Autologous Bone Marrow Concentrates and Concentrated Growth Factors Accelerate Bone Regeneration After Enucleation of Mandibular Pathologic Lesions:

Biomimetic Tissue Engineering Strategies for Craniofacial Applications

Biomimetics is the science of imitating nature's designs and processes to create innovative solutions for various fields, including dentistry and craniofacial reconstruction. In these areas, biomimetics involves drawing inspiration from living organisms/systems to develop new materials, techniques, and devices that closely resemble natural tissue structures and enhance functionality. This field has successfully demonstrated its potential to revolutionize craniofacial procedures, significantly improving patient outcomes. In dentistry, biomimetics offers exciting possibilities for the advancement of new dental materials, restorative techniques, and regenerative potential. By analyzing the structure/composition of natural teeth and the surrounding tissues, researchers have developed restorative materials that mimic the properties of teeth, as well as regenerative techniques that might assist in repairing enamel, dentin, pulp, cementum, periodontal ligament, and bone. In craniofacial reconstruction, biomimetics plays a vital role in developing innovative solutions for facial trauma, congenital defects, and various conditions affecting the maxillofacial region. By studying the intricate composition and mechanical properties of the skull and facial bones, clinicians and engineers have been able to replicate natural structures leveraging computer-aided design and manufacturing (CAD/CAM) and 3D printing. This has allowed for the creation of patient-specific scaffolds, implants, and prostheses that accurately fit a patient's anatomy. This review highlights the current evidence on the application of biomimetics in the fields of dentistry and craniofacial reconstruction.

Comparison of the Effect of Platelet-rich Plasma (PRP) and Fat Graft on Autologous Bone Grafting in a Randomized-controlled Experimental Skull Model

Gold standard method for the treatment of critical-sized bone defects is the autogenous bone grafting procedure. A number of new and potentially useful adjuncts currently are being investigated to enhance the success of bone grafting. We propose to evaluate the effect of the most known and easily obtained 2 biological materials, fat graft and platelet-rich plasma (PRP), on bone graft healing. Twenty-seven New Zealand male rabbits were included in this randomized, controlled study. Two-sided 15-mm diameter bone defects were created in the parietal bones and the bones taken were replaced right-to-left and vice versa with 1 control group, 1 fat graft applied group, and the last one PRP applied group. Histologic evaluation and 3-dimensional maxillofacial computerized tomography were performed and bone density was calculated. In radiologic analysis, bone density was significantly different in the PRP group compared with the control and fat graft group in the 12th week ( P <0.05). In histologic scoring analysis, the PRP group had a better score than the control and fat graft group, while the fat graft group was worse than the control group in the 6th week ( P <0.05). The addition of PRP had a positive effect whereas fat graft had a negative effect on bone graft healing compared with the control group.

Novel Applications of Concentrated Growth Factors in Facial Rejuvenation and Plastic Surgery

Concentrated growth factor (CGF), which is a third-generation platelet concentrate product, exhibits good potential for repair and regeneration of soft and hard tissues, and has gradually attracted attention in the field of cosmetic plastic surgery. The purpose of this review is to summarize the application and research of CGF in the field of facial rejuvenation and plastic surgery. A comprehensive review of the literature about the applications of CGF in facial rejuvenation and plastic surgery was conducted in PubMed, Ovid MEDLINE, and Web of Science. According to the inclusion and exclusion criteria, a total of 22 articles were included in this review. In recent years, CGF has been applied in many aspects in the field of facial rejuvenation and plastic surgery, including skin photoaging, repairment of soft-tissue defects, rhinoplasty, hair loss, autologous fat transplantation, and scars. In addition, no significant adverse reactions have been reported so far. CGF is rich in high-concentration growth factors, which has great potential and application prospects in facial rejuvenation and plastic surgery. However, the applications of CGF still have some problems, such as the mechanism, time of decomposition, and long-term efficacy and safety, which are needed to be resolved in future.

Bone Tissue Engineering (BTE) of the Craniofacial Skeleton, Part II: Translational Potential of 3D-Printed Scaffolds for Defect Repair

Computer-aided design/computer-aided manufacturing and 3-dimensional (3D) printing techniques have revolutionized the approach to bone tissue engineering for the repair of craniomaxillofacial skeletal defects. Ample research has been performed to gain a fundamental understanding of the optimal 3D-printed scaffold design and composition to facilitate appropriate bone formation and healing. Benchtop and preclinical, small animal model testing of 3D-printed bioactive ceramic scaffolds augmented with pharmacological/biological agents have yielded promising results given their potential combined osteogenic and osteoinductive capacity. However, other factors must be evaluated before newly developed constructs may be considered analogous alternatives to the "gold standard" autologous graft for defect repair. More specifically, the 3D-printed bioactive ceramic scaffold's long-term safety profile, biocompatibility, and resorption kinetics must be studied. The ultimate goal is to successfully regenerate bone that is comparable in volume, density, histologic composition, and mechanical strength to that of native bone. In vivo studies of these newly developed bone tissue engineering in translational animal models continue to make strides toward addressing regulatory and clinically relevant topics. These include the use of skeletally immature animal models to address the challenges posed by craniomaxillofacial defect repair in pediatric patients. This manuscript reviews the most recent preclinical animal studies seeking to assess 3D-printed ceramic scaffolds for improved repair of critical-sized craniofacial bony defects.

Clinical observation of concentrated growth factor (CGF) combined with iliac cancellous bone and composite bone material graft on postoperative osteogenesis and inflammation in the repair of extensive mandibular defects

PURPOSE

To evaluate the effects of concentrated growth factor (CGF), combined with a mixture of iliac cancellous and composite bone materials, on the repair of extensive mandibular defects.

PATIENTS AND METHODS

This clinical trial involved patients with mandibular defects caused by large cystic lesions. The test group comprised 16 patients who underwent CGF combined with iliac cancellous bone and composite bone materials to repair extensive mandibular defects, whereas the control group comprised eight patients who underwent vascularised free fibula grafts for mandibular segmental defects. Postoperative exudatum was collected from patients on the 1st, 2nd, 3rd, and 4th days postoperatively, and osteogenic factor, including alkaline phosphatase (ALP), osteocalcin (BGP), and procollagen type I N-terminal propeptide (PINP), and inflammatory cytokines were performed. Additionally, regular cone beam computed tomography (CBCT) scans were conducted before and after surgery.

RESULTS

On postoperative days 1-4, the expression levels of ALP, BGP, and PINP were higher in the test group, while those of IL-1α, IL-1β, IL-6, IL-8, and TNF-α, which were identified as co-differentially expressing inflammatory cytokines, were all down-regulated in the exudatum of the test group. Regular CBCT radiological scans revealed a significant osteogenic effect in the test group.

CONCLUSION

The use of CGF combined with iliac cancellous bone and composite bone materials to repair extensive mandibular jaw defects facilitates bone formation and reductions in inflammation in the defect area in the short term, which deserves further research in clinical practice.

A case of concentrated growth factor gel to fill the defect after large jaw cyst enucleation

Management of large jaw cyst is challenging since high risks including pathologic fracture, limited opening, and insufficient bone healing occur after enucleation. The current case of concentrated growth factor (CGF) gel to fill defect after enucleation of large jaw cyst is rare. A 12-year-old boy with pain and swelling for 4 months in the left mandible region made a medical consultation at our hospital. Computerized tomography scan indicated that cystic lesion was found in the left mandible region. In this case, we present a patient with large jaw cyst (31 mm × 44 mm × 53 mm) who received enucleation followed by CGF gel filling the defect. The patient was discharged after 13 days without discomfort symptoms. The lesion size was reduced significantly at 1-month re-examination. No abnormality was detected in maxillofacial region at 1-year re-examination. Application of CGF gel is one of the possible options for filling defect after jaw cyst enucleation.

Bone Tissue Engineering (BTE) of the Craniofacial Skeleton, Part I: Evolution and Optimization of 3D-Printed Scaffolds for Repair of Defects

Bone tissue regeneration is a complex process that proceeds along the well-established wound healing pathway of hemostasis, inflammation, proliferation, and remodeling. Recently, tissue engineering efforts have focused on the application of biological and technological principles for the development of soft and hard tissue substitutes. Aim is directed towards boosting pathways of the healing process to restore form and function of tissue deficits. Continued development of synthetic scaffolds, cell therapies, and signaling biomolecules seeks to minimize the need for autografting. Despite being the current gold standard treatment, it is limited by donor sites' size and shape, as well as donor site morbidity. Since the advent of computer-aided design/computer-aided manufacturing (CAD/CAM) and additive manufacturing (AM) techniques (3D printing), bioengineering has expanded markedly while continuing to present innovative approaches to oral and craniofacial skeletal reconstruction. Prime examples include customizable, high-strength, load bearing, bioactive ceramic scaffolds. Porous macro- and micro-architecture along with the surface topography of 3D printed scaffolds favors osteoconduction and vascular in-growth, as well as the incorporation of stem and/or other osteoprogenitor cells and growth factors. This includes platelet concentrates (PCs), bone morphogenetic proteins (BMPs), and some pharmacological agents, such as dipyridamole (DIPY), an adenosine A 2A receptor indirect agonist that enhances osteogenic and osteoinductive capacity, thus improving bone formation. This two-part review commences by presenting current biological and engineering principles of bone regeneration utilized to produce 3D-printed ceramic scaffolds with the goal to create a viable alternative to autografts for craniofacial skeleton reconstruction. Part II comprehensively examines recent preclinical data to elucidate the potential clinical translation of such 3D-printed ceramic scaffolds.

Progress in Regenerative Medicine: Exploring Autologous Platelet Concentrates and Their Clinical Applications

The goal of regenerative medicine is to achieve tissue regeneration. In the past, commonly used techniques included autologous or allogeneic transplantation and stem cell therapy, which have limitations, such as a lack of donor sites in the case of autologous transplantation and the invasiveness of stem cell harvesting. In recent years, research has, therefore, focused on new and less invasive strategies to achieve tissue regeneration. A step forward in this direction has been made with the development of autologous platelet concentrates (APCs), which are derived from the patient's own blood. They can be classified into three generations: platelet-rich plasma (PRP), platelet-rich fibrin (PRF), and concentrated growth factors (CGFs). These APCs have different structural characteristics, depending on the distinctive preparation method, and contain platelets, leukocytes, and multiple growth factors, including those most involved in regenerative processes. The purpose of this review is to clarify the most used techniques in the field of regenerative medicine in recent years, comparing the different types of APCs and analyzing the preparation protocols, the composition of the growth factors, the level of characterization achieved, and their clinical applications to date.

Three-Dimensional Printing Bioceramic Scaffolds Using Direct-Ink-Writing for Craniomaxillofacial Bone Regeneration

Defects characterized as large osseous voids in bone, in certain circumstances, are difficult to treat, requiring extensive treatments which lead to an increased financial burden, pain, and prolonged hospital stays. Grafts exist to aid in bone tissue regeneration (BTR), among which ceramic-based grafts have become increasingly popular due to their biocompatibility and resorbability. BTR using bioceramic materials such as β-tricalcium phosphate has seen tremendous progress and has been extensively used in the fabrication of biomimetic scaffolds through the three-dimensional printing (3DP) workflow. 3DP has hence revolutionized BTR by offering unparalleled potential for the creation of complex, patient, and anatomic location-specific structures. More importantly, it has enabled the production of biomimetic scaffolds with porous structures that mimic the natural extracellular matrix while allowing for cell growth-a critical factor in determining the overall success of the BTR modality. While the concept of 3DP bioceramic bone tissue scaffolds for human applications is nascent, numerous studies have highlighted its potential in restoring both form and function of critically sized defects in a wide variety of translational models. In this review, we summarize these recent advancements and present a review of the engineering principles and methodologies that are vital for using 3DP technology for craniomaxillofacial reconstructive applications. Moreover, we highlight future advances in the field of dynamic 3D printed constructs via shape-memory effect, and comment on pharmacological manipulation and bioactive molecules required to treat a wider range of boney defects.

Ex Vivo Preservation of Ovine Periosteum Using a Perfusion Bioreactor System

Periosteum is a highly vascularized membrane lining the surface of bones. It plays essential roles in bone repair following injury and reconstruction following invasive surgeries. To broaden the use of periosteum, including for augmenting in vitro bone engineering and/or in vivo bone repair, we have developed an ex vivo perfusion bioreactor system to maintain the cellular viability and metabolism of surgically resected periosteal flaps. Each specimen was placed in a 3D printed bioreactor connected to a peristaltic pump designed for the optimal flow rates of tissue perfusate. Nutrients and oxygen were perfused via the periosteal arteries to mimic physiological conditions. Biochemical assays and histological staining indicate component cell viability after perfusion for almost 4 weeks. Our work provides the proof-of-concept of ex vivo periosteum perfusion for long-term tissue preservation, paving the way for innovative bone engineering approaches that use autotransplanted periosteum to enhance in vivo bone repair.

Platelet-rich fibrin combined with new bone graft material for mandibular defect repair: A in vivo study on rabbits

Insufficient bone mass is still a difficult point to be solved in oral implantation, so new bone graft materials are continuously researched and discussed in clinical practice in order to obtain better bone augmentation. In order to explore whether platelet-rich fibrin (PRF) can promote the formation of new bone in mineralized collagen (MC), MC/PRF and pure MC were implanted into the bilateral mandibular defect model in rabbits, respectively. Micro-CT scan and histological evaluation of the target area at 4, 8, and 12 weeks after operation. The results of Micro-CT three-dimensional reconstruction analysis showed that the ratio of bone volume to total volume (BV/TV), trabecular bone number (Tb.N), trabecular bone thickness (Tb.Th) and trabecular bone separation (Tb.Sp) and residual material volume fraction (RMVF) in the MC/PRF group were better than those in the MC group (p<0.05). The results of HE and Masson staining showed that the new bone formation and material degradation rate of the MC/PRF group were better than those of the MC group. The results suggest that PRF can accelerate the formation of new bone in MC, and provide new ideas for the clinical application of new bone graft materials.

Clinical application of mesenchymal stem cell in regenerative medicine: a narrative review

The multipotency property of mesenchymal stem cells (MSCs) has attained worldwide consideration because of their immense potential for immunomodulation and their therapeutic function in tissue regeneration. MSCs can migrate to tissue injury areas to contribute to immune modulation, secrete anti-inflammatory cytokines and hide themselves from the immune system. Certainly, various investigations have revealed anti-inflammatory, anti-aging, reconstruction, and wound healing potentials of MSCs in many in vitro and in vivo models. Moreover, current progresses in the field of MSCs biology have facilitated the progress of particular guidelines and quality control approaches, which eventually lead to clinical application of MSCs. In this literature, we provided a brief overview of immunoregulatory characteristics and immunosuppressive activities of MSCs. In addition, we discussed the enhancement, utilization, and therapeutic responses of MSCs in neural, liver, kidney, bone, heart diseases, and wound healing.

A comparative study of the effects of platelet-rich fibrin, concentrated growth factor and platelet-poor plasma on the healing of tooth extraction sockets in rabbits

BACKGROUND

Autologous platelet concentrate has been widely used to encourage the regeneration of hard and soft tissues. Up to now, there are three generations of autologous platelet concentrates. Many studies have shown that the three autologous concentrates have different effects, but the specific diversities have not been studied. The purpose of this study was to explore and compare the effects of platelet-rich fibrin, concentrated growth factor and platelet-poor plasma on the healing of tooth extraction sockets in New Zealand rabbits.

METHODS

A total of 24 healthy male New Zealand white rabbits aged 8-12 weeks were selected. The experimental animals were randomly divided into four groups: three experimental groups were respectively implanted with PPP, CGF and PRF gel after bilateral mandibular anterior teeth were extracted, and the control group did not implant any material. The alveolar bone of the mandibular anterior region was taken at 2, 4 and 8 weeks after operation. The height and width of the extraction wound were detected by CBCT, the growth of the new bone was observed by HE and Masson staining, and the expression of osteogenic genes was detected by real-time PCR. Data were analyzed using IBM SPSS statistical package 22.0.

RESULTS

The radiological results showed that alveolar bone resorption in all groups gradually increased over time. However, the experimental groups showed lower amounts of bone resorption. The histological results showed that new bone formation was observed in all groups. Over time, the new bone trabeculae of the CGF group became closely aligned while those in the PPP and PRF groups remained scattered. PCR results showed that the expression of BMP-2 and ALP was higher in the experimental groups than the control group.

CONCLUSION

In conclusion, the application of PRF, CGF and PPP in tooth extraction sockets effectively promoted bone regeneration. CGF showed more effective bone induction and tissue regeneration ability in the long term.

Platelet-Rich Plasma for Bone Fracture Treatment: A Systematic Review of Current Evidence in Preclinical and Clinical Studies

Background: Recently, there is an increasing interest in the therapeutic potential of platelet-rich plasma (PRP) for bone fracture treatment. Nevertheless, the effect of PRP for bone fracture treatment remains controversial and is still a matter of discussion. Therefore, we performed a systematic review to evaluate the efficacy and safety of PRP injection for treatment of bone fracture. Methods: The main bibliographic databases, including Medline, PubMed, Embase, Web of Science, and the Cochrane library, were comprehensively searched for studies focusing on the application of platelet-rich plasma (PRP) on bone fracture treatment. All relevant articles were screened for eligibility and subdivided into the preclinical and clinical studies. Data were extracted and presented systematically. Results: Finally, twenty-six in vitro preclinical studies (basic studies), nine in vivo preclinical studies (animal studies), and nine clinical studies, met the selection criteria, and were included in the present systematic review. Preclinical studies showed an overall positive effect of PRP on osteoblast-like cells in vitro and bone healing in animal models. The most used treatment for bone fracture in animal and clinical studies is fixation surgery combined with PRP injection. The clinical studies reported PRP shortened bony healing duration, and had no positive effect on improving the healing rate of closed fractures. However, the results of functional outcomes are controversial. Additionally, compared with control group, PRP would not increase the rate of postoperative wound infection. Conclusion: The present systematic review confirmed the continuing interests of PRP as an additional treatment for bone fracture. Preclinical studies highlighted the potential value of PRP as promising therapy for bone fracture. However, the preclinical evidence did not translate into a similar result in the clinical studies. In addition, types of fractures and procedures of PRP preparation are heterogeneous in enrolled studies, which might result in controversial results. Meanwhile, characteristics of PRP, such as platelet concentration, the numbers of leukocytes, still need to be determined and further research is required.

CGF Membrane Promotes Periodontal Tissue Regeneration Mediated by hUCMSCs through Upregulating TAZ and Osteogenic Differentiation Genes

Concentrated growth factor (CGF) membranes are widely used in basic and clinical research of soft and hard tissue regeneration, but its effect on periodontal tissue regeneration is less studied. This study explored the role of CGF membranes in periodontal tissue regeneration mediated by human umbilical cord mesenchymal stem cells (hUCMSCs). HUCMSCs and human periodontal ligament fibroblasts (HPLFs) were extracted and identified by microscope and flow cytometry. The effects of the extracted CGF membrane on cell viability, osteogenic differentiation ability, osteopontin (OPN) expression, alkaline phosphatase (ALP) content, and osteogenic differentiation-related genes (Runt-related transcription factor 2 (RUNX2); osteocalcin (OCN); ALP), Tafazzin (TAZ) expression, and nuclear transfer were examined by MTT assay, alizarin red staining, immunofluorescence, enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), and Western blot. Rescue experiments were performed to examine the effects of TAZ transfection and cell coculture. In the identified hUCMSCs (positive expressions of CD29, CD44, CD146, and CD105), overexpressed TAZ (pc-TAZ) enhanced the promotive effect of CGF membrane on cell viability, cell cycle, mineralization, ALP content and expressions of OPN, TAZ and osteogenic differentiation-related genes, and nuclear transfer. However, silencing TAZ showed opposite effects. The coculture of hUCMSCs and HPLFs further promoted the basic biological functions of HPLFs by upregulating osteogenic differentiation-related genes and COL-1 but downregulated MMP1 expression. Pc-TAZ could enhance the effect of CGF membrane on promoting periodontal tissue regeneration. CGF membrane promoted periodontal tissue regeneration through upregulating TAZ and osteogenic differentiation-related genes.

Autologous bone marrow aspirate concentrate (BMAC) for treatment of keratocystic odontogenic tumour (KCOT)-a case report

Management of keratocystic odontogenic tumor (KCOT) has always remained a conundrum due to its aggressive behavior, indicating wide resection. Achieving an esthetically and functionally acceptable reconstruction remains a challenge. Herein, we present a novel and less invasive technique for the treatment of KCOT. A 55-year-old female presenting with pain in the lower jaw for the past 3 months was diagnosed with a large KCOT extending from 35 to 47 region. CT images revealed buccal and lingual cortical bone erosion. Management was done in two stages: cyst curettage and chemical cauterization, followed by application of Bone Marrow Aspirate Concentrate (BMAC) with a delay of two months, to increase the thickness of eroded cortical bone. On follow-up at one year, ossification of the defect was observed. BMAC is a cocktail of mesenchymal stromal cells, hematopoietic stem cells, fibroblasts, mononuclear cells, macrophages, endothelial cells, progenitor cells, growth factors and cytokines. BMAC cocktail provide an anti-inflammatory, anti-fibrotic, anti-apoptotic, and immunomodulatory environment. Autologous platelet rich plasma provides various growth factors (TGF-β, PDGF, EGF, HGF, NGF, IGF-1) and cytokines. Addition of PRP in BMAC cocktail enhance the regeneration of tissues, where PRP act as a functional regenerative scaffold for cell integration, proliferation, and differentiation that can expedite macroscale musculoskeletal tissue healing. Autologous BMAC with corticocancellous bone acts as an osteoconductive scaffold capable of regenerating the large bone defect created by the curettage of KCOT.

Biomimetic Aspects of Oral and Dentofacial Regeneration

Biomimetic materials for hard and soft tissues have advanced in the fields of tissue engineering and regenerative medicine in dentistry. To examine these recent advances, we searched Medline (OVID) with the key terms “biomimetics”, “biomaterials”, and “biomimicry” combined with MeSH terms for “dentistry” and limited the date of publication between 2010–2020. Over 500 articles were obtained under clinical trials, randomized clinical trials, metanalysis, and systematic reviews developed in the past 10 years in three major areas of dentistry: restorative, orofacial surgery, and periodontics. Clinical studies and systematic reviews along with hand-searched preclinical studies as potential therapies have been included. They support the proof-of-concept that novel treatments are in the pipeline towards ground-breaking clinical therapies for orofacial bone regeneration, tooth regeneration, repair of the oral mucosa, periodontal tissue engineering, and dental implants. Biomimicry enhances the clinical outcomes and calls for an interdisciplinary approach integrating medicine, bioengineering, biotechnology, and computational sciences to advance the current research to clinics. We conclude that dentistry has come a long way apropos of regenerative medicine; still, there are vast avenues to endeavour, seeking inspiration from other facets in biomedical research.

Considerations for Clinical Use of Concentrated Growth Factor in Maxillofacial Regenerative Medicine

Different strategies have been utilized to facilitate mineralized/soft tissues. Concentrated growth factor (CGF) emerges as a promising biomaterial for regenerative therapy due to high levels of platelets, growth factors, and nucleated cells entrapped in the fibrin scaffold. This review aimed to collect extensive studies on CGF used in maxillofacial regenerative medicine, discussing current obstacles, and expressing some considerations of CGF use. Articles were retrieved systematically without time limitation. In total, 27 human studies were included and separated accordingly. In general, CGF has been most evaluated in implant related therapy and maxillofacial bone regeneration where a majority of articles have revealed favorable outcomes. Little studies have supported the effects on improving probing periodontal depth reductions and clinical attachment level gains for intrabony and furcation defect regeneration. Very little data with high-level evidence was available directly to investigate its effects on the soft tissue regeneration and postoperative complications reduction. The evidence supporting the clinical efficacy of CGF in maxillofacial regenerative medicine is limited. Some conflicting results are worrisome. In addition, the characterization of CGF preparation protocols and CGF's components was not performed in most studies. Further studies should make a consensus on standardized end-product of CGF including characterization of protocols and optimal ratio of CGF' components. Defined algorithms and evidence-based protocols for the clinical use of CGF should be also available.

Does Concentrated Growth Factor Used With Allografts in Maxillary Sinus Lifting Have Adjunctive Benefits?

PURPOSE

Recent studies have shown that the use of platelet concentration products alone, or in combination with variable graft materials, accelerates the new bone formation associated with sinus augmentation. The aim of this study was to measure the adjunctive effects of concentrated growth factor (CGF) used with allograft on new bone formation and augmentation stability in sinus lifting.

MATERIALS AND METHODS

This randomized controlled study included patients who presented for dental implant placement in atrophic posterior maxilla at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Ege University, and who needed maxillary sinus augmentation. All patients were treated with a 2-stage surgical technique using sinus lifting bilaterally and implant placement 6 months later. During sinus lifting surgery, one side was grafted with allograft (group 1) and the other side with allograft mixed CGF (group 2). Cone-beam computed tomography was carried out immediately postoperatively and also 6 months after the augmentation to evaluate vertical bone height and percentage of resorption. Bone specimens were obtained at the time of implant placement and evaluated histomorphometrically to analyze the percentage of new bone formation and residual graft particle. Statistical comparisons were conducted between groups for all these measurements.

RESULTS

A total of 10 patients (2 females and 8 males) with a mean age of 57 years (range, 39 to 72) were enrolled in the study. Cone-beam computed tomography analysis revealed a significantly higher percentage of bone height resorption at the sixth month in group 1 (median, 9.32%) compared with group 2 (median, 6.37%) (P < .05). According to the histomorphometric examination, the percentage of new bone formation in group 2 (median, 36.41%) was higher than group 1 (median, 35.49%), but this difference did not reach statistical significance.

CONCLUSIONS

Using CGF with allografts supports the stabilization of gained vertical bone height after sinus augmentation, but further research is needed to determine the accelerating effects of CGF on new bone formation.

A Comprehensive Review of Concentrated Growth Factors and Their Novel Applications in Facial Reconstructive and Regenerative Medicine

BACKGROUND

Concentrated growth factors (CGFs) are the latest generation of platelet concentrates. The objective of developing CGF is to increase therapeutic efficacy. However, few studies have supported the superiority of CGF in composition and efficacy. The reconstruction and regeneration process is complicated and long term, whereas bioactivity of CGF is not durable. The purpose of this review is threefold. The first is to recommend more comparative studies between CGF and other platelet concentrates. The second is to constitute a continuous drug delivery system by combining CGF with other biomaterials. Finally, the novel use of CGF in facial regenerative and reconstructive medicine will be highlighted.

METHODS

A comprehensive review of literature regarding the use of CGF in facial regenerative and reconstructive medicine was performed. Based on the inclusion and exclusion criteria, a total of 135 articles were included.

RESULTS

The use of CGF involving facial rejuvenation, cartilage grafting, facial bone defects, facial peripheral nerve injury and wounding is reviewed. The reconstructive and regenerative principles lie in firm fibrin scaffolds and continuous in situ delivery of multiple growth factors.

CONCLUSIONS

CGF represents an advance in personalized medicine concept. However, the current scientific evidences about the use of CGF are limited. More basic and clinical studies should be conducted to understand the characteristics and clinical application of CGF.

LEVEL OF EVIDENCE V

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Clinical Application of Concentrated Growth Factor Fibrin Combined With Bone Repair Materials in Jaw Defects

PURPOSE

We investigated the promoting effect of concentrated growth factor (CGF) fibrin on the repair of jaw bone defects.

PATIENTS AND METHODS

We designed a clinical trial composed of patients with jaw defects. Forty patients were divided into the test and control groups. CGF fibrin combined with Bio-Oss bone powder (Giestlich Pharma, Wolhusen, Switzerland) was used in the test group. Bio-Oss bone powder alone was used in the control group. The concentration of vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-β in the red blood cell (RBC) layer and CGF gel was measured. At different time points before and after surgery, the serum bone alkaline phosphatase (BAP), osteocalcin, and bone mineral density levels were measured. Regular examinations and computed tomography scans were also performed in the follow-up period.

RESULTS

The CGF fibrin available for clinical use was obtained by centrifugation. One day after preparation by centrifugation, the VEGF and TGF-β concentration in the CGF gel was 2.57-fold and 3.4-fold greater than the concentration in the RBC layer, respectively. The BAP and osteocalcin levels increased at 1 and 12 weeks postoperatively in both groups. Furthermore, the BAP and osteocalcin levels in the test group were significantly greater than those in the control group at 1 and 12 weeks postoperatively (P < .05 for all). The bone mineral density in the bone defect area of the test group was also significantly greater than that of the control group at 6 months postoperatively (P < .05). Evaluation of the regular radiographic scans revealed that the effects in the test group were better than those in the control group.

CONCLUSIONS

CGF fibrin could promote new bone formation in jaw defects, with benefit to the healing of bone tissue and, thus, is a promising bone repair material.

Biofunctionalization of porcine-derived collagen matrices with platelet rich fibrin: influence on angiogenesis in vitro and in vivo

Objectives

Porcine-derived collagen matrices (CM) can be used for oral tissue regeneration, but sufficient revascularization is crucial. The aim of this study was to analyze the influence of platelet-rich fibrin (PRF) on angiogenesis of different CM in vitro and in vivo.

Materials and methods

Three different CM (mucoderm, jason, collprotect) were combined with PRF in a plotting process. Growth factor release (VEGF, TGF-β) was measured in vitro via ELISA quantification after 1,4 and 7 days in comparison to PRF alone. In ovo yolk sac (YSM) and chorion allantois membrane (CAM) model, angiogenic potential were analyzed in vivo with light- and intravital fluorescence microscopy after 24 h, then verified with immunohistochemical staining for CD105 and αSMA.

Results

Highest growth factor release was seen after 24 h for all three activated membranes in comparison to the native CM (VEGF 24 h: each p < 0.05; TGF-β: each p < 0.001) and the PRF (no significant difference). All activated membranes revealed a significantly increased angiogenic potential in vivo after 24 h (vessels per mm2: each p < 0.05; branching points per mm2: each p < 0.01; vessel density: each p < 0.05) and with immunohistochemical staining for CD105 (each p < 0.01) and αSMA (each p < 0.05).

Conclusions

PRF improved the angiogenesis of CM in vitro and in vivo.

Clinical relevance

Bio-functionalization of CM with PRF could easily implemented in the clinical pathway and may lead to advanced soft tissue healing.

Anthropometric Analysis of Secondary Cleft Lip Rhinoplasty Using Costal Cartilage Graft

Despite the improvement of primary repair of nasal deformities during the management of cleft lip in infancy, this does not exclude the need for revision rhinoplasty in adulthood for complete patients' rehabilitation. The purpose of this study was to evaluate the aesthetic outcome of secondary rhinoplasty using costal cartilage grafts in patients with unilateral cleft lip nasal deformity. Twenty patients who were operated at earlier ages for correction of cleft lip and had a residual unilateral cleft lip nasal deformity were included in this study. Costal cartilage rib grafts were harvested; carved and used for maxillary augmentation, columellar strut graft, and lateral crural strut graft. Five anthropometric measurements (nostril height, width and gap area, columellar axis deviation angle and nasal base inclination angle) were used for evaluation of aesthetic results. The ratio of nostril width, height and gap area between the cleft side and the non-cleft side showed significant improvement (P <0.05). The columellar axis deviation showed significant improvement towards the midline (P = 0.004), and the alar base inclination showed improvement towards the horizontal line (P = 0.0045). In conclusion, the aesthetic outcomes of secondary cleft lip rhinoplasty using the costal cartilage are satisfactory. The costal cartilage has the required strength, is easily carved and maintains shape for considerable time.

Bone Tissue Regeneration in the Oral and Maxillofacial Region: A Review on the Application of Stem Cells and New Strategies to Improve Vascularization

Bone tissue engineering techniques are a promising alternative for the use of autologous bone grafts to reconstruct bone defects in the oral and maxillofacial region. However, for successful bone regeneration, adequate vascularization is a prerequisite. This review presents and discusses the application of stem cells and new strategies to improve vascularization, which may lead to feasible clinical applications. Multiple sources of stem cells have been investigated for bone tissue engineering. The stromal vascular fraction (SVF) of human adipose tissue is considered a promising single source for a heterogeneous population of essential cells with, amongst others, osteogenic and angiogenic potential. Enhanced vascularization of tissue-engineered grafts can be achieved by different mechanisms: vascular ingrowth directed from the surrounding host tissue to the implanted graft, vice versa, or concomitantly. Vascular ingrowth into the implanted graft can be enhanced by (i) optimizing the material properties of scaffolds and (ii) their bioactivation by incorporation of growth factors or cell seeding. Vascular ingrowth directed from the implanted graft towards the host tissue can be achieved by incorporating the graft with either (i) preformed microvascular networks or (ii) microvascular fragments (MF). The latter may have stimulating actions on both vascular ingrowth and outgrowth, since they contain angiogenic stem cells like SVF, as well as vascularized matrix fragments. Both adipose tissue-derived SVF and MF are cell sources with clinical feasibility due to their large quantities that can be harvested and applied in a one-step surgical procedure. During the past years, important advancements of stem cell application and vascularization in bone tissue regeneration have been made. The development of engineered in vitro 3D models mimicking the bone defect environment would facilitate new strategies in bone tissue engineering. Successful clinical application requires innovative future investigations enhancing vascularization.