wound from the two migrating epithelial fronts.

CONCLUSIONS

In this review, we summarize the current information on cutaneous development, wound healing, palatogenesis and orofacial clefting and propose that orofacial clefting and wound healing are conserved processes that share common pathways and gene regulatory networks.

Nationwide practice patterns in the use of recombinant human bone morphogenetic protein-2 in pediatric spine surgery as a function of patient-, hospital-, and procedure-related factors

OBJECT

Current national patterns as a function of patient-, hospital-, and procedure-related factors, and complication rates in the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) as an adjunct to the practice of pediatric spine surgery have scarcely been investigated.

METHODS

The authors conducted a cross-sectional study using data from the Healthcare Cost and Utilization Project Kids' Inpatient Database. Univariate and multivariate logistic regression were used to calculate unadjusted and adjusted odds ratios and 95% confidence intervals, and p values < 0.05 were considered to be statistically significant.

RESULTS

The authors identified 9538 hospitalizations in pediatric patients 20 years old or younger who had undergone spinal fusion in the US in 2009; 1541 of these admissions were associated with rhBMP-2 use. By multivariate logistic regression, the following factors were associated with rhBMP-2 use: patient age 15-20 years; length of hospital stay (adjusted odds ratio [aOR] 1.01, p = 0.017); insurance status (private [aOR 1.49, p < 0.001] compared with Medicaid); hospital type (nonchildren's hospital); region (Midwest [aOR 2.49, p = 0.008] compared with Northeast); spinal refusion (aOR 2.20, p < 0.001); spinal fusion approach/segment (anterior lumbar [aOR 1.73, p < 0.001] and occipitocervical [aOR 1.86, p = 0.013] compared with posterior lumbar); short segment length (aOR 1.42, p = 0.016) and midlength (aOR 1.44, p = 0.005) compared with long; and preoperative diagnosis (Scheuermann kyphosis [aOR 1.56, p < 0.017] and spondylolisthesis [aOR 1.93, p < 0.001]).

CONCLUSIONS

Use of BMP in pediatric spine procedures now comprises more than 10% of pediatric spinal fusion. Patient-related (age, insurance type, diagnosis); hospital-related (children's hospital vs general hospital, region in the US); and procedure-related (redo fusion, anterior vs posterior approach, spinal levels, number of levels fused) factors are associated with the variation in BMP use in the US.

A glance at methods for cleft palate repair

Context:

Cleft palate is the second most common birth defect and is considered as a challenge for pediatric plastic surgeons. There is still a general lack of a standard protocol and patients often require multiple surgical interventions during their lifetime along with disappointing results.

Evidence Acquisition:

PubMed search was undertaken using search terms including 'cleft palate repair', 'palatal cleft closure', 'cleft palate + stem cells', 'cleft palate + plasma rich platelet', 'cleft palate + scaffold', 'palatal tissue engineering', and 'bone tissue engineering'. The found articles were included if they defined a therapeutic strategy and/or assessed a new technique.

Results:

We reported a summary of the key-points concerning cleft palate development, the genes involving this defect, current therapeutic strategies, recently novel aspects, and future advances in treatments for easy and fast understanding of the concepts, rather than a systematic review. In addition, the results were integrated with our recent experience.

Conclusions:

Tissue engineering may open a new window in cleft palate reconstruction. Stem cells and growth factors play key roles in this field.

Immobilization of murine anti-BMP-2 monoclonal antibody on various biomaterials for bone tissue engineering

Biomaterials are widely used as scaffolds for tissue engineering. We have developed a strategy for bone tissue engineering that entails application of immobilized anti-BMP-2 monoclonal antibodies (mAbs) to capture endogenous BMPs in vivo and promote antibody-mediated osseous regeneration (AMOR). The purpose of the current study was to compare the efficacy of immobilization of a specific murine anti-BMP-2 mAb on three different types of biomaterials and to evaluate their suitability as scaffolds for AMOR. Anti-BMP-2 mAb or isotype control mAb was immobilized on titanium (Ti) microbeads, alginate hydrogel, and ACS. The treated biomaterials were surgically implanted in rat critical-sized calvarial defects. After 8 weeks, de novo bone formation was assessed using micro-CT and histomorphometric analyses. Results showed de novo bone regeneration with all three scaffolds with immobilized anti-BMP-2 mAb, but not isotype control mAb. Ti microbeads showed the highest volume of bone regeneration, followed by ACS. Alginate showed the lowest volume of bone. Localization of BMP-2, -4, and -7 antigens was detected on all 3 scaffolds with immobilized anti-BMP-2 mAb implanted in calvarial defects. Altogether, these data suggested a potential mechanism for bone regeneration through entrapment of endogenous BMP-2, -4, and -7 proteins leading to bone formation using different types of scaffolds via AMOR.