Maxillofacial Defects and the Use of Growth Factors

Efficacy of Recombinant Human Bone Morphogenetic Protein-2 in Alveolar Cleft Treatment for Children: Systematic Review and Meta-Analysis

BACKGROUND

Alveolar bone reconstruction with recombinant protein has several advantages, including less surgical timing, and reduced infection. This systematic review aims to assess the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2) as a treatment modality for children with cleft lip and palate compared to the conventional iliac crest bone grafting approach.

METHODS

For current systematic review and meta-analysis, five electronic databases, namely, MEDLINE/PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials.gov, Web of Science, and ScienceDirect, were searched. The primary outcome measured in this review was bone volume and height after alveolar bone reconstruction surgery. The Risk of Bias Tool 2 assessed the risk of bias for randomized control trials and the Risk of Bias tool for non-randomized trials of interventions for non-randomized studies. By evaluating pooled meta-analysis, the mean difference was calculated. GRADE uncertainty of evidence was performed to assess the certainty of the results.

RESULTS

Of 230 identified studies, 6 randomized and 2 non-randomized studies were included in the current review. The average bone volume was higher among the rhBMP-2 group at 61.11% ± 24.6% than the iliac crest group at 59.12% ± 18.59%. The calculated mean bone height was higher in the iliac crest group at 78.65% ± 14.38% than in the rhBMP-2 group at 67.5% ± 5.45%. The risk of bias reported in the studies was low to moderate. The result of the meta-analysis supported using rhBMP-2 in alveolar bone reconstruction; however, no significant association was found (mean difference: -1.24; confidence interval: -4.14 to 1.67).

CONCLUSIONS

The calculated meta-analysis reported no significant difference, and the quality of evidence measured was also moderate. Hence, more clinical trials are required to support using rhBMP-2 as an alternative to traditional techniques for treating cleft lip and palate.

Novel Approaches for the Treatment of Maxillofacial Defects

Maxillofacial defects, located in a region characterized by a complex interplay of soft and hard tissues, along with a sophisticated capillary and neural network, have long posed significant challenges in both clinical practice and research [...].

Tissue Engineering Supporting Regenerative Strategies to Enhance Clinical Orthodontics and Dentofacial Orthopaedics: A Scoping, Perspective Review

The personalized regenerative therapeutic strategies applicable in the structural and functional repair of maxillofacial/dental defects are expected to extend beyond the limits of what is currently possible in the management of dentofacial anomalies and treating malocclusions. The application of undifferentiated stem cells (SCs), including signaling molecule control and individualized tissue engineering based on targeted therapies, has been proposed to overcome therapeutic limitations and complications associated with treatments for craniofacial defects, including severe orthodontic discrepancies. This scoping, prospective review discusses comprehensively the current knowledge and prospects for improving clinical outcomes by the application of novel cell-required and cell-free regenerative strategies in biomedicine. The existing evidence, although scant, suggests that patients receiving an orthodontic treatment could benefit from precise tissue augmentation, allowing enhancement of tooth movement generated by orthognathic forces; faster, more predictable alignment of dental arches; optimal management of periodontal complications; and prevention of external root resorption. Ultimately, enriching orofacial tissues and “customizing” the repair of congenital/acquired defects in the craniofacial region can be vastly enhanced to provide a positive therapeutic outcome and improve patients’ quality of life.

Senescence-associated secretory phenotypes in rat-derived dedifferentiated fat cells with replicative senescence

Senescence-associated secretory phenotype (SASPs) secreted from senescent cells often cause the deleterious damages to the surrounding tissues. Although dedifferentiated fat (DFAT) cells prepared are considered a promising cell source for regenerative therapies, SASPs from DFAT cells undergoing long-term cell culture, which latently induce replicative senescence, have barely been explored. The present study was designed to investigate senescent behaviors in rat-derived DFAT cells at high passage numbers and to analyze the possible types of SASPs. Our data show that DFAT cells undergo senescence during replicative passaging, as determined by multiple senescent hallmarks including morphological changes in cell shape and nucleus. Moreover, RT² PCR array analysis indicated that senescent DFAT cells expressed higher levels of 16 inflammatory cytokines (Ccl11, Ccl12, Ccl21, Ccl5, Csf2, Cxcl1, Cxcl12, Ifna2, IL11, IL12a, IL13, IL1a, IL1rn, IL6, Mif, and Tnf) associated with SASPs than non-senescent cells. This study implicates that rat DFAT cells undergo cellular senescence after long-term cell culture; cautious consideration should be paid to treat SASP secretion when senescent DFAT cells are used in regenerative medicine.

Electrospun polylactic acid scaffolds with strontium- and cobalt-doped bioglass for potential use in bone tissue engineering applications

The development of nanoscale biomaterials associated with polymers has been growing over the years, due to their important structural characteristics for applications in biological systems. The present study aimed to produce and test polymeric scaffolds composed of polylactic acid (PLA) fibers associated with a 58S bioglass doped with therapeutic ions for use in tissue engineering. Three 58S Bioglass was obtained by the sol-gel route, pure and doped with 5% strontium and cobalt ions. Solutions of 7% PLA was used as control and added the three different bioglass, 4% of 58S bioglass (PLA-BG), 4% bioglass-doped strontium (PLA-BGSr) and 4% bioglass-doped cobalt (PLA-BGCo). Scaffolds were produced through electrospinning process, and was characterized chemical and morphologically. The in vitro tests were performed using mesenchymal cells cultures from femurs of nine rats, grown in osteogenic supplemented total culture medium. After osteoblastic differentiation induction cell viability, alkaline phosphatase activity, total protein content quantification, and visualization of mineralization nodule tests were performed. Analysis of normal distribution used the Shapiro-Wilk test (nanofibers diameter and biological assay). Data were compared using the Kruskal-Wallis nonparametric test (p = 0.05). The bioglasses produced proved to be free of nitrate, chlorinated and nano-sized, with effective incorporation of therapeutic ions in their structure. All materials showed cell viability (>70%), total protein production, and alkaline phosphatase activity. It was possible to develop polylactic acid scaffolds associated with 58S bioglass doped with therapeutic ions without cytotoxicity. Scaffolds characteristics appear to sustain its application in bone tissue engineering.

Mesenchymal Stem Cells Based Treatment in Dental Medicine: A Narrative Review

Application of mesenchymal stem cells (MSC) in regenerative therapeutic procedures is becoming an increasingly important topic in medicine. Since the first isolation of dental tissue-derived MSC, there has been an intense investigation on the characteristics and potentials of these cells in regenerative dentistry. Their multidifferentiation potential, self-renewal capacity, and easy accessibility give them a key role in stem cell-based therapy. So far, several different dental stem cell types have been discovered and their potential usage is found in most of the major dental medicine branches. These cells are also researched in multiple fields of medicine for the treatment of degenerative and inflammatory diseases. In this review, we summarized dental MSC sources and analyzed their treatment modalities with particular emphasis on temporomandibular joint osteoarthritis (TMJ OA).

Distraction Osteogenesis and Customized Temporomandibular Joint Prosthesis in the Reconstruction of a Large Mandibular Defect - A Case Report

The Rationale:

Mandibular resections involve esthetic and functional impairment and impose a challenge during the reconstruction. This case report is a successful reconstruction with distraction osteogenesis (DO) and customized temporomandibular joint (TMJ) prosthesis.

Patient Concerns:

A 51-year-old male patient presented with a complaint of facial asymmetry, mastication, and speech difficulties.

Diagnosis:

As the patient had undergone a hemimandibulectomy procedure 20 years ago, clinical examination showed facial asymmetry. Radiographic examination exhibited the defect and a radiopaque image representing Kirschner's wire.

Treatment:

DO by bone transport was performed, followed by dental implant and TMJ prosthesis placement.

Outcomes:

DO is a viable treatment option in resections, even when the defect was generated by an ancient injury. The follow-up is around 7 years after the osteogenic distraction, with no complaints and functional capacity.

Take-away Lessons:

The major challenge in mandibular reconstructions through DO is to reproduce the curve of the arch.

Degradable RGD-Functionalized 3D-Printed Scaffold Promotes Osteogenesis

To establish an ideal microenvironment for regenerating maxillofacial defects, recent research interests have concentrated on developing scaffolds with intricate configurations and manipulating the stiffness of extracellular matrix toward osteogenesis. Herein, we propose to infuse a degradable RGD-functionalized alginate matrix (RAM) with osteoid-like stiffness, as an artificial extracellular matrix, to a rigid 3D-printed hydroxyapatite scaffold for maxillofacial regeneration. The 3D-printed hydroxyapatite scaffold was produced by microextrusion technology and showed good dimensional stability with consistent microporous detail. RAM was crosslinked by calcium sulfate to manipulate the stiffness, and its degradation was accelerated by partial oxidation using sodium periodate. The results revealed that viability of bone marrow stem cells was significantly improved on the RAM and was promoted on the oxidized RAM. In addition, the migration and osteogenic differentiation of bone marrow stem cells were promoted on the RAM with osteoid-like stiffness, specifically on the oxidized RAM. The in vivo evidence revealed that nonoxidized RAM with osteoid-like stiffness upregulated osteogenic genes but prevented ingrowth of newly formed bone, leading to limited regeneration. Oxidized RAM with osteoid-like stiffness facilitated collagen synthesis, angiogenesis, and osteogenesis and induced robust bone formation, thereby significantly promoting maxillofacial regeneration. Overall, this study supported that in the stabilized microenvironment, oxidized RAM with osteoid-like stiffness offered requisite mechanical cues for osteogenesis and an appropriate degradation profile to facilitate bone formation. Combining the 3D-printed hydroxyapatite scaffold and oxidized RAM with osteoid-like stiffness may be an advantageous approach for maxillofacial regeneration.

In situ printing of scaffolds for reconstruction of bone defects

Bone defects are commonly caused by traumatic injuries and tumor removal and critically sized defects overwhelm the regenerative capacity of the native tissue. Reparative strategies such as auto, xeno, and allografts have proven to be insufficient to reconstruct and regenerate these defects. For the first time, we introduce the use of handheld melt spun three dimensional printers that can deposit materials directly within the defect site to properly fill the cavity and form free-standing scaffolds. Engineered composite filaments were generated from poly(caprolactone) (PCL) doped with zinc oxide nanoparticles and hydroxyapatite microparticles. The use of PCL-based materials allowed low-temperature printing to avoid overheating of the surrounding tissues. The in situ printed scaffolds showed moderate adhesion to wet bone tissue, which can prevent scaffold dislocation. The printed scaffolds showed to be osteoconductive and supported the osteodifferentiation of mesenchymal stem cells. Biocompatibility of the scaffolds upon in vivo printing subcutaneously in mice showed promising results. STATEMENT OF SIGNIFICANCE.

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.

Usage of stem cells in oral and maxillofacial region

Malformations of the maxillofacial region has disturbing psychosocial effects and causes enormous socioeconomic concerns. The management of maxillofacial defects caused by congenital anomalies, trauma, osteoporotic fractures, periodontitis, or cancer treatment is challenging for oral and maxillofacial surgeons. Numerous approaches have been recommended for the managing of these deficiencies. The traditional treatment for maxillofacial defects or their repair is an intricate process by autologous bone grafts from the scapula, ribs, fibula, or iliac crest origins. Regenerative medicine is well thought-out as a perfect substitute approach for autologous bone grafts to renovate bone deficiencies. The use of stem cells has improved results and offered a technique to reconstruct craniofacial bone defects. The field of tissue engineering for the regeneration of maxillofacial needs integration of biochemical and biomaterial engineering aspects with cell transplantation to generate better-quality biomimetic scaffolds, prevascularize three-dimensional (3D) tissue structures, and engineer the composite interface of diverse facial tissues. In this review, we have discussed the application of different adult stem cells to repair oral and maxillofacial defects in animal models and clinical trials.

Evaluating the efficacy of recombinant human bone morphogenic protein-2 in the treatment of alveolar clefts with autologous bone grafting using computer-aided engineering techniques

Recent studies have indicated the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) to be a viable adjunctive to alveolar cleft reconstruction owing to its osteoinductive capacity. This study aimed to evaluate the efficacy of rhBMP-2 in the treatment of alveolar cleft with autologous bone grafts by precise volumetric analysis. Twenty-six patients (aged 8-14) with unilateral alveolar clefts were enrolled in this comparative study. Patients were divided into two groups: the iliac crest bone graft (ICBG) was placed at the side of the cleft in the control group (ICBG group), and rhBMP-2 was mixed with the ICBG in the rhBMP-2 group (BMP group). Helical computed tomographic images were obtained preoperatively and 12 months postoperatively. The datasets were reconstructed as three-dimensional (3D) images using Mimics software and processed using Geomagic Wrap. The newly formed bone of the alveolar cleft was segmented by identifying the differences between preoperative and postoperative 3D images. In the ICBG group, the volume of newly formed bone ranged from 0.25 to 0.88 cm³, and the mean (SD) bone formation percentage was 42.01% (15.57%). In the BMP group, the volume of newly formed bone ranged from 0.34 to 1.09 cm³, and the bone formation mean (SD) percentage was 55.79% (11.84%). There was a statistically significant difference between the two groups in terms of the postoperative percentage of bone formation (p = 0.022). Thus, rhBMP-2 combined with an autologous bone graft is a promising technique to improve the results of secondary alveolar bone grafting.

Advances in regenerative medicine for otolaryngology/head and neck surgery

Head and neck structures govern the vital functions of breathing and swallowing. Additionally, these structures facilitate our sense of self through vocal communication, hearing, facial animation, and physical appearance. Loss of these functions can lead to loss of life or greatly affect quality of life. Regenerative medicine is a rapidly developing field that aims to repair or replace damaged cells, tissues, and organs. Although the field is largely in its nascence, regenerative medicine holds promise for improving on conventional treatments for head and neck disorders or providing therapies where no current standard exists. This review presents milestones in the research of regenerative medicine in head and neck surgery.

Risk factors in bone augmentation procedures

Bone augmentation is an extremely common procedure in implant dentistry today because of significant advancements with reactive biomaterials, a better understanding of the mechanism of action that is found with growth factors contained in platelets, and improvements in surgical techniques. The expectation is for the surgeon to place the dental implant in the position that best serves the requirements of the prosthetic restorations. With the increasing demands that patients have for ideal prosthetic results, surgeons are expected to predictably augment both hard and soft tissues to provide the anticipated esthetic and functional outcomes. Bone grafting can be performed before, during, and after the implant placement; however, these augmentation procedures come with increased cost, the risk of complications such as infection or failure, and lengthening of the total treatment time. In addition, a plethora of grafting materials are available commercially, where they are often inadequately studied, or there is minimal information regarding their predictability or long-term success, or ability to support dental implants. It is clear that although the surgical field has seen major progress since early implant surgical techniques in the 1980s, major challenges still exist with hard tissue augmentation procedures. This review will discuss these challenges that are increased and often specific to bone graft healing, and which are becoming more common as implant site development often requires bone augmentation to improve volume or contour deficiencies. The risk factors that patients may present with that will affect outcomes with bone augmentation procedures are identified, and recommendations for the prevention of complications or managing complications once they have occurred are provided.

Experimental study of the synergistic effect and network regulation mechanisms of an applied combination of BMP-2, VEGF, and TGF-β1 on osteogenic differentiation

The study aimed to explore the osteogenic effect induced by the combined use of bone morphogenetic protein-2 (BMP-2), vascular endothelial growth factor (VEGF), and transforming growth factor-β1 (TGF-β1), attain the best combination for osteogenic quality and efficiency, and explore the network regulation mechanisms of induced osteogenesis. MC3T3-E1 cells were cultured in vitro, and BMP-2, VEGF, and TGF β1 were added to osteogenic induction mediums in different combinations to conduct experiments. At 7 and 14 days, the alkaline phosphatase (ALP) and Alizarin Red S (ARS) staining of the applied BMP-2 and VEGF combination were deeper and the quantitative analysis were higher than those of the other groups. After optimizing the time-effect relationship of the combined application, with BMP-2, VEGF, and TGF-β1 adding in the early stage and BMP-2 and VEGF adding in the late, the ALP and ARS staining of these groups were deeper and the quantitative analyses were meaningfully higher than the BMP-2 and VEGF combination group at 7 and 14 days. The expression of the RUNX2 gene and the Smad1 signaling pathway in the optimized combination group was also significantly higher. The results demonstrate that the combination of BMP-2, VEGF, and TGF-β1 applied according to the time-effect relationship can significantly promote osteogenic differentiation mainly through the classical BMP-receptor-Smad signal pathway.

Tissue Engineering: What is New?

Soft and hard tissue engineering has expanded the frontiers of oral/maxillofacial augmentation. Soft tissue grafting enhancements include improving flap prevascularization and using stem cells and other cells to create not only the graft, but also the vascularization and soft tissue scaffolding for the graft. Hard tissue grafts have been enhanced by osteoinductive factors, such as bone morphogenic proteins, that have allowed the elimination of harvesting autogenous bone and thus decrease the need for other surgical sites. Advancements in bone graft scaffolds have developed via seeding with stem cells and improvement of the silica/calcium/phosphate composite to improve graft characteristics and healing.

Efficacy of rhBMP-2 in Cleft Lip and Palate Defects: Systematic Review and Meta-analysis

The aim of this study was to analyze the efficacy of using rhBMP-2 (recombinant human morphogenetic protein-2) in the treatment of patients with cleft lip and palate defects (CLPD). Seven databases were screened: PubMed (Medline), Lilacs, Ibecs, Web of Science, BBO, Scopus, and The Cochrane Library. Clinical trials that evaluated the use of bioactive treatment with rhBMP-2 in the treatment of patients with CLPD were included. Statistical analyses were performed by comparing the standardized mean difference of bone formation volume and bone filling percentage (p = 0.05). Ten studies compared the use of rhBMP-2 and iliac crest bone graft (ICBG). The global analysis for bone formation volume and bone filling percentage showed that bioactive materials were similar to ICBG with a standardized mean difference of respectively 0.07 (95% CI - 0.41 to 0.56) and 0.24 (95% CI - 0.32 to 0.80). The available literature suggested that use of rhBMP-2 presented similar bone formation results to those of ICBG in secondary alveolar bone grafting for patients with CLPD.

Impact of incubation method on the release of growth factors in non-Ca2+-activated PRP, Ca2+-activated PRP, PRF and A-PRF

The aim of this study was to investigate the influence of different incubation methods on the growth factor content of lysates of platelet-rich fibrin (PRF), advanced-platelet-rich fibrin (A-PRF) and platelet-rich plasma (PRP) products. A comparison of related studies suggests that the method of sample preparation has a significant influence on growth factor content. There are few reports on the comparison of non-Ca²⁺-activated PRP, Ca²⁺-activated PRP, A-PRF, and PRF, along with a lack of information on the release of PDGF-BB, TGF-β1, and VEGF among the different incubation methods. The lysate preparation was made of non-Ca²⁺-activated PRP, Ca²⁺-activated PRP, PRF, and A-PRF, using a room-temperature, 37 °C, or freeze-thaw-freeze incubation method. Afterwards the VEGF, PDGF-BB, and TGF-β1 content was investigated by running ELISA tests. Growth factor levels were significantly increased in the non-Ca²⁺-activated PRP with freeze-thaw-freeze incubation, and in the PRF preparation there was a significant disadvantage to using room temperature incubation for releasing growth factors. In conclusion, the freeze-thaw-freeze method is sufficient for releasing growth factors, and calcium activation is not necessary. Finally, the study demonstrates the possibility of preparing PRP products from platelet concentrates, so that preoperative blood sampling might not be required.

Bioactive treatments in bone grafts for implant-based rehabilitation: Systematic review and meta-analysis

BACKGROUND

The use of bioactive proteins, such as rhBMP-2, may improve bone regeneration in oral and maxillofacial surgery.

PURPOSE

Analyze the effect of using bioactive proteins for bone regeneration in implant-based rehabilitation.

MATERIALS AND METHODS

Seven databases were screened. Only clinical trials that evaluated the use of heterologous sources of bioactive proteins for bone formation prior to implant-based rehabilitation were included. Statistical analyses were carried out using a random-effects model by comparing the standardized mean difference between groups for bone formation, and risk ratio for implant survival (P ≤ .05).

RESULTS

Seventeen studies were included in the qualitative analysis, and 16 in the meta-analysis. For sinus floor augmentation, bone grafts showed higher amounts of residual bone graft particles than bioactive treatments (P ≤ .05). While for alveolar ridge augmentation bioactive treatments showed a higher level of bone formation than control groups (P ≤ .05). At 3 years of follow-up, no statistically significant differences were observed for implant survival (P > .05).

CONCLUSIONS

Bioactive proteins may improve bone formation in alveolar ridge augmentation, and reduce residual bone grafts in sinus floor augmentation. Further studies are needed to evaluate the long-term effect of using bioactive treatments for implant-based rehabilitation.

Evaluation of the Different Biomaterials Used in Alveolar Cleft Defects in Children

The aim of this study was to use a literature review to evaluate and compare the different biomaterials used in surgeries for the closure of the palatal and alveolar clefts as alternatives to isolated autografting. For the search strategy, the PubMed and Medline databases were used with the indexing terms "'cleft palate' (Mesh), 'biocompatible materials' (Mesh), and 'dentistry' (Mesh)." There was no restriction on language or publication time. After the research, 26 articles were found, and then, only the filter for clinical trials was selected. With this methodology, five articles were selected. The full texts have been carefully evaluated. The main issue among the five selected articles was the closure of a cleft palate and/or alveolar bone with the use of different types of biomaterials (e.g. autogenous bone from the iliac crest and chin, deproteinized bovine bone (DBB), β-tricalcium phosphate (β-TCP), synthetic resorption based on calcium sulfate, and the engineering of bone tissue); they evaluated preoperative and postoperative clinically and through imaging tests. The autogenous bone associated with DBB or β-TCP significantly reduces the amount of autogenous bone harvested from the iliac crest, morbidity, and the hospitalization of the patient, and the isolated use of bovine hydroxyapatite resulted in lower bone density compared to that from autogenous bone.

Reconstruction of Craniomaxillofacial Bone Defects Using Tissue-Engineering Strategies with Injectable and Non-Injectable Scaffolds

Engineering craniofacial bone tissues is challenging due to their complex structures. Current standard autografts and allografts have many drawbacks for craniofacial bone tissue reconstruction; including donor site morbidity and the ability to reinstate the aesthetic characteristics of the host tissue. To overcome these problems; tissue engineering and regenerative medicine strategies have been developed as a potential way to reconstruct damaged bone tissue. Different types of new biomaterials; including natural polymers; synthetic polymers and bioceramics; have emerged to treat these damaged craniofacial bone tissues in the form of injectable and non-injectable scaffolds; which are examined in this review. Injectable scaffolds can be considered a better approach to craniofacial tissue engineering as they can be inserted with minimally invasive surgery; thus protecting the aesthetic characteristics. In this review; we also focus on recent research innovations with different types of stem-cell sources harvested from oral tissue and growth factors used to develop craniofacial bone tissue-engineering strategies.

A historical perspective with current opinion on the management of atrophic mandibular fractures

The management of atrophic mandibular fractures has been a challenge for maxillofacial surgeons for decades. During the past 70 years, various techniques for treating edentulous mandibular fractures have been advocated. These techniques have been praised, criticized, abandoned, improved, and used in combination with other methods. Although some of the principles of management outlined before the end of World War II are still valid in today's technological era, other concepts did not survive the test of time. The aim of this paper is to examine the evolution of treatment modalities for the management of atrophic mandibular fractures that have been employed over the years. Debates and discussions generated by this topic are included. Current techniques and treatment philosophies with thoughts for future therapies are provided.

Atrophic Mandible Fractures: Are Bone Grafts Necessary? An Update

PURPOSE

The management of atrophic mandibular fractures poses a challenge because of anatomic variations and medical comorbidities associated with elderly patients. The purpose of this article is to review and update the literature regarding the management of atrophic mandible fractures using load-bearing reconstruction plates placed without bone grafts.

MATERIALS AND METHODS

We performed a review of the English-language literature looking for atrophic mandibular fractures with or without continuity defects and reconstruction without bone grafts. Included are 2 new patients from our institution who presented with fractures of their atrophic mandibles and had continuity defects and infections. Both patients underwent reconstruction with a combination of a reconstruction plate, recombinant human bone morphogenetic protein 2, and tricalcium phosphate. This study was approved as an "exempt study" by the Institutional Review Board at the University of Kentucky. This investigation observed the Declaration of Helsinki on medical protocol and ethics.

RESULTS

Currently, the standard of care to manage atrophic mandibular fractures with or without a continuity defect is a combination of a reconstruction plate plus autogenous bone graft. However, there is a need for an alternative option for patients with substantial comorbidities. Bone morphogenetic proteins, with or without additional substances, appear to be a choice. In our experience, successful healing occurred in patients with a combination of a reconstruction plate, recombinant human bone morphogenetic protein 2, and tricalcium phosphate.

CONCLUSIONS

Whereas primary reconstruction of atrophic mandibular fractures with reconstruction plates supplemented with autogenous bone graft is the standard of care, in selected cases in which multiple comorbidities may influence local and/or systemic outcomes, bone morphogenetic proteins and tricalcium phosphate can be used as a predictable alternative to autogenous grafts.