Tomographic, Histological, and Immunohistochemical Evidences on the Use of N-Butyl-2-Cyanoacrilate for Onlay Graft Fixation in Rabbits

Background: The bone tissue responses to Cyanoacrylate have been described in the literature, but none used N-butyl-2-cyanoacrilate (NB-Cn) for bone graft fixation. Purpose: The aims of the study were: (a) to analyze the bone grafts volume maintenance fixed either with NB-Cn or titanium screw; (b) to assess the incorporation of onlay grafts on perforated recipient bed; and (c) the differences of expression level of tartrate-resistant acid phosphatase (TRAP) protein involved in bone resorption. Materials and Methods: Eighteen New Zealand White rabbits were submitted to calvaria onlay grafting on both sides of the mandible. On one side, the graft was fixed with NB-Cn, while on the other hand the bone graft was secured with an osteosynthesis screw. The computed tomography (CT) was performed just after surgery and at animals sacrifice, after 1 (n=9) and 6weeks (n=9), in order to estimate the bone grafts volume along the experiments. Histological sections of the grafted areas were prepared to evaluate the healing of bone grafts and to assess the expression of TRAP protein. Results: The CT scan showed better volume maintenance of bone grafts fixed with NB-Cn (p≤0.05) compared with those fixed with screws, in both experimental times (analysis of variance). The immunohistochemical evaluation showed that the TRAP expression in a 6-week period was significantly higher compared with the 1-week period, without showing significant difference between the groups (Wilcoxon and Mann-Whitney). Histological analysis revealed that the NB-Cn caused periosteum damage, but provided bone graft stabilization and incorporation similar to the control group. Conclusion: The perforation provided by screw insertion into the graft during fixation may have triggered early revascularization and remodeling to render increased volume loss compared with the experimental group. These results indicate that the NB-Cn possesses equivalent properties to titanium screw to be used as bone fixation material in osteosynthesis. © 2010 Wiley Periodicals, Inc.

Mechanical Property Assessment of Bone Healing around a Titanium-Zirconium Alloy Dental Implant

Background: It has been reported that titanium-zirconium alloy with 13-17% zirconium (TiZr1317) implants show higher biomechanical stability and bone area percentage relative to commercially pure titanium (cpTi) grade 4 fixtures. Purpose: This study aimed to determine whether the higher stability for TiZr1317 implants is associated with higher mechanical properties of remodeling bone in the areas around the implants. Materials and Methods: This study utilized 36 implants (n=18: TiZr1317, n=18: cpTi), which were placed in the healed ridges of the mandibular premolar and first molar of 12 mini pigs (n=3 implants/animal). After 4 weeks in vivo, the samples were retrieved, and resin-embedded histologic sections of approximately 100μm in thickness were prepared. In order to determine the nanomechanical properties, nanoindentation (n=30 tests/specimen) was performed on the bone tissue of the sections under wet conditions with maximum load of 300μN (loading rate: 60μN/s). Results: The mean (±standard deviation) elastic modulus (E) and hardness (H) for the TiZr1317 group were 2.73±0.50GPa and 0.116±0.017GPa, respectively. For the cpTi group, values were 2.68±0.51GPa and 0.110±0.017GPa for E and H, respectively. Although slightly higher mechanical properties values were observed for the TiZr1317 implants relative to the cpTi for both elastic modulus and hardness, these differences were not significant (E=p>0.75; H=p>0.59). Conclusions: The titanium-zirconium alloy used in this study presented similar degrees of nanomechanical properties to that of the cpTi implants. © 2013 Wiley Periodicals, Inc.

Platelet lysate 3D scaffold supports mesenchymal stem cell chondrogenesis: An improved approach in cartilage tissue engineering

Articular lesions are still a major challenge in orthopedics because of cartilage's poor healing properties. A major improvement in therapeutics was the development of autologous chondrocytes implantation (ACI), a biotechnology-derived technique that delivers healthy autologous chondrocytes after in vitro expansion. To obtain cartilage-like tissue, 3D scaffolds are essential to maintain chondrocyte differentiated status. Currently, bioactive 3D scaffolds are promising as they can deliver growth factors, cytokines, and hormones to the cells, giving them a boost to attach, proliferate, induce protein synthesis, and differentiate. Using mesenchymal stem cells (MSCs) differentiated into chondrocytes, one can avoid cartilage harvesting. Thus, we investigated the potential use of a platelet-lysate-based 3D bioactive scaffold to support chondrogenic differentiation and maintenance of MSCs. The MSCs from adult rabbit bone marrow (n=5) were cultivated and characterized using three antibodies by flow cytometry. MSCs (1×105) were than encapsulated inside 60μl of a rabbit platelet-lysate clot scaffold and maintained in Dulbecco's Modified Eagle Medium Nutrient Mixture F-12 supplemented with chondrogenic inductors. After 21 days, the MSCs-seeded scaffolds were processed for histological analysis and stained with toluidine blue. This scaffold was able to maintain round-shaped cells, typical chondrocyte metachromatic extracellular matrix deposition, and isogenous group formation. Cells accumulated inside lacunae and cytoplasm lipid droplets were other observed typical chondrocyte features. In conclusion, the usage of a platelet-lysate bioactive scaffold, associated with a suitable chondrogenic culture medium, supports MSCs chondrogenesis. As such, it offers an alternative tool for cartilage engineering research and ACI. © 2013 Informa UK Ltd.

Incomplete mandibular fracture after lateralization of the inferior alveolar nerve for implant placement

PURPOSE: The present case describes an inferior alveolar nerve lateralization for implant placement that caused mandible fracture a few days after surgery. CLINICAL REPORT: In this case, a 56-year-old female patient who had a severely atrophied jaw and showing bone height less than 7 mm from the bone crest and the mandibular canal was submitted to surgery lateralization of the inferior alveolar conducted with piezzo. Even with all postoperative care, the patient suffered an incomplete fracture of the mandible a few days after lateralization of the inferior alveolar nerve for implant placement. The patient was treated with soft diet and medications for pain and antibiotics, besides removing the implant associated with the fracture. CONCLUSION: It is suggested that this procedure may be conducted in 2 operative periods: firstly, the lateralization of the inferior alveolar; and secondly, after a period of 3 months, the implant placement in a situation of more bone stability. Copyright © 2013 by Mutaz B. Habal, MD.

Failure of miniplate osteosynthesis for the management of atrophic mandibular fracture

Fractures of the severely atrophic (<10 mm) edentulous mandible are not common, and these fractures with a vertical height of 10 mm or less have long been recognized as being particularly problematic. Although there are advances in the treatment of the atrophic mandibular fracture, the treatment remains controversial. There are some options for treatment planning because of using small miniplates to large reconstruction plates. However, when the fixation method fails, it causes malunion, nonunion, and/or infection, and sometimes it has been associated with large bone defects. The authors describe a clinical report of a failed miniplate fixation for atrophic mandibular fracture management. The authors used a load-bearing reconstruction plate combined with autogenous bone graft from iliac crest for this retreatment. The authors show a follow-up of 6 months, with union of the fracture line and no complication postoperatively. © 2013 by Mutaz B. Habal, MD.

Management of pure medial orbital wall fracture with autogenous bone graft

The orbit is an irregular conical cavity formed from 7 bones including the frontal, sphenoid, zygomatic, maxillary, ethmoid, lacrimal, and palatine bones. Fractures of the internal orbit can cause a number of problems, including diplopia, ocular muscle entrapment, and enophthalmos. Although muscle entrapment is relatively rare, diplopia and enophthalmos are relatively common sequelae of internal orbital fractures. Medial orbital wall fracture is relatively uncommon and represents a challenge for its anatomical reconstruction. In this context, autogenous bone graft has been the criterion standard to provide framework for facial skeleton and orbital walls. Therefore, it is possible to harvest grafts of varying size and contour, and the operation is performed through the bicoronal incision, which is the usual approach to major orbital reconstruction. Thus, this article aimed to describe a patient with a pure medial orbital wall fracture, and it was causing diplopia and enophthalmos. The orbital fracture was treated using autogenous bone graft from calvarial bone. The authors show a follow-up of 12 months, with facial symmetry and without diplopia and enophthalmos. In addition, a computed tomography scan shows excellent bone healing at the anterior and posterior parts of the medial orbital wall reconstruction. Copyright © 2013 by Mutaz B. Habal, MD.

Using the bottom-up and outside-in sequence for panfacial fracture management: Does it provide a clinical significance?

Panfacial fractures usually refer to simultaneous facial fractures, which affect the upper, middle, and lower thirds of the face. The management of panfacial fracture is complex because of the lack of reliable landmarks. Literature has shown many approaches for management of panfacial fractures. Every segment of bone has a precise function in the repair. Therefore, the bottom-up and outside-in sequence is the most widely used approach in the management of panfacial fractures. These facial fractures present remarkable challenges for both experienced and inexperienced surgeons. This article aimed to report a case of a panfacial fracture (mandibular condylar and symphysis fractures associated with an atypical Le Fort III fracture) in a 48-year-old man. The patient was successfully treated using bottom-up and outside-in sequence by accessing all facial injuries. Postoperatively, radiograph examination revealed good reduction and fixation of titanium plates, and physical examination revealed good functional and esthetic outcomes. Copyright © 2013 by Mutaz B. Habal, MD.

Avaliação do seio maxilar após fratura do complexo zigomático-maxilar tratado com fixação interna rígida em dois pontos: estudo radiográfico em humanos

Pós-graduação em Odontologia - FOA

Avaliação in vitro do uso de uma miniplaca convencional e locking, de 4 e 7 furos, para tratamento das fraturas de ângulo mandibular

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Osteossíntese minimamente invasiva com placa bloqueada nas fraturas de tíbia em cães

Pós-graduação em Cirurgia Veterinária - FCAV

Avaliação do comportamento mecânico de três diferentes tipos de osteossíntese em fratura de côndilo mandibular: análise por elementos finitos 3D

Pós-graduação em Odontologia - FOAR

Block Bone Graft Fixation ( Onlay): A Modification of the Surgical Technique

Several reconstructive methods of the alveolar ridge have been reported to make possible future rehabilitations with implants. Many of these methods come from studies done in animals, mainly rats. With this clinical practice based on scientific evidence, any experimental procedure that can be undertaken in real life is fundamental. Thus, any research that emulates as closely as possible those techniques used in humans are important. This study describes the modification of the technique for block bone graft fixation (onlay) in rats using the lag screw-type technique, normally used in clinical procedures for grafts in humans. The conclusion was that the execution of the described procedures minimizes interference of blood flow in the area because of the maintenance of the muscle insertion in the buckle aspect of the most anterior region of the mandible, providing better stability to the graft and better contact interface of the graft and receptor bed.

Finite element evaluation of three methods of stable fixation of condyle base fractures

The surgical treatment of mandibular condyle fractures currently offers several possibilities for stable internal fixation. In this study, a finite element model evaluation was performed of three different methods for osteosynthesis of low subcondylar fractures: (1) two four-hole straight plates, (2) one seven-hole lambda plate, and (3) one four-hole trapezoidal plate. The finite element model evaluation considered a load applied to the first molar on the contralateral side to the fracture. Results showed that, although the three methods are capable of withstanding functional loading, the lambda plate displayed a more homogeneous stress distribution for both osteosynthesis material and bone and may be a better method when single-plate fixation is the option.

Position paper from the IBRA Symposium on Surgery of the Head - The 2nd International Symposium for Condylar Fracture Osteosynthesis, Marseille, France 2012

Background: This is a position paper from the 2nd International Bone Research Association (IBRA) Symposium for Condylar Fracture Osteosynthesis 2012 was held at Marseille, succeeding the first congress in Strasbourg, France, in 2007. The goal of this IBRA symposium and this paper was to evaluate current trends and potential changes of treatment strategies for mandibular condylar fractures, which remain controversial over the past decades.Methods: Using a cross-sectional study design, we enrolled the consensus based on the panel of experts and participants in the IBRA Symposium 2012. The outcomes of interest were the panel and electronic votes on management of condylar base, neck and head fractures, and panel votes on endoscopic and paediatric condylar fractures. Appropriate descriptive and univariate statistics were used.Results: The consensus derived from 14 experts and 41 participant surgeons, using 12 case scenarios and 27 statements. The experts and participants had similar decision on the treatment of condylar base, neck and head fractures, as well as similar opinion on complications of condylar fracture osteosynthesis. They had a parallel agreement on using open reduction with internal fixation (ORIF) as treatment of choice for condylar base and neck fractures in adults. Endoscopic approaches should be considered for selected cases, such as condylar base fractures with lateral displacement. There was also a growing tendency to perform ORIF in condylar head fractures. The experts also agreed to treat children (> 12 years old) in the same way as adults and to consider open reduction in severely displaced and dislocated fractures even in younger children. Nevertheless, non-surgical treatment should be the first choice for children <6 years of age. The decision to perform surgery in children was based on factors influencing facial growth, appropriate age for ORIF, and disagreement to use resorbable materials in children.Conclusions: The experts and participating surgeons had comparable opinion on management of condylar fractures and complications of ORIF. Compared to the first Condylar Fracture Symposium 2007 in Strasbourg, ORIF may now be considered as the gold standard for both condylar base and neck fractures with displacement and dislocation. Although ORIF in condylar head fractures in adults and condylar fractures in children with mixed dentition is highly recommended, but this recommendation requires further investigations. (C) 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Biomechanical Study in Polyurethane Mandibles of Different Metal Plates and Internal Fixation Techniques, Employed in Mandibular Angle Fractures

The aim of this study was to perform a physicochemical and morphological characterization and compare the mechanical behavior of an experimental Ti-Mo alloy to the analogous metallic Ti-based fixation system, for mandibular angle fractures. Twenty-eight polyurethane mandibles were uniformly sectioned on the left angle. These were divided into 4 groups: group Eng 1P, one 2.0-mm plate and 4 screws 6 mm long; group Eng 2P, two 2.0-mm plates, the first fixed with 4 screws 6 mm long and the second with 4 screws 12 mm long. The same groups were created for the Ti-15Mo alloy. Each group was subjected to linear vertical loading at the first molar on the plated side in a mechanical testing unit. Means and standard deviations were compared with respect to statistical significance using ANOVA. The chemical composition of the Ti-15Mo alloy was close to the nominal value. The mapping of Mo and Ti showed a homogeneous distribution. SEM of the screw revealed machining debris. For the plates, only the cpTi plate undergoes a surface treatment. The metallographic analysis reveals granular microstructure, from the thermomechanical trials. A statistically significant difference was found (P < 0.05) when the comparison between both internal fixation techniques was performed. The 2P technique showed better mechanical behavior than 1P.