ENAMEL MATRIX PROTEINS ENHANCE OSTEOBLAST SPREADING, PROLIFERATION AND DIFFERENTIATION ON TITANIUM SURFACES

Modifications of implant surface topography and chemistry have proven a means to enhance osseointegration, a process that ensures the stability of bone-contacting devices including titanium dental implants. Enamel matrix derivative (EMD) extracted from developing porcine teeth, has been shown to promote regeneration of bone. The aim of the present study was to evaluate the effect of EMD on the attachment, proliferation and differentiation of osteoblasts on titanium surfaces in vitro. Pickled (smooth) and SLA (Sand-blasted with Large grit followed by Acid etching) titanium discs were coated with EMD or left uncoated. Primary rat calvarial osteoblasts were cultured on each surface 1 hour to 4 weeks. EMD significantly increased cell spreading and proliferation at time points ranging from 3 to 7 days on both topographies. Alkaline phosphatase activity was significantly increased on EMD-coated titanium compared with titanium alone. Moreover, there was a 4-fold increase in levels of mRNA encoding bone sialoprotein and osteocalcin in osteoblasts cultured on EMD-coated titanium surfaces compared with uncoated surfaces. We conclude that coating of titanium with EMD enhances the proliferation and differentiation of osteoblasts irrespective of the titanium substratum topography. Therefore, EMD may increase the speed and quality of osseointegration around bone contacting implants in vivo

Optimized bone grafting.

Bone grafting is routinely performed in periodontology and oral surgery to fill bone voids. While autogenous bone is considered the gold standard because of its regenerative properties, allografts and xenografts have more commonly been utilized owing to their availability as well as their differential regenerative/biomechanical properties. In particular, xenografts are sintered at high temperatures, which allows for their slower degradation and resorption rates and/or nonresorbable features. As a result, clinicians have combined xenografts with other classes of bone grafts (most notably allografts and autografts in various ratios) for procedures requiring better long-term stability, such as contour grafting, sinus elevation procedures, and vertical bone augmentations. This review addresses the regenerative properties of each class of bone grafts and then highlights the importance of understanding each of their biomechanical and regenerative properties for clinical applications, including extraction site management, contour augmentation, sinus grafting, and horizontal and vertical augmentation procedures. Thereafter, an introduction toward the novel production of nonresorbable bone allografts (NRBAs) via high-temperature sintering is presented. These NRBAs not only pose the advantage of being more biocompatible than xenografts owing to their origin (human vs. animal bone) but also display nonresorbable properties similar to those of xenografts. Thus, while packaging allografts with xenografts in premixtures specific to various clinical indications has never been permitted owing to cross-species contamination and FDA/CE requirements, the discovery and production of NRBAs allows premixing with standard allografts in various ratios without regulatory restrictions. Therefore, premixtures of allografts with NRBAs can be produced in various ratios for specific indications (e.g., a 1:1 ratio similar to an allograft/xenograft mixture for sinus grafting) without the need for purchasing separate classes of bone grafts. This optimized form of bone grafting could theoretically provide clinicians more precise ratios without the need to purchase separate bone grafts. This review highlights the future potential for simplified and optimized bone grafting in periodontology and implant dentistry

Understanding exosomes: Part 1-Characterization, quantification and isolation techniques.

Exosomes are the smallest subset of extracellular signaling vesicles secreted by most cells with a diameter in the range of 30-150 nm. Their use has gained great momentum recently due to their ability to be utilized as diagnostic tools with a vast array of therapeutic applications. Over 5000 publications are currently being published yearly on this topic, and this number is only expected to dramatically increase as novel therapeutic strategies continue to be investigated. This review article first focuses on understanding exosomes, including their cellular origin, biogenesis, function, and characterization. Thereafter, overviews of the quantification methods and isolation techniques are given with discussion over their potential use as novel therapeutics in regenerative medicine

Autolougous platelet concentrates in esthetic medicine.

This narrative review summarizes current knowledge on the use of autologous platelet concentrates (APCs) in esthetic medicine, with the goal of providing clinicians with reliable information for clinical practice. APCs contain platelets that release various growth factors with potential applications in facial and dermatologic treatments. This review examines several facial esthetic applications of APCs, including acne scarring, skin rejuvenation, melasma, vitiligo, stretchmarks, peri-orbital rejuvenation, peri-oral rejuvenation, hair regeneration and the volumizing effects of APC gels. A systematic review of literature databases (PubMed/MEDLINE) was conducted up to October 2023 to identify randomized controlled trials (RCTs) in the English language on APCs for facial rejuvenation and dermatology. A total of 96 articles were selected including those on platelet rich plasma (PRP), plasma-rich in growth factors (PRGF), and platelet-rich fibrin (PRF). Clinical recommendations gained from the reviews are provided. In summary, the use of APCs in facial esthetics is a promising yet relatively recent treatment approach. Overall, the majority of studies have focused on the use of PRP with positive outcomes. Only few studies have compared PRP versus PRF with all demonstrating superior outcomes using PRF. The existing studies have limitations including small sample sizes and lack of standardized assessment criteria. Future research should utilize well-designed RCTs, incorporating appropriate controls, such as split-face comparisons, and standardized protocols for APC usage, including optimal number of sessions, interval between sessions, and objective improvement scores. Nevertheless, the most recent formulations of platelet concentrates offer clinicians an ability to improve various clinical parameters and esthetic concerns

From service provision to function based performance - perspectives on public health systems from the USA and Israel

If public health agencies are to fulfill their overall mission, they need to have defined measurable targets and should structure services to reach these targets, rather than offer a combination of ill-targeted programs. In order to do this, it is essential that there be a clear definition of what public health should do- a definition that does not ebb and flow based upon the prevailing political winds, but rather is based upon professional standards and measurements. The establishment of the Essential Public Health Services framework in the U.S.A. was a major move in that direction, and the model, or revisions of the model, have been adopted beyond the borders of the U.S. This article reviews the U.S. public health system, the needs and processes which brought about the development of the 10 Essential Public Health Services (EPHS), and historical and contemporary applications of the model. It highlights the value of establishing a common delineation of public health activities such as those contained in the EPHS, and explores the validity of using the same process in other countries through a discussion of the development in Israel of a similar model, the 10 Public Health Essential Functions (PHEF), that describes the activities of Israel’s public health system. The use of the same process and framework to develop similar yet distinct frameworks suggests that the process has wide applicability, and may be beneficial to any public health system. Once a model is developed, it can be used to measure public health performance and improve the quality of services delivered through the development of standards and measures based upon the model, which could, ultimately, improve the health of the communities that depend upon public health agencies to protect their well-being

From service provision to function based performance - perspectives on public health systems from the USA and Israel

If public health agencies are to fulfill their overall mission, they need to have defined measurable targets and should structure services to reach these targets, rather than offer a combination of ill-targeted programs. In order to do this, it is essential that there be a clear definition of what public health should do- a definition that does not ebb and flow based upon the prevailing political winds, but rather is based upon professional standards and measurements. The establishment of the Essential Public Health Services framework in the U.S.A. was a major move in that direction, and the model, or revisions of the model, have been adopted beyond the borders of the U.S. This article reviews the U.S. public health system, the needs and processes which brought about the development of the 10 Essential Public Health Services (EPHS), and historical and contemporary applications of the model. It highlights the value of establishing a common delineation of public health activities such as those contained in the EPHS, and explores the validity of using the same process in other countries through a discussion of the development in Israel of a similar model, the 10 Public Health Essential Functions (PHEF), that describes the activities of Israel’s public health system. The use of the same process and framework to develop similar yet distinct frameworks suggests that the process has wide applicability, and may be beneficial to any public health system. Once a model is developed, it can be used to measure public health performance and improve the quality of services delivered through the development of standards and measures based upon the model, which could, ultimately, improve the health of the communities that depend upon public health agencies to protect their well-being

Blood Clots versus PRF: Activating TGF-β Signaling and Inhibiting Inflammation In Vitro.

The preparation of platelet-rich fibrin (PRF) requires blood centrifugation to separate the yellow plasma from the red erythrocyte fraction. PRF membranes prepared from coagulated yellow plasma are then transferred to the defect sites to support tissue regeneration. During natural wound healing, however, it is the unfractionated blood clot (UBC) that fills the defect site. It is unclear whether centrifugation is necessary to prepare a blood-derived matrix that supports tissue regeneration. The aim of the present study was to compare lysates prepared from PRF and UBC based on bioassays and degradation of the respective membranes. We report here that lysates prepared from PRF and UBC membranes similarly activate TGF-β signaling, as indicated by the expression of interleukin 11 (IL-11), NADPH oxidase 4 (NOX-4) and proteoglycan 4 (PRG4) in gingival fibroblasts. Consistently, PRF and UBC lysates stimulated the phosphorylation and nuclear translocation of Smad3 in gingival fibroblasts. We further observed that PRF and UBC lysates have comparable anti-inflammatory activity, as shown by the reduction in lipopolysaccharide (LPS)-induced IL-6, inducible nitric oxidase synthase (iNOS) and cyclooxygenase 2 (COX-2) expression in RAW264.7 cells. Moreover, inflammation induced by Poly (1:C) HMW and FSL-1, which are agonists of Toll-like receptor (TLR) 3 and 2/6, respectively, was reduced by both PRF and UBC. PRF and UBC lysates reduced the nuclear translocation of p65 in LPS-induced RAW264.7 cells. In contrast to the similar activity observed in the bioassays, UBC membranes lack the structural integrity of PRF membranes, as indicated by the rapid and spontaneous disintegration of UBC membranes. We show here that the lysates prepared from PRF and UBC possess robust TGF-β and anti-inflammatory activity. However, visual inspection of the PRF and UBC membranes confirmed the negative impact of erythrocytes on the structural integrity of membranes prepared from whole blood. The data from the present study suggest that although both UBC and PRF have potent TGF-β and anti-inflammatory activity, UBC does not have the strength properties required to be used clinically to prepare applicable membranes. Thus, centrifugation is necessary to generate durable and clinically applicable blood-derived membranes

Fibrinogen Concentrations in Liquid PRF Using Various Centrifugation Protocols.

Liquid platelet-rich fibrin (PRF) is produced by fractionation of blood without additives that initiate coagulation. Even though liquid PRF is frequently utilized as a natural source of fibrinogen to prepare sticky bone, the concentration of fibrinogen and the overall amount of "clottable PRF" components have not been evaluated. To this aim, we prepared liquid PRF at 300, 700, and 2000 relative centrifugal force (RCF), for 8 min and quantified the fibrinogen levels by immunoassay. We report here that, independent of the RCF, the fibrinogen concentration is higher in the platelet-poor plasma (PPP) compared to the buffy coat (BC) fraction of liquid PRF and further decreases in the remaining red fraction. We then determined the weight of the clotted PRF fractions before and after removing the serum. The PPP and BC fractions consist of 10.2% and 25.3% clottable matrix suggesting that more than half of the weight of clottable BC is caused by cellular components. Our data provide insights into the distribution of fibrinogen in the different fractions of liquid PRF. These findings suggest that PPP is the main source of clottable fibrinogen, while the BC is more a cell source when it comes to the preparation of sticky bone

Osteoblast proliferation and differentiation on a barrier membrane in combination with BMP2 and TGFβ1

Objectives: Bioresorbable collagen membranes are routinely utilized in guided bone regeneration to selectively direct the growth and repopulation of bone cells in areas of insufficient volume. However, the exact nature by which alveolar osteoblasts react to barrier membranes as well as the effects following the addition of growth factors to the membranes are still poorly understood. The objective of the present study was therefore to investigate the effect of a bioresorbable collagen membrane soak-loaded in growth factors bone morphogenetic protein 2 (BMP2) or transforming growth factor β1 (TGFβ1) on osteoblast adhesion, proliferation, and differentiation. Material and methods: Prior to experimental seeding, membranes were soaked in either BMP2 or TGFβ1 at a concentration of 10ng/ml for 5min. Results: Human osteoblasts adhered to all soak-loaded membranes as assessed by scanning electron microscopy. Growth factors BMP2 and TGFβ1 increased osteoblast proliferation at 3 or 5days post-seeding when compared to control collagen membranes. Analysis of real-time PCR revealed that administration of BMP2 increased osteoblast differentiation markers such as osterix, collagen I, and osteocalcin. BMP2 also increased mineralization of primary osteoblasts as demonstrated by alizarin red staining when compared to control and TGFβ1 soak-loaded membranes. Conclusion: The combination of a collagen barrier membrane with growth factors TGFβ1 and BMP2 significantly influenced adhesion, proliferation, and differentiation of primary human osteoblasts. Clinical relevance: The described in vitro effects following the combination of collagen barrier membranes with growth factors TGFβ1 and BMP2 provide further biologic support for the clinical application of this treatment strategy in guided bone regeneration procedure

Gene array of primary human osteoblasts exposed to enamel matrix derivative in combination with a natural bone mineral

Objectives: The application of an enamel matrix derivative (EMD) for regenerative periodontal surgery has been shown to promote formation of new cementum, periodontal ligament, and alveolar bone. In intrabony defects with a complicated anatomy, the combination of EMD with various bone grafting materials has resulted in additional clinical improvements, but the initial cellular response of osteoblasts coming in contact with these particles have not yet been fully elucidated. The objective of the present study was to evaluate the in vitro effects of EMD combined with a natural bone mineral (NBM) on a wide variety of genes, cytokines, and transcription factors and extracellular matrix proteins on primary human osteoblasts. Material and methods: Primary human osteoblasts were seeded on NBM particles pre-coated with versus without EMD and analyzed for gene differences using a human osteogenesis gene super-array (Applied Biosystems). Osteoblast-related genes include those transcribed during bone mineralization, ossification, bone metabolism, cell growth and differentiation, as well as gene products representing extracellular matrix molecules, transcription factors, and cell adhesion molecules. Results: EMD promoted gene expression of various osteoblast differentiation markers including a number of collagen types and isoforms, SMAD intracellular proteins, osteopontin, cadherin, alkaline phosphatase, and bone sialoprotein. EMD also upregulated a variety of growth factors including bone morphogenetic proteins, vascular endothelial growth factors, insulin-like growth factor, transforming growth factor, and their associated receptor proteins. Conclusion: The results from the present study demonstrate that EMD is capable of activating a wide variety of genes, growth factors, and cytokines when pre-coated onto NBM particles. Clinical relevance: The described in vitro effects of EMD on human primary osteoblasts provide further biologic support for the clinical application of a combination of EMD with NBM particles in periodontal and oral regenerative surger