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   Table of Contents - Current issue
September-December 2019
Volume 2 | Issue 3
Page Nos. 41-61

Online since Friday, December 20, 2019

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The role of centrifugation process in the preparation of therapeutic blood concentrates: Standardization of the protocols to improve reproducibility p. 41
Shahram Ghanaati, Carlos Fernando Mourão, Elisabeth H Adam, Robert Sader, Homayoun H Zadeh, Sarah Al-Maawi
Investigations of endogenous blood-derived growth factors have increased in the past two decades. The initial protocols for blood concentrates, such as platelet-rich-plasma, utilized anticoagulants followed by bovine thrombin to catalyze fibrin polymerization. Subsequently, platelet-rich-fibrin (PRF) protocol was developed to eliminate anticoagulants and thrombin. The PRF production was described in a vertical rotor centrifuge with an angle of ~33°. Many commercial enterprises have attempted to replicate this protocol with a multitude of different centrifuges. These attempts have utilized revolutions per minute (RPM) to develop their protocol to generate PRF. However, RPM is a variable parameter, as it depends on the design and radius of the centrifuge. The separation of blood components is highly dependent on the relative centrifugal force (RCF) generated, which is based on the applied centrifugal force, expressed as multiples of earth's gravitation (g) field. RCF is a function of the acceleration due to the gravity of the earth, g = 9.81 m/s2 RCF, not RPM, is the key factor for the sedimentation of the cells and proteins within blood concentrates. RCF is determined using the maximum centrifuge radius for calculation. The initial PRF was generated by applying an RCF of 700 ×g. Accordingly, so far, a large number of studies existing about PRF are not comparable, as they were technically prepared with different RCFs. In addition, due to the nonstandardized measurement methods, in some published studies, incorrect RCF values are published as the authors did not know how to calculate the RCF correctly. This is the case for a widespread blood concentrate called leukocyte-PRF, which is commercially available. Recently, we introduced the low-speed centrifugation concept (LSCC) for the production for solid and liquid PRF matrices. This concept is based on the above-mentioned initial PRF protocols, which represents a relatively high RCF. It shows that a systematic reduction of 700 ×g to 44 ×g can significantly increase the cells and growth factors within the same blood concentrates. The LSCC concept was established initially for a fixed rotor centrifuge with a radius of ~110 mm. The present narrative review highlights the necessity of standardization in the generation of blood concentrates, which utilizes RCF, rather than commercial protocols.
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Autologous tooth graft for maxillary sinus augmentation: A multicenter clinical study p. 45
Elio Minetti, Andrea Palermo, Marcello Contessi, Ugo Gambardella, Johannes H Schmitz, Edoardo Giacometti, Martin Celko, Paolo Trisi
Aim: The aim of this pilot study was to assess the performance of autologous tooth matrix, used as a graft material for maxillary sinus augmentation, after at least 1-year of follow-up. Settings and Design: The patients included in this prospective case series study were treated in four clinical centers using standardized clinical procedures. Materials and Methods: Patients with atrophic posterior maxilla in need of sinus augmentation before rehabilitation with implant-supported prostheses, and with compromised teeth to be extracted, were included. The extracted tooth was cleaned and processed by a recently introduced automated device, which allows fragmentation and partial demineralization of the tooth matrix, and used as a graft material for sinus augmentation. A covering membrane was used to protect the graft. Implants were placed after 6 months of healing. Five bone biopsies of the grafted sites were taken at the time of implant surgery, for histological analysis. Implants were followed for at least 1 year after placement. Cone-beam computed tomography and/or standardized periapical radiographs were used to assess the ridge height before and after grafting, up to 1-year postimplantation. Statistical Analysis: Descriptive statistics were used to synthesize the results, using mean values and standard deviations. Results: Twenty-three patients (9 males, mean age at surgery 57.1 ± 9.4 years) were treated and 40 implants were placed in grafted sites. Residual ridge height was 5.22 ± 2.04 mm and increased to 14.72 ± 2.83 mm after grafting. One implant failed during healing phase. Cumulative implant survival rate was 97.5% after 19.1 ± 8.0 months of follow-up (range 12.3–44.1 months). After 6 months of healing, the graft height appeared stable. No signs of sinus infection were present. The histologic analysis revealed neither inflammatory nor infective reaction against tooth graft. Granules appeared surrounded by newly formed bone and partially resorbed, indicating ongoing remodeling. Conclusion: Autologous human tooth matrix can be successfully used as graft material in sinus augmentation procedure.
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Platelet-rich fibrin for the management of an unusual case of gingival peripheral odontogenic myxoma p. 52
Deepak Sharma, Anchana Gulati, Pravesh Jhingta, Brijesh Kumar
Odontogenic myxoma (OM) is a rare, benign neoplasm and is often located in the maxillofacial region. Clinical, radiological, and histopathological features should be considered when making a diagnosis. Several of these characteristics overlap with those of other benign and some malignant tumors. Soft-tissue localization that is classified as a peripheral myxoma is rarely seen than central localization. Peripheral myxoma is slowly growing and less aggressive compared to central myxoma and has a low recurrence rate. The probability that small peripheral OMs (POMs) are interpreted as edematous irritation fibromas may contribute to the small number of POMs recorded in literature. The treatment plan should consider the age and sex of the patient and the site and size of the lesion. In this report, the application of platelet-rich fibrin in the management of an unusual case of POM located on the gingiva in the posterior maxillary gingival region is presented.
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Tooth transformer®: A new method to prepare autologous tooth grafts – Histologic and histomorphometric analyses of 11 consecutive clinical cases p. 56
Elio Minetti, Andrea Palermo, Paolo Trisi, Silvio Luigi Taschieri
Introduction: Human dentin matrix could be successfully used for bone grafting procedures. It was well accepted that dentin grafts can induce osteoblast proliferation. An innovative preparation method, using the dedicated automated device Tooth Transformer®, which can transform autologous teeth in suitable grafting material, has been recently introduced. The aim of the present article is to analyze the histologic outcomes in 11 consecutive human cases, in which autologous tooth graft materials, starting from the whole tooth of the patient, were used for bone regeneration. Results: The bone defects were completely filled by newly formed tissue after 4 months of healing. Histologic analysis revealed no inflammatory or infective reactions against the tooth graft. Tooth granules were surrounded by newly formed bone. Some tooth granules were incorporated in the bony trabeculae, and they appeared partially resorbed. This fact testified that tooth grafts underwent remodeling processes just like the native bone. Discussion: Results from the present histologic case series analysis revealed that tooth graft appeared well integrated in the regenerative tissue without any inflammatory or infective reaction. The tooth of the patient may be used as an autologous regenerative material, avoiding any foreign graft material.
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