Platelet-Rich Fibrin as a Bone Graft Material in Oral and Maxillofacial Bone Regeneration: Classification and Summary for Better Application.

Platelet-rich fibrin (PRF) is an autologous platelet concentrate that consists of cytokines, platelets, leukocytes, and circulating stem cells. It has been considered to be effective in bone regeneration and is mainly used for oral and maxillofacial bone. Although currently the use of PRF is thought to support alveolar ridge preservation, there is a lack of evidence regarding the application of PRF in osteogenesis. In this paper, we will provide examples of PRF application, and we will also summarize different measures to improve the properties of PRF for achieving better osteogenesis. The effect of PRF as a bone graft material on osteogenesis based on laboratory investigations, animal tests, and clinical evaluations is first reviewed here. In vitro, PRF was able to stimulate cell proliferation, differentiation, migration, mineralization, and osteogenesis-related gene expression. Preclinical and clinical trials suggested that PRF alone may have a limited effect. To enlighten researchers, modified PRF graft materials are further reviewed, including PRF combined with other bone graft materials, PRF combined with drugs, and a new-type PRF. Finally, we will summarize the common shortcomings in the application of PRF that probably lead to application failure. Future scientists should avoid or solve these problems to achieve better regeneration.

Enxerto ósseo em bloco autógeno na maxila: relato de caso clínico / Autogenous block bone graft in the upper jaw: report of case

A instalação de implantes em áreas com perda óssea pode estar associada a uma relação coroa-implante desfavorável, resultado estético insatisfatório e dificuldades de higienização, prejudicando o prognóstico do tratamento. O enxerto ósseo possibilita a instalação de implantes em uma posição tridimensional favorável. Alguns métodos têm sido estudados e propostos para a reconstrução do osso alveolar perdido: enxertos ósseos autógenos, homógenos, substitutos ósseos alógenos, xenógenos e aloplásticos. Ainda existe a regeneração óssea guiada, distração osteogênica, fatores de crescimento e as combinações destas referidas metodologias. Dentre os materiais disponíveis, o osso autógeno é tido como primeira opção para a reconstrução óssea,tido como padrão ouro em enxertia óssea, pois fornece as condições mais favoráveis de reparo pós-cirúrgico, por apresentar as propriedades de osteocondução, osteoindução e osteogênese,auxiliando na correção de defeitos de espessura, desde que haja um bom suprimento vascular no local. Neste trabalho é demonstrada uma técnica de enxertia óssea em bloco autógeno, através da realização de um caso clínico, para a reconstrução de maxila atrófica, visando o aumento do volume ósseo disponível para a instalação de implantes dentais.

The installation of implants in areas of bone loss may be associated with an unfavorable ratiocrown-implant, unsatisfactory aesthetic result and cleaning difficulties, impairing treatment prognosis. The bone graft allows the installation of implants in a favorable three-dimensional position. Some methods have been studied and proposed for the reconstruction of lost alveolar bone: autogenous bone grafts, homogeneous bone, allogenic, xenogenous and alloplasticbone substitutes. There is still the guided bone regeneration, distraction osteogenesis, growth factors and combinations of these referred methodologies. Among the materials available, the autogenous bone is considered as the first option for bone reconstruction, considered the gold standard in bone grafting because it provides the most favorable conditions for post-surgical repair, presenting the properties of osteoconductive, osteoinductive and osteogenesis, helping the correction of the defects of thickness, since there is a good blood supply in the area. Thiswork shows a bone grafting technique in autogenous block by performing a case for the reconstruction of atrophic maxilla, in order to increase bone volume available for the installation of dental implants.

Ordinary and Activated Bone Grafts: Applied Classification and the Main Features.

Bone grafts are medical devices that are in high demand in clinical practice for substitution of bone defects and recovery of atrophic bone regions. Based on the analysis of the modern groups of bone grafts, the particularities of their composition, the mechanisms of their biological effects, and their therapeutic indications, applicable classification was proposed that separates the bone substitutes into "ordinary" and "activated." The main differential criterion is the presence of biologically active components in the material that are standardized by qualitative and quantitative parameters: growth factors, cells, or gene constructions encoding growth factors. The pronounced osteoinductive and (or) osteogenic properties of activated osteoplastic materials allow drawing upon their efficacy in the substitution of large bone defects.

Flow-through flap for salvage of fibula osseocutaneous vascular variations: a surgical approach and proposed modification of its classification.

The osseocutaneous fibula free flap is commonly used in mandibular reconstruction. Clinically important anatomic variants of the donor vessels have been reported. The authors describe a rare variant encountered while raising an osseocutaneous fibula flap. The fibula was supplied by the peroneal vessels and the overlying skin paddle was supplied by musculocutaneous perforators arising from the posterior tibial vessels. By raising 2 separate free flaps and configuring them in microvascular series with the fibula acting as a flow-through flap, the reconstruction was successful. Although the anatomic variant has been described, the authors' approach to it has not. The benefits of this method over other options include preservation of a skin paddle for monitoring and watertight oral closure and a long pedicle to the skin paddle permitting a wide arc of movement. The authors suggest a modification to the existing classification of perforators to the lateral leg skin to guide intraoperative decision making.

Evaluation of healing following tooth extraction with ridge preservation using cortical versus cancellous freeze-dried bone allograft.

BACKGROUND: The objective of this study is to compare histologic and clinical healing following tooth extraction and ridge preservation with either cortical or cancellous freeze-dried bone allograft (FDBA) in non-molar extraction sockets. METHODS: Forty patients requiring implant placement were enrolled, with 20 patients randomly assigned to each group (cortical versus cancellous FDBA). All of the allograft materials were obtained from the same donor to control for variability between donors and processing. Patients returned after 17 to 21 weeks (average: 18.2 weeks), and a 2-mm-diameter core biopsy was obtained before implant placement. Histomorphometric analysis was performed to determine percentage of new bone formation, residual graft material, and non-mineralized connective tissue (CT)/other material. Clinical measurements of ridge dimensions were taken at the time of tooth extraction and again at implant placement. RESULTS: There was no significant difference in new bone formation between the cortical and cancellous FDBA groups (P = 0.857). A significantly greater percentage of residual graft material was detected in the cortical FDBA group compared with the cancellous FDBA group (P = 0.019). A significantly greater percentage of non-mineralized CT/other material was found in the cancellous FDBA group compared with the cortical FDBA group (P = 0.040). The only significant clinical difference between groups was a greater loss of lingual ridge height in the cancellous group. CONCLUSIONS: This is the first reported study to compare the histologic changes following tooth extraction with ridge preservation in humans using cortical versus cancellous FDBA. There were no differences in the percentage of new bone formation between the groups.

Clinical application of the FACES score for face transplantation.

OBJECTIVE: This study aimed to systematically evaluate all reported outcomes of facial allotransplantation (FT) using the previously described FACES scoring instrument. METHODS: This was a retrospective study of all consecutive face transplants to date (January 2012). Candidates were identified using medical and general internet database searches. Medical literature and media reports were reviewed for details regarding demographic, operative, anatomic, and psychosocial data, which were then used to formulate FACES scores. Pre-transplant and post-transplant scores for "functional status", "aesthetic deformity", "co-morbidities", "exposed tissue", and "surgical history" were calculated. Scores were statistically compared using paired-samples analyses. RESULTS: Twenty consecutive patients were identified, with 18 surviving recipients. The sample was composed of 3 females and 17 males, with a mean age of 35.0 ± 11.0 years (range: 19-57 years). Overall, data reporting for functional parameters was poor. Six subjects had complete pre-transplant and post-transplant data available for all 5 FACES domains. The mean pre-transplant FACES score was 33.5 ± 8.8 (range: 23-44); the mean post-transplant score was 21.5 ± 5.9 (range: 14-32) and was statistically significantly lower than the pre-transplant score (P = 0.02). Among the individual domains, FT conferred a statistically significant improvement in aesthetic defect scores and exposed tissue scores (P ≤ 0.01) while, at the same time, it displayed no significant increases in co-morbidity (P = 0.17). CONCLUSION: There is a significant deficiency in functional outcome reports thus far. Moreover, FT resulted in improved overall FACES score, with the most dramatic improvements noted in aesthetic defect and exposed tissue scores.

Long-term bony integration and resorption kinetics of a xenogeneic bone substitute after sinus floor augmentation: histomorphometric analyses of human biopsy specimens.

In this case series, a systematic histomorphometric analysis of two human bone biopsy specimens was conducted 1 and 5 years after grafting with a xenogeneic bovine bone substitute material (BSM). While the 1-year specimen still showed extensive signs of an active desmal ossification, the specimen after 5 years mainly showed mature lamellar bone without bone turnover or remodeling. A completed bony integration without extensive resorption of the BSM particles could be detected. Altogether, a good integration in the bone with osteoconduction and a high biocompatibility was seen.

Early bone resorption after vertical bone augmentation--a comparison of calvarial and iliac grafts.

OBJECTIVE AND AIM: Severe cases of bone atrophy in the maxilla or mandible are often reconstructed using bone from extraoral donor sides. Most commonly, grafts from the iliac crest are used for augmentation, however, frequently associated with bone resorption as possible late complication. Calvarial bone grafts, often reported to show less resorption, are an alternative. The aim of this study was to compare the bone stability of vertical bone grafts from the iliac crest and the calvarium. PATIENTS AND METHODS: Twenty-three patients receiving vertical onlay bone grafts were included in this retrospective cohort study. In nine patients alveolar ridge defects were treated with bone from the iliac crest. Fourteen patients were reconstructed using calvarial bone grafts. To quantify bone resorption, the data of digital panographs were evaluated. Radiographs were taken prior to bone grafting, after augmentation surgery, 6 months after bone healing, prior to implant surgery, after implant surgery and at yearly intervals thereafter. RESULTS: Postoperative complications at the recipient site occurred equally in both groups. The complication rate was 35.7% for the calvarial group and 33.3% in the iliac crest group. No donor-site complications were reported in either group. After bone augmentation procedure, a mean vertical bone gain of 8.55 mm (SD 5.96) was measured. Bone grafts from the iliac crest showed a significantly higher bone loss of 24.16% (SD 8.47) than grafts from the calvarium (8.44%, SD 3.64) at the time of implant placement (P = 0.0003). Implant survival was similar in both groups. DISCUSSION: Both bone-grafting approaches are successful and reliable techniques, enabling implant placement in even highly atrophied alveolar ridges and with identical implant survival rates, although bone resorption differs. Within the limitations of this study bone from the calvarium shows higher bone stability in the early healing phase.

Clinical similarities and histological diversity comparing fresh frozen onlay bone blocks allografts and autografts in human maxillary reconstruction.

BACKGROUND: In the absence of autologous bone for harvesting, fresh-frozen bone allografts turned into an alternative for bone reconstruction procedures. PURPOSE: The purpose of this study was to make a histological analysis of fresh-frozen onlay bone allografts (ALs), compared with autografts, in patients who needed maxillary reconstruction prior to dental implants placement. MATERIALS AND METHODS: Twelve patients with bone deficiencies (width inferior to 4 mm) in the sites where the implants were planned were enrolled in the study. From these, six were elected to be treated with autogenous (AT) bone grafts and six with fresh-frozen bone AL. This last group included the patients who had absence of a convenient amount of bone in donor sites. Each patient received from one to six graft blocks, totalling to 12 ATs and 17 ALs. Seven months after grafting procedures, biopsies of the grafts were made using 2-mm internal diameter trephine burs, and processed for histological analysis. One biopsy was retrieved from each patient. RESULTS: Clinically, all grafts were found to be firm in consistency and well-incorporated to the receptor bed. Histological analysis showed a large amount of necrotic bone surrounded by few spots of new-formed bone in the AL group, suggesting low rate of graft remodeling. In the AT group, an advanced stage of bone remodeling was seen. CONCLUSIONS: Human fresh-frozen bone block AL showed clinical compatibility for grafting procedures, although associated to slow remodeling process. Further studies are needed to define, at long term, the remodeling process chronology the clinical longitudinal results for fresh-frozen bone AL.

Alveolar bone grafting and reconstruction procedures prior to implant placement.

Before implant placement, adequate bone must be present; this is a fundamental step in treatment planning for implants. Understanding the basics of bone grafting and reconstruction techniques is critical for successful implant placement. Alveolar bone grafting can be very intimidating when first attempted. With careful instruction, education, and practice, grafting can be accomplished by many practitioners. Different methods incorporate similar surgical principles while leading to the development of more advanced grafting techniques.

Horizontal bone augmentation: the decision tree.

The emergence of implant dentistry has led to the need for bone augmentation procedures. With the removal of a tooth, there is an inevitable three-dimensional (3D) loss of alveolar bone. More often than not, horizontal bone loss occurs at a faster rate and to a greater extent compared to vertical bone loss. This led to the development of several horizontal bone augmentation techniques, such as guided bone regeneration, ridge expansion, distraction osteogenesis, and block grafts. These proposed augmentation techniques aim to place the implant in an ideal 3D position for successful restorative therapy. The literature has shown that horizontal bone augmentation is fairly predictable if certain criteria are fulfilled. However, with numerous techniques and materials currently available, it is difficult to choose the most suitable treatment modality. A search of the literature available was conducted to validate the decision-making process when planning for a horizontal ridge augmentation procedure. The decision tree proposed in this paper stems from the 3D buccolingual bone width available at the site of implant placement (⋝ 3.5 mm, < 3.5 mm, or 4 to 5 mm). In each dimension, techniques are advised after considering factors such as the tissue thickness, the arch position, and the availability of autogenous bone. The decision tree provides insight on how clinicians can choose the most appropriate and predictable horizontal ridge augmentation procedure to minimize unnecessary complications.

Introduction and overview of bone grafting.

Implants are becoming the standard of care for the replacement of missing teeth; therefore, an in-depth understanding of bone grafting and bone healing is essential for the modern practitioner. We provide an overview of basic bone biology and graft classifications that are frequently used in these procedures. In it, we present the three different properties of bone grafting materials, including osteoinduction, osteogenesis and osteoconduction. And we describe different types of bone grafting materials, including natural and artificial bone sources.

Principles of bone grafting.

This article reviews the principles of bone healing and bone grafting. There are many different ways to reach the same goal when bone grafting procedures are performed. With all of the available methods and materials, a clear understanding of these basic principles will assist in the selection of a technique for each individual patient.

Horizontal ridge augmentation utilizing a composite graft of demineralized freeze-dried allograft, mineralized cortical cancellous chips, and a biologically degradable thermoplastic carrier combined with a resorbable membrane: a retrospective evaluation of 73 consecutively treated cases from private practices.

Ridge deficiency is an unfortunate obstacle in the field of implant dentistry. Many techniques are available to rebuild the deficient ridge. Some of these techniques are associated with significant morbidity and often require a second surgical site. With the advent of guided bone regeneration (GBR), one may now graft the deficient ridge with decreased morbidity and without a second surgical site. The purpose of this retrospective consecutive case series from 5 private practices is to report on the outcomes of a composite material of demineralized freeze-dried allograft, mineralized cortical cancellous chips, and a biologically degradable thermoplastic carrier (Regenaform RT) when combined with a resorbable membrane for GBR of lateral ridge defects in human patients. The specific aim was to quantify clinical results through direct measurement. Data were obtained from 73 consecutively treated lateral ridge augmentations performed on 67 partial and/or completely edentate patients. Clinical data (presurgical ridge width, ridge width at implant placement, and bone density at implant placement) were obtained retrospectively from 5 private practices via an exhaustive retrospective chart review, which was pooled and averaged for analysis. The average gain in horizontal ridge width was 3.5 mm (range, 3-6 mm). The density of the bone was noted to be type 2 to 3, with type 3 being the predominant finding. This retrospective case series from 5 clinical private practices suggests that the use of a composite material of demineralized freeze-dried allograft, mineralized cortical cancellous chips, and a biologically degradable thermoplastic carrier, when covered by a resorbable collagen membrane for GBR, is an effective means of horizontal ridge augmentation.

An immunolocalization study of tissue inhibitors of metalloproteinase-1 of bone graft healing on parietal bone.

This immunolocalization study was performed to investigate the temporal and spatial expression of tissue inhibitors of metalloproteinase (TIMP) 1 within endochondral and intramembranous bone grafts during the early stages of healing, in the hope of gaining a better understanding of the mechanisms of bone graft healing, which could influence the choice of bone graft used. Twenty-seven adult New Zealand White rabbits were used as the experimental model. Autogenous bone grafts taken from the cranial bone (intramembranous in origin) and the femur (endochondral in origin) were grafted into skull defects created on either side of the parietal suture. Rabbits were killed on days 1 to 9 postgrafting, and the bone graft alone was harvested for immunolocalization of TIMP-1. In endochondral bone grafts, TIMP-1 was expressed on days 1 to 3, followed by a period of absence until days 8 and 9. Intramembranous bone grafts did not express TIMP-1 until days 6 to 9. The timing and location of TIMP-1 expression coincided with osteogenesis, which indicates a role for TIMP-1 in preserving newly formed bone during the initial stages of graft healing. The differential temporal expression of TIMP-1 in endochondral and intramembranous bone grafts suggests that bone graft type plays an important role in influencing the healing process mediated by the host tissues. The earlier expression of TIMP-1 in endochondral bone grafts could be the reason for delayed vascularization of defects containing these grafts, whereas the delayed expression of TIMP-1 in intramembranous bone grafts could allow earlier vascularization of the intramembranous bone grafts.

Orthopedic devices; reclassification of the intervertebral body fusion device. Final rule.

The Food and Drug Administration (FDA) is reclassifying intervertebral body fusion devices that contain bone grafting material, from class III (premarket approval) into class II (special controls), and retain those that contain any therapeutic biologic (e.g., bone morphogenic protein) in class III. Elsewhere in this issue of the Federal Register, FDA is announcing the availability of a guidance document that will serve as the special control for this device. This reclassification is based upon on the recommendation of the Orthopaedic and Rehabilitation Devices Panel (the Panel).

[Bone transplant]. / Trasplante óseo.

We describe the methodology of the Bone and Soft Tissue Bank, from extraction and storage until use. Since the year 1986, with the creation of the Bone Bank in the University Clinic of Navarra, more than 3,000 grafts have been used for very different types of surgery. Bone grafts can be classified into cortical and spongy; the former are principally used in surgery to save tumour patients, in large post-traumatic reconstructions and in replacement surgery where there are massive bone defects and a structural support is required. The spongy grafts are the most used due to their numerous indications; they are especially useful in filling cavities that require a significant quantity of graft when the autograft is insufficient, or as a complement. They are also of special help in treating fractures when there is bone loss and in the treatment of delays in consolidation and pseudoarthrosis in little vascularized and atrophic zones. They are also used in prosthetic surgery against the presence of cavity type defects. Allografts of soft tissues are specially recognised in multiple ligament injuries that require reconstructions. Nowadays, the most utilised are those employed in surgery of the anterior cruciate ligament although they can be used for filling any ligament or tendon defect. The principal difficulties of the cortical allografts are in the consolidation of the ends with the bone itself and in tumour surgery, given that these are patients immunodepressed by the treatment, the incidence of infection is increased with respect to spongy grafts and soft tissues, which is irrelevant. In short, the increasingly widespread use of allografts is an essential therapeutic weapon in orthopaedic surgery and traumatology. It must be used by expert hands.

Matrix metalloproteinase-9 regulates graft bone resorption.

OBJECTIVE: To explore the relationship between bone resorption and matrix metalloproteinase-9 (MMP-9) expression in autogenous and allogenic bone grafts. MATERIALS AND METHODS: A total of 18 critical-size (10 x 15 mm) defects were created in rabbit mandibles bilaterally. Three groups of six defects each were grafted with autogenous endochondral (EC) bone, autogenous intramembranous (IM) bone, and allogenic IM bone. Three months later, the defects were retrieved for quantitative analysis on the basis of histology, immunohistochemistry, and in situ hybridization. RESULTS: A close relationship existed between MMP-9 expression and graft bone resorption. The parallel between MMP-9 expression and graft bone resorption suggested that bone resorption was accomplished in part by increased MMP-9 production evident in preosteoclasts and osteoclasts. CONCLUSIONS: MMP-9 plays an important role in graft bone resorption. Autogenous EC bone grafts express higher levels of MMP-9 leading to more resorption than autogenous or allogenic IM bone grafts.