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In the field of biology and medicine, one hears often about stem cells and their potential. The dental implant new surfaces, subjected to specific treatments, perform better and allow for quicker healing times and better clinical performance. The purpose of this study is to evaluate from a biological point of view the interaction and cytotoxicity between stem cells derived from dental pulp (DPSCs) and titanium surfaces. Through the creation of complex cells/implant, this study is aimed at analyzing the cytotoxicity of dental implant surfaces (Myth (Maipek Manufacturer Industrial Care, Naples, Italy)) and the adhesion capacity of cells on them and at considering the essential factors for implant healing such as osteoinduction and vasculogenesis. These parameters are pointed out through histology (3D cell culture), immunofluorescence, proliferation assays, scanning electron microscopy, and PCR investigations. The results of the dental implant surface and its interaction with the DPSCs are encouraging, obtaining results increasing the mineralization of the tissues. The knowledge of this type of interaction, highlighting its chemical and biological features, is certainly also an excellent starting point for the development of even more performing surfaces for having better healing in the oral surgical procedures related to dental implant positioning., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Luigi Laino et al.)

In this study we used a biocomplex constructed from dental pulp stem/progenitor cells (DPCs) and a collagen sponge scaffold for oro-maxillo-facial (OMF) bone tissue repair in patients requiring extraction of their third molars. The experiments were carried out according to our Internal Ethical Committee Guidelines and written informed consent was obtained from the patients. The patients presented with bilateral bone reabsorption of the alveolar ridge distal to the second molar secondary to impaction of the third molar on the cortical alveolar lamina, producing a defect without walls, of at least 1.5 cm in height. This clinical condition does not permit spontaneous bone repair after extraction of the third molar, and eventually leads to loss also of the adjacent second molar. Maxillary third molars were extracted first for DPC isolation and expansion. The cells were then seeded onto a collagen sponge scaffold and the obtained biocomplex was used to fill in the injury site left by extraction of the mandibular third molars. Three months after autologous DPC grafting, alveolar bone of patients had optimal vertical repair and complete restoration of periodontal tissue back to the second molars, as assessed by clinical probing and X-rays. Histological observations clearly demonstrated the complete regeneration of bone at the injury site. Optimal bone regeneration was evident one year after grafting. This clinical study demonstrates that a DPC/collagen sponge biocomplex can completely restore human mandible bone defects and indicates that this cell population could be used for the repair and/or regeneration of tissues and organs.

Dental pulp stem cells (DPSCs) can be found within the "cell rich zone" of dental pulp. Their embryonic origin, from neural crests, explains their multipotency. Up to now, two groups have studied these cells extensively, albeit with different results. One group claims that these cells produce a "dentin-like tissue", whereas the other research group has demonstrated that these cells are capable of producing bone, both in vitro and in vivo. In addition, it has been reported that these cells can be easily cryopreserved and stored for long periods of time and still retain their multipotency and bone-producing capacity. Moreover, recent attention has been focused on tissue engineering and on the properties of these cells: several scaffolds have been used to promote 3-D tissue formation and studies have demonstrated that DPSCs show good adherence and bone tissue formation on microconcavity surface textures. In addition, adult bone tissue with good vascularization has been obtained in grafts. These results enforce the notion that DPSCs can be used successfully for tissue engineering., ((c) 2008 Wiley-Liss, Inc.)

Harvesting bone for autologous grafting is a daily problem encountered by craniofacial and oral surgeons. Stem cells derived from human dental pulp are able to differentiate in osteoblasts and are a potential source of autologous bone produced in vitro. However, as stem cells are characterized by self-renewing and commitment in several cellular subtypes (ie, pluripotential differentiation), some concerns may arise as regards their potential uncontrolled proliferation. To screen the behavior of osteoblasts derived from human pulpar stem cells (ODHPSCs), we used microarray techniques to identify genes that are differently regulated in ODHPSC in comparison to normal osteoblasts (NOs). Osteoblasts derived from human pulpar stem cells were obtained from human dental pulp, and cells were selected using a cytometer. The cell profile was c-kit+/CD34+/STRO-1+/CD45-. These cells were capable of differentiation of osteoblasts in vitro. By using DNA microarrays containing 19,200 genes, we identified in ODHPSC some genes whose expression was significantly up- and downregulated compared to NO. The differentially expressed genes have different functional activities: (a) cell differentiation, (b) developmental maturation, (c) cell adhesion, and (d) production of cytoskeleton elements. Thus, some molecular differences exist between NO and ODHPSC, although the previously considered histologic parameters show a normal phenotype.

Human tissues are different in term of regenerative properties. Stem cells are a promising tool for tissue regeneration, thanks to their particular characteristics of proliferation, differentiation and plasticity. Several "loci" or "niches" within the adult human body are colonized by a significant number of stem cells. However, access to these potential collection sites often is a limiting point. The interaction with biomaterials is a further point that needs to be considered for the therapeutic use of stem cells. Dental pulp stem cells (DPSCs) have been demonstrated to answer all of these issues: access to the collection site of these cells is easy and produces very low morbidity; extraction of stem cells from pulp tissue is highly efficiency; they have an extensive differentiation ability; and the demonstrated interactivity with biomaterials makes them ideal for tissue reconstruction. SBP-DPSCs are a multipotent stem cell subpopulation of DPSCs which are able to differentiate into osteoblasts, synthesizing 3D woven bone tissue chips in vitro and that are capable to synergically differentiate into osteoblasts and endotheliocytes. Several studied have been performed on DPSCs and they mainly found that these cells are multipotent stromal cells that can be safety cryopreserved, used with several scaffolds, that can extensively proliferate, have a long lifespan and build in vivo an adult bone with Havers channels and an appropriate vascularization. A definitive proof of their ability to produce dentin has not been yet done. Interestingly, they seem to possess immunoprivileges as they can be grafted into allogenic tissues and seem to exert anti-inflammatory abilities, like many other mesenchymal stem cells. The easy management of dental pulp stem cells make them feasible for use in clinical trials on human patients.

It is not known whether cells derived from stem cells retain their differentiation and morpho-functional properties after long-term cryopreservation. This information is of importance to evaluate their potential for long-term storage with a view to subsequent use in therapy. Here, we describe the morpho-functional properties of dental pulp stem cells (SBP-DPSCs), and of their differentiated osteoblasts, recovered after long-term cryopreservation. After storage for 2 years, we found that stem cells are still capable of differentiation, and that their differentiated cytotypes proliferate and produce woven bone tissue. In addition, cells still express all their respective surface antigens, confirming cellular integrity. In particular, SBP-DPSCs differentiated into pre-osteoblasts, showing diffuse positivity for ALP, BAP, RUNX-2, and calcein. Recovered osteoblasts expressed bone-specific markers and were easily recognizable ultrastructurally, with no alterations observed at this level. In addition, after in vivo transplantation, woven bone converted into a 3D lamellar bone type. Therefore, dental pulp stem cells and their osteoblast-derived cells can be long-term cryopreserved and may prove to be attractive for clinical applications.

To harvest bone for autologous grafting is a daily problem encountered by craniofacial and oral surgeons. Stem cells derived from human dental pulp are able to differentiate in osteoblasts and are a potential source of autologous bone produced in vitro. The authors describe their preliminary results in this new field with its potential application in craniomaxillofacial surgery. Dental pulp was gently extracted from 34 human permanent teeth (all third molars) of patients 19 to 37 years of age. After they were digested, the cells were selected using a cytometer for c-kit, STRO-1, CD34, CD45, and then for CD44 and RUNX-2. This study, made on a considerable number of cases, provided evidence that dental pulp is extremely rich in stem cells, which were c-kit+/CD34+/STRO-1+/CD45-, capable of differentiation toward several stromal-derived differentiated cells and mainly osteoblasts. These findings, supported by the large number of cases, are of great interest for tissue regeneration, tissue-based clinical therapies, and transplantation.

Stem cells were obtained from deciduous dental pulp of healthy subjects, aged 6-10 years. This stem cell population was cultured, expanded, and specifically selected, detecting using a FACsorter, c-kit, CD34, and STRO-1 antigen expression. Then, c-kit+/CD34+/STRO-1+ cells were replaced in the culture medium added of 20% FBS, leading to osteoblast differentiation. In fact, these cells, after a week, showed a large positivity for CD44, osteocalcin, and RUNX-2 markers. To achieve an adipocytic differentiation, cells, after sorting, were challenged with dexamethason 10(-8) mM in the same culture medium. To obtain myotube fusion, sorted cells were co-cultured in ATCC medium with mouse myogenic C2C12 cells and, after a week, human stem cell nuclei were found to be able to fuse, forming myotubes. Differentiated osteoblasts, as assessed by a large positivity to several specific antibodies, after 30 days of culture and already in vitro, started to secrete an extracellular mineralized matrix, which, 2 weeks later, built a considerable number of 3D woven bone samples, which showed a strong positivity to alkaline phosphatase (ALP), alizarin red, calcein, other than to specific antibodies. These bone samples, after in vivo transplantation into immunosuppressed rats, were remodeled in a lamellar bone containing entrapped osteocytes. Therefore, this study provides strong evidence that human deciduous dental pulp is an approachable "niche" of stromal stem cells, and that it is an ideal source of osteoblasts, as well as of mineralized tissue, ready for bone regeneration, transplantation, and tissue-based clinical therapies., (Copyright 2005 Wiley-Liss, Inc.)

Unlabelled: Stem cells, derived from human adult dental pulp of healthy subjects 30-45 years of age, were cultured, and cells were selected using a FACSorter. A new c-kit+/CD34+/CD45- cell population of stromal bone producing cells (SBP/DPSCs) was selected, expanded, and cultured. These SBP/DPSCs are highly clonogenic and, in culture, differentiate into osteoblast precursors (CD44+/RUNX-2+), still capable of self-renewing, and then in osteoblasts, producing, in vitro, a living autologous fibrous bone (LAB) tissue, which is markedly positive for several bone antibodies. This tissue constitute an ideal source of osteoblasts and mineralized tissue for bone regeneration. In fact, after in vivo transplantation into immunocompromised rats, LAB formed lamellar bone-containing osteocytes., Introduction: Recently it has been reported that human dental pulp stem cells (DPSCs) are detectable, in humans, only up to the age of 30 years and that they are able to produce in vitro only sporadic calcified nodules and to form, after transplantation in vivo, a mineralized tissue., Materials and Methods: Stem cells, derived from human adult dental pulp of healthy subjects 30-45 years of age, were cultured, and cells were selected using a FACSorter. Light microscope, histochemistry, immunofluorescence, and RT-PCR analyses were performed to study both stem and differentiating cells., Results and Conclusions: A new c-kit+/CD34+/CD45- cell population of stromal bone producing cells (SBP/DPSCs) has been selected by FACSorting, expanded, and cultured. These SBP/DPSCs are highly clonogenic and, in culture, differentiate into osteoblast precursors (CD44+/RUNX-2+), still capable of self-renewing, and in osteoblasts, producing, in vitro, a living autologous fibrous bone (LAB) tissue. This new-formed tissue is markedly positive for several antibodies for bone, including osteonectin, bone sialoprotein, osteocalcin, fibronectin, collagen III, and bone alkaline phosphatase (BALP). Cells producing LAB can be stored at -80 degrees C for a long period of time and are an extraordinary source of osteoblasts and mineralized fibrous bone tissue. In this study, we also showed that, in aged humans, stem cells can be detected from their pulps. The produced LAB is a fibrous bone tissue resembling the human bone during mineralization, with an external layer formed by osteoblasts markedly positive for osteocalcin. This newly formed tissue constitute an ideal source of osteoblasts and mineralized tissue for bone regeneration. In fact, after in vivo transplantation into immunocompromised rats, LAB formed lamellar bone containing osteocytes.

Human tissues are different in term of regenerative properties. Stem cells are a promising tool for tissue regeneration, thanks to their particular characteristics of proliferation, differentiation and plasticity. Several "loci" or "niches" within the adult human body are colonized by a significant number of stem cells. However, access to these potential collection sites often is a limiting point. The interaction with biomaterials is a further point that needs to be considered for the therapeutic use of stem cells. Dental pulp stem cells (DPSCs) have been demonstrated to answer all of these issues: access to the collection site of these cells is easy and produces very low morbidity; extraction of stem cells from pulp tissue is highly efficiency; they have an extensive differentiation ability; and the demonstrated interactivity with biomaterials makes them ideal for tissue reconstruction. SBP-DPSCs are a multipotent stem cell subpopulation of DPSCs which are able to differentiate into osteoblasts, synthesizing 3D woven bone tissue chips in vitro and that are capable to synergically differentiate into osteoblasts and endotheliocytes. Several studied have been performed on DPSCs and they mainly found that these cells are muitipotent stromal cells that can be safety cryopreserved, used with several scaffolds, that can extensively proliferate, have a long lifespan and build in vivo an adult bone with Havers channels and an appropriate vascularization. A definitive proof of their ability to produce dentin has not been yet done. Interestingly, they seem to possess immunoprivileges as they can be grafted into allogenic tissues and seem to exert anti-inflammatory abilities, like many other mesenchymal stem cells. The easy management of dental pulp stem cells make them feasible for use in clinical trials on human patients. [ABSTRACT FROM AUTHOR]

Objective The major challenge for contemporary dentistry is restoration of missing teeth; currently, dental implantation is the treatment of choice in this circumstance. In the present study, we assessed the interaction between implants and Dental Pulp Stem Cells (DPSCs) in vitro by means of 3D cell culture in order to better simulate physiological conditions. Methods Sorted CD34 + DPSCs were seeded onto dental implants having either a rough surface (TriVent) or one coated with a ceramic layer mimicking native bone (TiUnite). We evaluated preservation of DPSC viability during osteogenic differentiation by an MTT assay and compared mineralized matrix deposition with SEM analysis and histological staining; temporal expression of osteogenic markers was evaluated by RT-PCR and ELISA. Results Both surfaces are equally biocompatible, preserve DPSC viability, stimulate osteogenic differentiation, and increase the production of VEGF. A slight difference was observed between the two surfaces concerning the speed of DPSC differentiation. Significance Our study of the two implant surfaces suggests that TriVent, with its roughness, is capable of promoting cell differentiation a bit earlier than the TiUnite surface, although the latter promotes greater cell proliferation. [ABSTRACT FROM AUTHOR]