FlexMetric bone marrow aspirator yields laboratory and clinically improved results from mesenchymal stem and progenitor cells without centrifugation.

Several devices used to harvest stem/progenitor cells from bone marrow are available to clinicians. This study compared three devices measuring stem cell yields and correlating those yields to bone regeneration. A flexible forward aspirating system Marrow Marxman (MM), a straight needle aspirating on withdrawal system Marrow Cellutions (MC), and a straight needle aspirating on withdrawal and centrifuging the aspirate (BMAC) were compared in a side-to-side patient comparison, as well as tissue engineered bone grafts. The FlexMetric system (MM) produced greater CFU-f values compared to the straight needle (MC) Δ = 1083/ml, p < 0.001 and 1225/ml, p < 0.001 than the BMAC system. This increased stem/progenitor cell yield also translated into a greater radiographic bone density at 6 months Δ = 88.3 Hu, p ≤ 0.001 versus MC and Δ = 116.7, p < 0.001 versus BMAC at 6 months and Δ = 72.2, p < 0.001 and Δ = 93.3, p < 0.001 at 9 months respectively. The increased stem/progenitor cell yield of the MM system clinically translated into greater bone regeneration as measured by bone volume p < 0.014 and p < 0.001 respectively, trabecular thickness p < 0.007 and p < 0.002 respectively, and trabecular separation p = 0.011 and p < 0.001. A flexible bone marrow aspirator produces higher yields of stem/progenitor cells. Higher yields of stem/progenitor cells translate into greater bone regeneration in tissue engineering. Flexmetric technology produces better bone regeneration due to a forward aspiration concept reducing dilution from peripheral blood and its ability to target lining cells along the inner cortex. Centrifugation systems are not required in tissue engineering procedures involving stem/progenitor cells due to nonviability or functional loss from g-forces.

Early Childhood (0 to 5 years) Presents the Greatest Risk for Facial Dog Bites.

PURPOSE: The purpose of the present study is to compare the characteristics of dog bite wounds to the face and that of the rest of the body among the pediatric population in the United States and to determine independent risk factors for dog bite wounds to the face. METHODS: A retrospective cohort study was conducted using the Kids' Inpatient Database. There were multiple, heterogenous predictor variables. The primary outcome variable was a facial dog bite. A multivariate logistic regression was employed to identify independent risk factors for the primary outcome variable. A P value less than .05 was the threshold for statistical significance. RESULTS: Our final sample consisted of 9,057 patients who suffered dog bite injuries, of which 2,913 (32.2%) occurred on the face. Relative to individuals aged 16-20 years, individuals aged 0-5 (odds ratio [OR] 5.7; confidence interval [CI] 4.0, 8.1), 6-10 (OR 3.8; CI 2.6, 5.5), and 11-15 years (OR 1.6; CI 1.1, 2.5) were all independently associated with increased odds of incurring a facial dog bite injury. Patients who were not admitted electively were 2.5 times (CI 1.4, 4.6) more likely to incur a facial dog bite injury relative to patients who were admitted electively. CONCLUSIONS: Young children (0-5 years) were at the greatest risk for facial dog bites relative to children aged 16-20 years. Dog bites that were admitted on emergency were more likely to occur on the face relative to those that were electively admitted to the hospital. To reduce the risk for facial dog bites and the host of chronic psychological ramifications that accompany them, established preventative strategies ought to be exercised.

Hyperbaric oxygen is still needed in the management and prevention of mandibular necrosis: a response to Mr. Richard Clarke.

Mr. Richard Clarke presents in this Journal his arguments against continued application of hyperbaric oxygen (HBO2) therapy to the pre-extraction neoadjuvant treatment or the treatment of frank mandibular ORN. In the same article he advocates a promising renewed interest in HBO2 as a radiosensitizer. Arguments against HBO2 prior to extractions are based on several papers which consistently include low-risk patients. The just-released HOPON trial reports a negative pre-extraction outcome for HBO2, but patients were enrolled with radiation doses as low as 50Gy. For advanced mandibular necrosis (Marx Stage III) requiring resection, fibular free flap reconstruction is advocated. A high complication rate with free flaps is acknowledged but the magnitude of these complications is not discussed. A cost savings for this procedure is suggested, but no mention is made of the typical cost of the procedure ($90,000) or the requirement of a typical one-week hospital stay, including an initial one or two days in the ICU. Nor is mention made of the very low rate of subsequent dental rehabilitation. The success reported by Delainian, et al. employing pentoxifylline, Vitamin E and sometimes a bisphosphonate is equated to the four decades of HBO2 success with the Marx protocol for Stage I and II ORN. In the phase II trial by Delainian (not randomized) six of her 54 patients died secondary to sepsis, and she graded patients as complete responders if 5mm or less bone was exposed. Even at entry patients had an average of only 1.7 cm exposed bone and treatment was prolonged (16 + or -9 months). Any cost comparison studies will have to account for the indirect expenses of this prolonged treatment including lost productivity.

Reconstruction of a Post-Traumatic Maxillary Ridge Using a Radial Forearm Free Flap and Immediate Tissue Engineering (Bone Morphogenetic Protein, Bone Marrow Aspirate Concentrate, and Cortical-Cancellous Bone): Case Report.

The purpose of this article is to describe reconstruction of the maxillary alveolar ridge by use of a microvascular free flap combined with an immediate tissue-engineered bone graft. This novel surgical technique involved the use of a radial forearm free flap and immediate allogeneic avascular bone graft augmented with bone morphogenetic protein and bone marrow aspirate concentrate. A poly-d,l-lactic acid mesh was used as a containment unit for the bone graft. The patient was successfully treated with a viable radial forearm free flap for soft tissue and regeneration of bone with adequate height and width, which allowed the placement of 3 dental implants with excellent arch coordination. We believe this is the first published case describing such a technique to reconstruct the maxillary alveolus.

Regeneration of a Tooth in a Tissue-Engineered Mandible After Resection of a Central Giant Cell Tumor. Demonstrating Evidence of Functional Matrix Theory and Ectodermal Origin of Teeth in a Human Model-A Case Report.

Central giant cell tumors (CGCTs) are uncommon lesions occurring in the jaw. They are benign but locally destructive osteolytic lesions. They usually occur in pediatric patients 5 to 15 years of age. Multiple noninvasive modalities of treatment (intralesional steroids, interferon, calcitonin, and denosumab) have been described for those lesions, but for those that are refractory to treatment, enucleation and curettage or resection is a curative surgery. This case report describes a pediatric patient who was diagnosed with an aggressive CGCT of the left mandible encompassing the right angle to the condyle. The lesion became refractory to noninvasive treatments and immediate resection and reconstruction was performed using principles of tissue engineering. After 5 years of close observation, the patient showed normal morphology and growth of his mandible, but surprisingly developed a left mandibular third molar (tooth 17) in the site of the mandibular resection and reconstruction. This is the first case report in the literature to show the spontaneous development of teeth in a human reconstructed mandible, contributing evidence toward the functional matrix theory of mandibular growth and ectodermal origin of teeth.

A technique for the treatment of oral-antral fistulas resulting from medication-related osteonecrosis of the maxilla: the combined buccal fat pad flap and radical sinusotomy.

OBJECTIVE: Bisphosphonates and monoclonal antibodies directed at osteoclastic function are frequently used to treat postmenopausal and corticosteroid-induced osteoporosis. They are also used in the treatment of certain metastatic malignancies. However, osteonecrosis of the jaw has been reported after intravenous, subcutaneous, or oral use of these agents. More than 12 million Americans and another 20 million worldwide are thought to be taking a bisphosphonate. Exposed bone with oral-antral fistulas has been known to occur increasingly as a specific presentation of what is now termed medication-related osteonecrosis of the jaws (MRONJ) with a specific International Classification of Diseases, 10th revision (ICD-10) code. Oral-antral communications caused by bisphosphonate concomitant with secondary sinusitis represent a unique treatment challenge for the oral and maxillofacial surgeon. The purpose of this article is to demonstrate a simple but effective technique to treat oral-antral communications caused by MRONJ. STUDY DESIGN: With the review and approval of the University of Miami Internal Review Board, we identified 23 patients who had undergone this surgical procedure. RESULTS: We report a 100% resolution of osteonecrosis of the jaw (ONJ) and sinusitis with repneumatization. CONCLUSIONS: The buccal fat pad and radical sinustomy can be used as an effective and predictable technique for the resolution of oral-antral fistulas caused by MRONJ.

Recurrent Malignancy in Osteoradionecrosis Specimen.

PURPOSE: Osteoradionecrosis (ORN) is a well-known complication of head and neck radiation therapy. Statistically, the mandible is the most commonly affected site. The incidental finding of malignancy in the resection specimen has been documented but is somewhat rare. The aim of this review is to investigate the presence of recurrent carcinoma and sarcoma or new primary malignancies in resection specimens previously diagnosed and treated as ORN. PATIENTS AND METHODS: This study is a retrospective case series. We conducted a chart review of all cases managed at the University of Miami Miller School of Medicine/Jackson Memorial Hospital. The inclusion criteria included a history of head and neck carcinoma treated with radiation of at least 6,000 cGy; clinical diagnosis of ORN; and surgical intervention with osseous resection for treatment of ORN. The study endpoint measured included microscopic evidence of malignancy in the resected ORN specimen. Additional data collected included gender, age, and type of primary pathology. RESULTS: A total of 564 patients met the inclusion criteria. Of these patients, 14 had microscopic evidence of cancer in the specimen (2.48%) and 5 had a proven second primary malignancy in the foregut (1 in the lung, 0.18%, and 4 in the oropharynx, 0.70%). In 1 of the 14 patients, a high-grade sarcoma was diagnosed and the patient died within 1 year of diagnosis. In the treatment of our ORN patient population, a total of 19 malignancies were found collectively (3.37%). Of the 564 patients, 352 were men and 212 were women. The median age was 46 years (range, 33 to 97 years). Head and neck squamous cell carcinoma represented 531 cases in our sample, followed by 28 cases of salivary gland carcinoma and only 5 cases of sarcoma. CONCLUSIONS: Although the finding of malignancy in ORN patients is relatively rare (3.37% in this study), oral and maxillofacial surgeons should be cognizant of its potential presence. The treatment of malignant disease is different than that of ORN, and a multidisciplinary treatment approach is recommended if a malignancy is diagnosed in an ORN patient.

Translational research: The CD34+ cell is crucial for large-volume bone regeneration from the milieu of bone marrow progenitor cells in craniomandibular reconstruction.

PURPOSE: This study investigated the role of the bone marrow-derived CD34+ cell in a milieu of osteoprogenitor cells, bone marrow plasma cell adhesion molecules, recombinant human bone morphogenetic protein (rhBMP), and a matrix of crushed cancellous allogeneic bone in the clinical regeneration of functionally useful bone in craniomandibular reconstructions. The history and current concepts of bone marrow hematopoietic stem cells and mesenchymal stem cells are reviewed as they relate to bone regeneration in large continuity defects of the mandible. MATERIALS AND METHODS: Patients with 6- to 8-cm continuity defects of the mandible with retained proximal and distal segments were randomized into two groups. Group A received an in situ tissue-engineered graft containing 54 ± 38 CD34+ cells/mL along with 54 ± 38 CD44+, CD90+, and CD105+ cells/mL together with rhBMP-2 in an absorbable collagen sponge (1 mg/cm of defect) and crushed cancellous allogeneic bone. Group B received the same graft, except the CD34+ cell concentration was 1,012 ± 752 cells/mL. The results were analyzed clinically, radiographic bone density was measured in Hounsfield units (HU), and specimens were analyzed histomorphometrically. RESULTS: Forty patients participated (22 men and 12 women; mean age, 57 years). Eight of 20 group A patients (40%) achieved the primary endpoint of mature bone regeneration, whereas all 20 group B patients (100%) achieved the primary endpoint. CD34+ cell counts above 200/mL were associated with achievement of the primary endpoint. Bone density was lower in group A (424 ± 115 HU) than in group B (731 ± 98 HU). Group A bone showed a mean trabecular bone area of 36% ± 10%, versus 67% ± 13% for group B. CONCLUSIONS: The CD34+ cell functions as a central signaling cell to mesenchymal stem cells and osteoprogenitor cells in bone regeneration. The mechanism of bone marrow-supported grafts requires a complete milieu to regenerate large quantities of functionally useful bone. CD34+ cell counts in a concentration of at least 200/mL in composite grafts are directly correlated to clinically successful bone regeneration.

A decade of bisphosphonate bone complications: what it has taught us about bone physiology.

While the AIDS epidemic of the 1980s taught the medical and dental professions much about immune cells and the immune system's cellular relationships, the bisphosphonate-induced osteonecrosis epidemic of the past decade has taught these same professions much about bone turnover, bone cell cross talk, the response and functional relationship of bone cells to loading, and drug effects on cellular dynamic relationships. The present article explores the literature as well as both evidence- and experience-based data to discuss known bone pathologies and physiologic mechanisms as well as uncover new findings: (1) bone remodeling is the mechanism by which bone adapts to loading stresses, termed either bone modeling or Wolff's law, and it is also the mechanism for bone renewal; (2) osteoclastic bone resorption triggers bone renewal at a rate of about 0.7%/day by its release of growth factors; (3) bisphosphonates prevent the renewal of old and injured bone, thus making it brittle and more likely to fracture over time; (4) bisphosphonates have a half-life in bone of 11 years because of their irreversible binding to bone via their central carbon atom; (5) when administered intravenously, bisphosphonate loads bone and accumulates in bone 142.8 times faster than when administered orally; (6) osteoclastic resorption of bisphosphonate-loaded bone results in osteoclast death in which the cell bursts, releasing the bisphosphonate molecules to reenter the local bone or bone marrow in a re-dosing effect; (7) endosteal osteoblasts are dependent on the osteoclastic resorption/growth factor release/new bone formation mechanism of bone renewal, whereas periosteal osteoblasts are not; and (8) it is likely that endosteal osteoblasts and periosteal osteoblasts have different cell membrane receptors and arise from separate embryologic niches.

The deception and fallacies of sponsored randomized prospective double-blinded clinical trials: the bisphosphonate research example.

The randomized prospective double-blinded clinical trial (RCT) is accepted as Level I evidence and is highly regarded. However, RCTs that gained FDA approval of drugs such as Vioxx, Fen-Phen, and oral and intravenous bisphosphonates have proven to generate misleading results and have not adequately identified serious adverse reactions. The development, research, and clinical marketing of the oral and intravenous bisphosphonates can serve as a representative example for the deteriorated value of many of today's RCTs. The expected high value of RCTs is jeopardized by: (1) sponsorship that incorporates bias; (2) randomization that can select out an expected improved result or eliminate higher-risk individuals; (3) experimental design that can avoid recognition of serious adverse reactions; (4) blinding that can easily become unblinded by the color, shape, odor, or administration requirements of a drug; (5) definitions that can define an observation as something other than what it actually represents, or fail to define it as an adverse reaction; (6) labeling of retrospective data as a prospective trial by using adjudicators prospectively to look at retrospective data; (7) change of the length of study to avoid the longer-term adverse reaction from accumulation of drug or treatment effects; (8) ghost writing, as when drug company physicians or a hired corporation either edit or write the entire protocol and/or manuscript for publication. Such corruption of the well-intended properly conducted RCT should be viewed with a sense of outrage by practitioners and requires a restructuring of the levels of evidence accepted today.

rhBMP-2/ACS grafts versus autogenous cancellous marrow grafts in large vertical defects of the maxilla: an unsponsored randomized open-label clinical trial.

PURPOSE: This study compared the histologic parameters and outcomes of two types of grafts in large vertical maxillary defects: a composite graft of recombinant human bone morphogenetic protein-2/acellular collagen sponge (rhBMP-2/ACS), crushed cancellous freeze-dried allogeneic bone (CCFDAB), and platelet-rich plasma (PRP); and size-matched 100% autogenous grafts. MATERIALS AND METHODS: Twenty patients each were treated with a composite graft, which contained 1.05 mg rhBMP-2/ACS per two-tooth segment together with CCFDAB and PRP, or a 100% autogenous graft prior to implant placement. Grafting material was contained within a titanium mesh crib. RESULTS: Two grafts in each group were lost as a result of early mesh exposure and infection. Three grafts in each group developed a late exposure of the mesh that did not affect bone regeneration. The remaining 18 autogenous grafts all regenerated sufficient bone for implant restoration (100%), and 17 of 18 (97.4%) of the composite grafts regenerated sufficient bone for implant restoration. The autogenous grafts included 54% ± 10% of new viable bone but also included residual nonviable graft particles. The composite grafts contained 59% ± 12% viable new bone and no remaining nonviable bone particles. The composite grafting technique resulted in less blood loss and shorter surgical time but greater and longer-lasting edema. The costs of both grafts were nearly equal. CONCLUSION: A composite graft of rhBMP-2/ACS-CCFDAB-PRP regenerates bone in large vertical ridge augmentations as predictably as 100% autogenous graft with less morbidity, equal cost, and more viable new bone formation without residual nonviable bone particles, but with more edema. This composite graft represents an in situ tissue engineering concept that is able to achieve results equivalent to autogenous grafts in large vertical ridge augmentations without donor bone harvesting.

A qualitative and quantitative analysis of autologous human multipotent adult stem cells derived from three anatomic areas by marrow aspiration: tibia, anterior ilium, and posterior ilium.

PURPOSE: The purpose of this article was to compare the yields of stromal multipotent stem cells (CD34+ and CD105+) and hematopoetic multipotent stem cells (CD44+) obtained from different areas via bone marrow aspiration (BMA). MATERIALS AND METHODS: Sixty 60-mL bone marrow aspirates were taken from the tibial plateau, the anterior ilium, and the posterior ilium using a single point-of-care BMA technique and a single BMA concentration (BMAC) device. A 1-mL portion of each sample was used to determine CD stem cell concentrations and the nucleated cell count. The remaining BMA was centrifuged to separate the more mature red blood cell precursors from the stem cells and then concentrate the latter into a BMAC. The BMAC yield of 10 mL was analyzed with flow cytometry and nucleated cell counts to derive a concentration factor for the BMAC. RESULTS: The yield of total nucleated cells was equal between the anterior and posterior ilium and more than twice that obtained from the tibial plateau. The CD44+ and CD105+ cell yields were also nearly equal between the anterior and posterior ilium but more than twice that of the tibial plateau; however, the ratios between the three different stem cell types in BMAC obtained from the different areas suggest varying potentials for tissue development. CONCLUSIONS: The ilium is the preferred donor site for obtaining autologous stem cells at the point of care. The tibial plateau yielded only half as much bone marrow multipotent/progenitor stem cells as did the anterior and posterior ilium. The composition of the BMAC from each site suggests that the potential for differentiation into various cell types changes depending on the source of bone marrow, but that BMAC represents 6.5 ± 1.0 concentration factor from BMA.

Biointegration of the osteo-odonto lamina in the modified osteo-odonto keratoprosthesis: engineering of tissue to restore lost vision.

The modified osteo-odonto keratoprosthesis (MOOKP) is a biologic keratoprosthesis that is used to treat a severely scarred cornea. The procedure involves multiple stages, including the transplantation of buccal mucosa to the damaged ocular surface and the implantation of an osteo-odonto lamina with a mounted polymethylmethacrylate lens. Among the keratoprostheses currently available, the MOOKP has proven to be the most effective based on the number of patients who have undergone the procedure and the duration of documented follow-up. Upon successful biointegration of the osteo-odonto lamina, the keratoprosthesis is able to resist resorption, provide stability, and prevent bacterial invasion and epithelial ingrowth. The effectiveness of the MOOKP is dependent on the anatomic and physiologic characteristics of the dental tissues and periodontal ligament.

Dental implants and the use of rhBMP-2.

Tissue engineering is an emerging field of medicine and dentistry that combines the body's natural biologic response to tissue injury with engineering principles. The goal is to replicate or reconstruct the natural form and function of missing tissues and organs. Tissue-engineered bone with native qualities will be necessary for implantation or migration of engineered teeth in the future, and is currently required for the osseointegration of dental implants. This article addresses the role of bone morphogenetic proteins (BMP) in native bone healing for implant osseointegration and the application of BMP for de novo bone regeneration.