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Dental and maxillofacial diseases are always accompanied by complicated hard and soft tissue defects, involving bone, teeth, blood vessels and nerves, which are difficult to repair and severely affect the life quality of patients. Recently, extracellular vesicles (EVs) secreted by all types of cells and extracted from body fluids have gained more attention as potential solutions for tissue regeneration due to their special physiological characteristics and intrinsic signaling molecules. Compared to stem cells, EVs present lower immunogenicity and tumorigenicity, cause fewer ethical problems, and have higher stability. Thus, EV therapy may have a broad clinical application in regenerative dentistry. Herein, we reviewed the currently available literature regarding the functional roles of EVs in oral and maxillofacial tissue regeneration, including in maxilla and mandible bone, periodontal tissues, temporomandibular joint cartilage, dental hard tissues, peripheral nerves and soft tissues. We also summarized the underlying mechanisms of actions of EVs and their delivery strategies for dental tissue regeneration. This review would provide helpful guidelines and valuable insights into the emerging potential of EVs in future research and clinical applications in regenerative dentistry. [ABSTRACT FROM AUTHOR]

Abstract Dental and maxillofacial diseases are always accompanied by complicated hard and soft tissue defects, involving bone, teeth, blood vessels and nerves, which are difficult to repair and severely affect the life quality of patients. Recently, extracellular vesicles (EVs) secreted by all types of cells and extracted from body fluids have gained more attention as potential solutions for tissue regeneration due to their special physiological characteristics and intrinsic signaling molecules. Compared to stem cells, EVs present lower immunogenicity and tumorigenicity, cause fewer ethical problems, and have higher stability. Thus, EV therapy may have a broad clinical application in regenerative dentistry. Herein, we reviewed the currently available literature regarding the functional roles of EVs in oral and maxillofacial tissue regeneration, including in maxilla and mandible bone, periodontal tissues, temporomandibular joint cartilage, dental hard tissues, peripheral nerves and soft tissues. We also summarized the underlying mechanisms of actions of EVs and their delivery strategies for dental tissue regeneration. This review would provide helpful guidelines and valuable insights into the emerging potential of EVs in future research and clinical applications in regenerative dentistry.

Mesenchymal stem/stromal cells (MSCs) are multipotent cells located in different areas of the human body. The oral cavity is considered a potential source of MSCs because they have been identified in several dental tissues (D-MSCs). Clinical trials in which cells from these sources were used have shown that they are effective and safe as treatments for tissue regeneration. Importantly, immunoregulatory capacity has been observed in all of these populations; however, this function may vary among the different types of MSCs. Since this property is of clinical interest for cell therapy protocols, it is relevant to analyze the differences in immunoregulatory capacity, as well as the mechanisms used by each type of MSC. Interestingly, D-MSCs are the most suitable source for regenerating mineralized tissues in the oral region. Furthermore, the clinical potential of D-MSCs is supported due to their adequate capacity for proliferation, migration, and differentiation. There is also evidence for their potential application in protocols against autoimmune diseases and other inflammatory conditions due to their immunosuppressive capacity. Therefore, in this review, the immunoregulatory mechanisms identified at the preclinical level in combination with the different types of MSCs found in dental tissues are described, in addition to a description of the clinical trials in which MSCs from these sources have been applied. [ABSTRACT FROM AUTHOR]

Fossils of extinct jawless vertebrates are pivotal to deciphering the evolutionary paths that led to the various forms of the vertebrate skeleton. For example, Pteraspidomorphs (stem‐gnathostomes), such as the Ordovician Astraspis, display some of the oldest remains of bony and 'dental' (dentine and enameloid) tissues. However, the identification of the very nature of these early mineralized tissues has been hampered by a lack of unambiguous diagnostic characters. As development is key to identifying the derivation of these tissues, we developed an integrative and generic histogenetic model, testing several ontogenetic scenarios. We illustrate our approach on the basis of the well‐preserved Astraspis samples and show how this can be used to infer key developmental features from extinct species. This study suggests that in the odontodes of Astraspis: (1) the initial curvature of the epithelium was close to the shape of the final external surface; (2) the mesenchymal cells differentiate synchronously in the whole inner periphery; and (3) the capping tissue was produced by both mesenchymal and epithelial cells (enameloid rather than enamel). Astraspis specimens also provide evidence of a dual growth periodicity, possibly homologous to Andresen and von Ebner growth lines observed in amniotes, suggesting this type of dual periodicity may be shared by most vertebrates. We estimated that an Astraspis odontode grew up in around 60–70 days at a rate of 0.5–5 μm/day. The new developmental approach proposed in this study could be a robust framework for critically evaluating the tissues of extinct taxa in the future. [ABSTRACT FROM AUTHOR]

Objective(s): The purpose of this study was to assess the effects of exosomes derived from dental pulp mesenchymal stem cells (DPSCs) on the viability of odontoblast cells. Methods: Exosomes were extracted from human DPSC cells via ultracentrifugation. Scanning electron microscopy and western blot analysis for CD9 and CD81 demonstrated characteristics of exosomes. Developing odontoblasts were exposed to increasing concentrations of exosomes (10-400 ng/ml) over time periods of 24, 48, 72, and 96 hours. Cell viability was evaluated using MTT assays. In addition, real-time PCR was used to assess expression levels of Wnt, betacatenin, PI3K, Akt, Bcl-2, and Bax in cells after 24-96 hours of exposure to 100 and 400 ng/ml exosomes. Results: Odontoblast viability was found to be enhanced by DPSC-derived exosomes, with greater impacts at higher concentrations and time periods of 72-96 hours. Expression of PI3K, AKT, Wnt, beta-catenin, and Bcl-2 were notably upregulated in odontoblasts following 96 hours of DPSC-exosome treatment. Conversely, Bax expression was significantly downregulated. These findings suggest DPSC-exosomes promote odontoblast survival through modulated expression of genes involved in key survival pathways over extended exposure periods. Conclusions: Our findings demonstrated that exosomes derived from DPSC cells possess innate nanoparticle properties, leading to enhanced survival of odontoblast cells. This effect is achieved through the activation of the Wnt/betacatenin and P3K/AKT signaling pathways, ultimately resulting in an increased Bcl2/Bax ratio. [ABSTRACT FROM AUTHOR]

In our work, the effect of a dental Er:YAG pulsed laser and a diamond cylindrical drill with a turbine handpiece on dentin tissue was studied using spectral imaging. The combination of spectral imaging of FTIR microspectroscopy data and subsequent multivariate analysis (hierarchical cluster analysis (HCA) and principal component analysis (PCA)) was shown to unambiguously detect visually indistinguishable structural changes occurring in the hard dental tissue (dentin) depending on the method used for their pre-processing, and to classify and differentiate the identified features at the submicron level with high spatial resolution. The detectable spectral transformations indicate that the preparation of dental tissue with a dental laser leads to significant changes in the organic components of dentin, which may affect adhesion. The use of a diamond cylindrical drill with a turbine handpiece is characterized by a larger area (depth) of the altered hard tissue than in the case of a dental laser for dental cavity preparation. The observed redistribution of the phase composition of the inorganic component in the tissue is associated with the emergence of additional phases of weak calcium phosphates, and changes in the organic component with transformations in the secondary structure of proteins. Active use of the proposed integrated approach in the future will clarify the areas of its applicability to the analysis of biological tissues and pathologies in them, which will help in the clinical setting to choose the optimal personalized approach for patients. [ABSTRACT FROM AUTHOR]

Mesenchymal stem/stromal cells (MSCs) are multipotent cells located in different areas of the human body. The oral cavity is considered a potential source of MSCs because they have been identified in several dental tissues (D-MSCs). Clinical trials in which cells from these sources were used have shown that they are effective and safe as treatments for tissue regeneration. Importantly, immunoregulatory capacity has been observed in all of these populations; however, this function may vary among the different types of MSCs. Since this property is of clinical interest for cell therapy protocols, it is relevant to analyze the differences in immunoregulatory capacity, as well as the mechanisms used by each type of MSC. Interestingly, D-MSCs are the most suitable source for regenerating mineralized tissues in the oral region. Furthermore, the clinical potential of D-MSCs is supported due to their adequate capacity for proliferation, migration, and differentiation. There is also evidence for their potential application in protocols against autoimmune diseases and other inflammatory conditions due to their immunosuppressive capacity. Therefore, in this review, the immunoregulatory mechanisms identified at the preclinical level in combination with the different types of MSCs found in dental tissues are described, in addition to a description of the clinical trials in which MSCs from these sources have been applied.

The creation of buffer (hybrid) layers that provide improved adhesion to two heterogeneous materials is a promising and high-priority research area in the field of dental materials science. In our work, using FTIR and Raman microspectroscopy at the submicron level in a system of dental composites/intact dental enamel, we assessed the molecular features of formation and chemically visualized the hybrid interface formed on the basis of a nature-like adhesive, polydopamine (PDA). It is shown that a homogeneous bioinspired PDA–hybrid interface with an increased content of O-Ca-O bonds can be created using traditional methods of dental tissue pretreatment (diamond micro drilling, acid etching), as well as the subsequent alkalinization procedure and the developed synthesis technology. The development of the proposed technology for accelerated deposition of PDA–hybrid layers, as well as the creation of self-assembled biomimetic nanocomposites with antibacterial properties, may in the future find clinical application for minimally invasive dental restoration procedures. [ABSTRACT FROM AUTHOR]

The aesthetic result in the ceramic restoration of anterior teeth has always been a challenge in clinical practice and, in these cases, success depends on the skills of both the clinician and the dental technician. In current dentistry, the main objective is to pursue aesthetic results while preserving biological structures. Among the various conservative techniques available for anterior restorations, veneers are the most advantageous, compared to traditional crown preparation, both for the amount of tooth structure preserved in the preparation phase and for the direct adhesion on the enamel in the cementation. This article presents a clinical case of no-prep porcelain veneers (no-prep technique) for smile frame restoration. [ABSTRACT FROM AUTHOR]

BACKGROUND: Ectodermal mesenchymal stem cells are a kind of adult stem cells, which are easy to obtain and abundant in source, and play an important role in tissue repair and immune regulation. OBJECTIVE: To summarize the latest progress in the acquisition and application of ectodermal mesenchymal stem cells. METHODS: Web of Science was searched with the key words of “ectodermal mesenchymal stem cells, stem cell therapy, spinal cord injury, neurodegenerative disease, sepsis”. The indexes were original studies and reviews. The retrieval period was from the establishment of the database to 2021. Totally 85 relevant articles were screened out and analyzed and summarized with the document tracing method. RESULTS AND CONCLUSION: (1) Ectodermal mesenchymal stem cells are abundant and easy to obtain, and can be derived from dental tissue, nasal mucosa, and corneal tissue. Similar to mesoderm mesenchymal stem cells, they have the ability of multi-line differentiation and immunomodulatory function. (2) Epidermal mesenchymal stem cells share homology with dental tissue and neural tissue. Ectodermal mesenchymal stem cells have better ability of ligaments and nervous tissue differentiation, so they have unique advantages in dental tissue repair, spinal cord injury repair, neurodegenerative disease treatment and so on, so they have a very broad application prospect. (3) Immunomodulatory function of ectodermal mesenchymal stem cells also cannot be ignored. There is only a small amount of literature reports applied to sepsis and other immune diseases, but studies found that its immune regulation mechanism is same as mesoderm mesenchymal stem cells. In the meanwhile, the acquisition of ectodermal mesenchymal stem cells is less invasive; therefore, ectoderm mesenchymal stem cells have excellent prospects of clinical application. [ABSTRACT FROM AUTHOR]

Background: The most common dental materials are resin composite direct restorative materials and dentin adhesives, which are marketed with different techniques, application recommendations, and compositions, making it difficult to choose the most suitable material and method for different cases.

In our work, the effect of a dental Er:YAG pulsed laser and a diamond cylindrical drill with a turbine handpiece on dentin tissue was studied using spectral imaging. The combination of spectral imaging of FTIR microspectroscopy data and subsequent multivariate analysis (hierarchical cluster analysis (HCA) and principal component analysis (PCA)) was shown to unambiguously detect visually indistinguishable structural changes occurring in the hard dental tissue (dentin) depending on the method used for their pre-processing, and to classify and differentiate the identified features at the submicron level with high spatial resolution. The detectable spectral transformations indicate that the preparation of dental tissue with a dental laser leads to significant changes in the organic components of dentin, which may affect adhesion. The use of a diamond cylindrical drill with a turbine handpiece is characterized by a larger area (depth) of the altered hard tissue than in the case of a dental laser for dental cavity preparation. The observed redistribution of the phase composition of the inorganic component in the tissue is associated with the emergence of additional phases of weak calcium phosphates, and changes in the organic component with transformations in the secondary structure of proteins. Active use of the proposed integrated approach in the future will clarify the areas of its applicability to the analysis of biological tissues and pathologies in them, which will help in the clinical setting to choose the optimal personalized approach for patients.

The creation of buffer (hybrid) layers that provide improved adhesion to two heterogeneous materials is a promising and high-priority research area in the field of dental materials science. In our work, using FTIR and Raman microspectroscopy at the submicron level in a system of dental composites/intact dental enamel, we assessed the molecular features of formation and chemically visualized the hybrid interface formed on the basis of a nature-like adhesive, polydopamine (PDA). It is shown that a homogeneous bioinspired PDA–hybrid interface with an increased content of O-Ca-O bonds can be created using traditional methods of dental tissue pretreatment (diamond micro drilling, acid etching), as well as the subsequent alkalinization procedure and the developed synthesis technology. The development of the proposed technology for accelerated deposition of PDA–hybrid layers, as well as the creation of self-assembled biomimetic nanocomposites with antibacterial properties, may in the future find clinical application for minimally invasive dental restoration procedures.

Biomaterials and stem cells are essential components in the field of regenerative medicine. Various biomaterials have been designed that have appropriate biochemical and biophysical characteristics to mimic the microenvironment of an extracellular matrix. Dental stem cells (DT-MSCs) represent a novel source for the development of autologous therapies due to their easy availability. Although research on biomaterials and DT-MSCs has progressed, there are still challenges in the characteristics of biomaterials and the molecular mechanisms involved in regulating the behavior of DT-MSCs. In this review, the characteristics of biomaterials are summarized, and their classification according to their source, bioactivity, and different biological effects on the expansion and differentiation of DT-MSCs is summarized. Finally, advances in research on the interaction of biomaterials and the molecular components involved (mechanosensors and mechanotransduction) in DT-MSCs during their proliferation and differentiation are analyzed. Understanding the molecular dynamics of DT-MSCs and biomaterials can contribute to research in regenerative medicine and the development of autologous stem cell therapies. [ABSTRACT FROM AUTHOR]

The success of regenerative medicine in various clinical applications depends on the appropriate selection of the source of mesenchymal stem cells (MSCs). Indeed, the source conditions, the quality and quantity of MSCs, have an influence on the growth factors, cytokines, extracellular vesicles, and secrete bioactive factors of the regenerative milieu, thus influencing the clinical result. Thus, optimal source selection should harmonize this complex setting and ensure a well-personalized and effective treatment. Mesenchymal stem cells (MSCs) can be obtained from several sources, including bone marrow and adipose tissue, already used in orthopedic regenerative applications. In this sense, for bone, dental, and oral injuries, MSCs could provide an innovative and effective therapy. The present review aims to compare the properties (proliferation, migration, clonogenicity, angiogenic capacity, differentiation potential, and secretome) of MSCs derived from bone marrow, adipose tissue, and dental tissue to enable clinicians to select the best source of MSCs for their clinical application in bone and oral tissue regeneration to delineate new translational perspectives. A review of the literature was conducted using the search engines Web of Science, Pubmed, Scopus, and Google Scholar. An analysis of different publications showed that all sources compared (bone marrow mesenchymal stem cells (BM-MSCs), adipose tissue mesenchymal stem cells (AT-MSCs), and dental tissue mesenchymal stem cells (DT-MSCs)) are good options to promote proper migration and angiogenesis, and they turn out to be useful for gingival, dental pulp, bone, and periodontal regeneration. In particular, DT-MSCs have better proliferation rates and AT and G-MSC sources showed higher clonogenicity. MSCs from bone marrow, widely used in orthopedic regenerative medicine, are preferable for their differentiation ability. Considering all the properties among sources, BM-MSCs, AT-MSCs, and DT-MSCs present as potential candidates for oral and dental regeneration. [ABSTRACT FROM AUTHOR]

Abstract Background The dentin is a tissue, which is formed by odontoblasts at the pulp interface of the teeth that supports the enamel. Odontoblasts, the cranial neural crest cells are derived from ectodermal mesenchymal stem cells (MSCs) and are long and polarized cells. They are present at the outer surface of dentin and play a prominent role about dentin formation. Recently, attention has been focused on induction of odontoblast using various type of MSCs and effects of the 17ß-estradiol supplementation. In this study, we establish an efficient odonto/osteoblast differentiation protocol using 17ß-estradiol supplementation while comparing the odonto/osteoblast ability of various dental MSCs. Methods Same donor derived four types of dental MSCs namely dental pulp stem cells (DPSCs), stem cells from apical papilla (SCAP), dental follicle stem cells (DFSCs), and periodontal ligament stem cells (PDLSCs) were evaluated for their stemness characteristics and potency towards odonto/osteoblast (Induced odonto/osteoblast) differentiation. Then 17ß-estradiol supplementation of 0 and 10 µM was applied to the odonto/osteoblast differentiation media for 14 days respectively. Furthermore, mRNA and protein levels of odonto/osteoblast markers were evaluated. Results All of the experimental groups displayed stemness characteristics by showing adipocyte and chondrocyte differentiation abilities, expression for cell surface markers and cell proliferation capacity without any significant differences. Moreover, all dental derived MSCs were shown to have odonto/osteoblast differentiation ability when cultured under specific conditions and also showed positive expression for odontoblast markers at both mRNA and protein level. Among all, DPSCs revealed the higher differentiation potential than other dental MSCs. Furthermore, odonto/osteoblast differentiation potential was enhanced by supplementing the differentiation media with 17ß-estradiol (E2). Conclusions Thus, DPSCs possess higher odonto/osteogenic potential than the SCAPs, DFSCs, PDLSCs and their differentiation capacity can by further enhanced under E2 supplementation.

Objective: The aim of the study was to evaluate the characteristics of dentin ablation with a high pulse repetition rate Q-switching 2.79 lm laser. Materials and methods: Dentin was ablated using a homemade Q-switching Er:YSGG laser with a high pulse repetition rate. Er:YSGG radiation was applied with a pulse energy of 1 or 10mJ for 100 or 3Hz pulse repetition rate, respectively. A scanning electron microscope (SEM) was used to observe the microstructures of dentin samples after ablation. Teeth were irradiated in vitro with a 100 Hz pulse repetition rate under two different modes: free running and Q-switching. A thermocouple was applied to measure the temperature in the pulp cavity during ablation. Results: A 100 or 3Hz Q-switching laser was used to irradiate dentin for 30 and 100 sec, respectively. There was no significant difference in ablation mass loss between the two conditions. The SEM photographs showed more dentinal tubules and no damage in the ablation area when using the 100 Hz Q-switching laser. The temperature of the pulp cavity was maintained below 41°C when using a Q-switching laser. Conclusions: The Q-switching Er:YSGG laser with a high pulse repetition rate exhibited greater ablation efficiency and better morphology than the low pulse repetition rate Q-switching laser. The experimental results also demonstrate the significant advantage of the Q-switching laser over free-running lasers for protecting dental pulp tissue. The Q-switching Er:YSGG laser with a high pulse repetition rate is expected to become an efficient new dental tool. [ABSTRACT FROM AUTHOR]

Abstract Odontoblasts are cells that contribute to the formation of the dental pulp complex. The differentiation of dental tissue-derived mesenchymal stem cells into odontoblasts comprises many factors and signaling pathways. Noncoding RNAs (ncRNAs), comprising a substantial part of poly-A tail mature RNAs, are considered “transcriptional noise.” Emerging evidence has shown that ncRNAs have key functions in the differentiation of mesenchymal stem cells. In this review, we discussed two major types of ncRNAs, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), in terms of their role in the odontogenic differentiation of dental tissue-derived stem cells. Recent findings have demonstrated important functions for miRNAs and lncRNAs in odontogenic differentiation. It is expected that ncRNAs will become promising therapeutic targets for dentin regeneration based on stem cells.

Biomaterials and stem cells are essential components in the field of regenerative medicine. Various biomaterials have been designed that have appropriate biochemical and biophysical characteristics to mimic the microenvironment of an extracellular matrix. Dental stem cells (DT-MSCs) represent a novel source for the development of autologous therapies due to their easy availability. Although research on biomaterials and DT-MSCs has progressed, there are still challenges in the characteristics of biomaterials and the molecular mechanisms involved in regulating the behavior of DT-MSCs. In this review, the characteristics of biomaterials are summarized, and their classification according to their source, bioactivity, and different biological effects on the expansion and differentiation of DT-MSCs is summarized. Finally, advances in research on the interaction of biomaterials and the molecular components involved (mechanosensors and mechanotransduction) in DT-MSCs during their proliferation and differentiation are analyzed. Understanding the molecular dynamics of DT-MSCs and biomaterials can contribute to research in regenerative medicine and the development of autologous stem cell therapies.

Background: The dentin is a tissue, which is formed by odontoblasts at the pulp interface of the teeth that supports the enamel. Odontoblasts, the cranial neural crest cells are derived from ectodermal mesenchymal stem cells (MSCs) and are long and polarized cells. They are present at the outer surface of dentin and play a prominent role about dentin formation. Recently, attention has been focused on induction of odontoblast using various type of MSCs and effects of the 17ß-estradiol supplementation. In this study, we establish an efficient odonto/osteoblast differentiation protocol using 17ß-estradiol supplementation while comparing the odonto/osteoblast ability of various dental MSCs. Methods: Same donor derived four types of dental MSCs namely dental pulp stem cells (DPSCs), stem cells from apical papilla (SCAP), dental follicle stem cells (DFSCs), and periodontal ligament stem cells (PDLSCs) were evaluated for their stemness characteristics and potency towards odonto/osteoblast (Induced odonto/osteoblast) differentiation. Then 17ß-estradiol supplementation of 0 and 10 µM was applied to the odonto/osteoblast differentiation media for 14 days respectively. Furthermore, mRNA and protein levels of odonto/osteoblast markers were evaluated. Results: All of the experimental groups displayed stemness characteristics by showing adipocyte and chondrocyte differentiation abilities, expression for cell surface markers and cell proliferation capacity without any significant differences. Moreover, all dental derived MSCs were shown to have odonto/osteoblast differentiation ability when cultured under specific conditions and also showed positive expression for odontoblast markers at both mRNA and protein level. Among all, DPSCs revealed the higher differentiation potential than other dental MSCs. Furthermore, odonto/osteoblast differentiation potential was enhanced by supplementing the differentiation media with 17ß-estradiol (E2). Conclusions: Thus, DPSCs possess higher odonto/osteogenic potential than the SCAPs, DFSCs, PDLSCs and their differentiation capacity can by further enhanced under E2 supplementation. [ABSTRACT FROM AUTHOR]

Background: X-linked hypophosphatemia (XLH) is a rare genetic disease in which increased phosphate loss in the kidney leads to hypophosphatemia and prevents normal mineralization of bone and tooth hard tissues. Purpose: To analyze the impact that this genetic pathology has on dental and periodontal hard tissues such as dentin, cementum, and alveolar bone. Methods: An integrative review of literature was carried out, through PubMed and SciELO searches. The search terms were: X-linked hypophosphatemia, dental tissue, periodontium, dentin, enamel, cementum, and alveolar bone. The search was restricted to literature in Spanish and English published between 2000 and 2020. Results: Thirteen articles that reported the impact of hypophosphatemia on dental tissues, mainly on dentin and cementum, were included. A negative impact of hypophosphatemia on periodontal tissues was also reported, especially on alveolar bone. Conclusions: The findings show us that XLH alters the structure of oral cavity hard tissues, affecting the quality of life of patients. Further research on the effect and behavior of this pathology on hard tissues of the oral cavity as well as its behavior as a risk factor for the presence of dental and periodontal disease is necessary. [ABSTRACT FROM AUTHOR]

The tremendous technological and dental material progress led to a progressive advancement of treatment technologies and materials in restorative dentistry and prosthodontics. In this approach, CAD/CAM restorations have proven to be valuable restorative dental materials in both provisional and definitive restoration, owing to multifarious design, improved and highly tunable mechanical, physical and morphological properties. Thus far, the dentistry market offers a wide range of CAD/CAM restorative dental materials with highly sophisticated design and proper characteristics for a particular clinical problem or multiple dentistry purposes. The main goal of this research study was to comparatively investigate the micro-mechanical properties of various CAD/CAM restorations, which are presented on the market and used in clinical dentistry. Among the investigated dental specimens, hybrid ceramic-based CAD/CAM presented the highest micro-mechanical properties, followed by CAD/CAM PMMA-graphene, while the lowest micro-mechanical features were registered for CAD/CAM multilayered PMMA.

BACKGROUND: Dental tissue-derived mesenchymal stem cells can be isolated from different tissues such as dental pulp, periodontal ligament, exfoliated deciduous teeth, apical papilla, dental follicle, gingiva and other tissues. A large number of experimental studies have found that the effect of dental tissue-derived mesenchymal stem cells on immune cells may depend on many factors such as the surrounding microenvironment, the tissue source of the stem cells and the type of immune cell preparation. Moreover, it has been proved that activated immune cells can up-regulate the immunomodulatory activity of dental tissue-derived mesenchymal stem cells, and this research on the immunomodulatory activity of dental tissue-derived mesenchymal stem cells will lay the foundation for its application in regenerative repair. OBJECTIVE: To review the research progress of dental tissue-derived mesenchymal stem cells in immune regulation. METHODS: A computer-based search of China Biology Medicine (CBM), CNKI, PubMed and Elsevier databases was performed, and the search terms included "immunomodulation; immune system; mesenchymal stem cells; regeneration; oral diseases; pathogenic bacteria; dental-tissue." We reviewed related articles regarding the immunoregulation of dental tissue-derived mesenchymal stem cells published from 2000 to 2019, including reviews, basic research, and clinical research. Preliminary screening of reading titles and abstracts was performed to exclude documents that are not related to the topic of the article. Based on the inclusion and exclusion criteria, 88 articles were finally included for result analysis. RESULTS AND CONCLUSION: In recent years, dental tissue-derived mesenchymal stem cells have been widely used, but the immunomodulatory effect of dental tissue-derived mesenchymal stem cells is not clear. The interaction between dental tissue-derived mesenchymal stem cells and immune cells represents a mechanism that contributes to the study of tissue homeostasis and inflammatory diseases. Therefore, immunomodulation-based strategies may be a very promising tool. This paper reviews the complex mechanism of the interaction between dental tissue-derived mesenchymal stem cells and immune cells and discusses the potential significance of its mediated immunoregulation in the progression of oral diseases and oral tissue regeneration. [ABSTRACT FROM AUTHOR]

Cryopreservation abilities of dental tissue-derived mesenchymal stromal cells (DMSCs) including dental pulp stem cells (DPSCs) and dental follicle stem cells (DFSC) play an important role in the applications of these cells in clinical settings. In this context, we checked whether storage at − 80 °C in 10% DMSO for a longer period has any adverse effect on the functionality and genetic stability. We carried our studies on DPSC and DFSC samples that were revived after a maximum of 5 years of cryopreservation. We observed that even after long-term uncontrolled freezing at − 80 °C, these cells survived and proliferated efficiently. The assessment was made based on their post-thaw morphology, immunophenotypes, differentiation potential, growth kinetics, and genetic features. These cells retained the expression of stemness markers, differentiation ability and maintained their normal karyotype. Our results indicated no significant morphological or immunophenotypic differences between the cryopreserved DMSCs and the fresh DMSCs. Our study implies that mesenchymal stromal cells derived from the dental tissue origin are very robust and do not require any sophisticated preservation protocols. Thus, these can be an ideal source for research, stem cell banking, as well as successful clinical applications in tissue engineering and cell-based therapeutics. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to evaluate the survival rate of lithium disilicate overlays in increasing occlusal vertical dimension (OVD) in the setting of minimally invasive techniques and the restoration thicknesses at different tooth sites. Materials and methods: This is an observational study evaluating 43 lithium disilicate overlays (Lithium IPS e.max Press, Ivoclar Vivadent) on 8 patients, prepared with minimally invasive criteria over a follow-up period between 19 to 45 months (mean follow-up of 32 months). Occlusal vertical dimension's increase was planned using occlusal treatment plan and diagnostic wax-up. Prior to adhesive cementation, restoration thicknesses were measured with a caliber. The survival rate was calculated by Kaplan-Meier analysis. Results: Restoration survival rates at 32 months were 97.7%. One infiltration was observed, no cases of fracture occurred. The greatest thickness in monolithic restorations was detected in the cusp sides of teeth, whereas the thinnest was highlighted in the central fossa. The average amount of dental tissue removed during preparation was 0.98 mm in non-functional cusps, 0.88 mm in functional cusps, and 0.57 mm in the central fossa. Conclusions: Lithium disilicate posterior overlays show an excellent complication-free survival rate, and the material allows for conservative restorations with minimum thickness. Clinical relevance: Monolithic lithium disilicate overlays feature a satisfying 32-month survival rate. The technique allows to perform restorations with a minimal removal of dental tissue, while limiting fractures over time. Its esthetical performance is excellent. [ABSTRACT FROM AUTHOR]

Enamel is the hardest tissue in the vertebrate body. Although variation in enamel microstructure is often linked with diet, the gross proportions of the tissues that compose vertebrate teeth remain relatively unexplored in reptiles. To investigate the patterns of enamel thickness in crocodyliforms, we used micro‐computed tomography scanning to evaluate enamel thickness in teeth of Alligator mississippiensis from rostral, intermediate and caudal locations in the tooth row from an ontogenetic range of animals. We also evaluated enamel thickness in the derived teeth of several extinct crocodyliforms with disparate craniodental morphologies. Our data show that enamel thickness scales isometrically with skull length. We also show that enamel is relatively thicker in caudal teeth than teeth in more rostral positions, concordant with the higher bite forces they experience during feeding. We compared our data with existing enamel thickness data reported from dinosaurs and mammalian taxa to find that archosaurs have markedly thinner enamel than most mammals. These findings serve as a basis for future investigations into the diversity and function of the proportions of dental tissues. [ABSTRACT FROM AUTHOR]

Dental avulsion may be defined as the displacement of the tooth from its socket as a result of trauma. The best possible treatment for an avulsed tooth is replanting it immediately (i.e., less than five minutes). Unfortunately, and most of the times avulsed teeth experience delayed replantation. The success of delayed replantation depends on the vitality of the periodontal ligament cells remaining on the root surface. The chances of root surface damage are higher when tooth replantation is not performed immediately or if the avulsed tooth is not stored in an adequate storage medium. This invariably leads to necrosis of pulp tissue, periodontal ligament cells and thus increasing the possibility of root resorption, which is the main cause of loss of replanted teeth. Isotonic medium is superior to dry storage in the storage of avulsed tooth. Natural storage media are tap water, milk, saline, saliva, coconut water, egg white, propolis extract, green tea extract, aloe vera, pomegranate juice, red mulberry etc. Synthetic storage media are Gatorade, contact lens solution, HBSS, viaspan, emdogain, culture media etc. In this article, we are going to discuss the most suitable media for interim storage of the avulsed tooth by comparing the natural and synthetic storage media. [ABSTRACT FROM AUTHOR]

The aim of this work is to develop a biomimetic interface between the natural tooth tissue and the restorative composite and to study it on the basis of synchrotron micro-FTIR mapping and multidimensional processing of the spectral data array. Using hierarchical cluster analysis of 3D FTIR data revealed marked improvements in the formation of the dentine/adhesive/dental hybrid interface using a biomimetic approach. The use of a biomimetic strategy (application of an amino acid–modified primer, alkaline calcium and a nano-c-HAp–modified adhesive) allowed the formation of a matrix that can be structurally integrated with natural dentine and dental composite. The biomimetic hybrid layer was characterised by homogeneous chemical composition and a higher degree of conversion of the adhesive during polymerisation, which should provide optimal integration of the dental composite with the dentine.

Since dental structures are hard and fragile, cross-sectioning of these materials using ultramicrotomy and other techniques and following micro and nano analysis cause problems. The use of FIB-SEM dual beam platforms is the most convenient solution for investigating the microstructures, site-specifically and in certain geometries. Dual beam platforms allow for imaging at high magnifications and resolutions and simultaneous elemental analysis. In this study, the micro/nano-structural and chemical differences were revealed in dentin and enamel samples. The investigation of dental tissues having different morphologies and chemical components by ion-cross-sectioning is important for the use of FIB-SEM platforms in dentistry in Turkey.

With the development of technology, tissue engineering (TE) has been widely applied in the medical field. In recent years, due to its accuracy and the demands of solid freeform fabrication in TE, three-dimensional printing, also known as additive manufacturing (AM), has been applied for biological scaffold fabrication in craniofacial and dental regeneration. In this review, we have compared several types of AM techniques and summarized their advantages and limitations. The range of printable materials used in craniofacial and dental tissue includes all the biomaterials. Thus, basic and clinical studies were discussed in this review to present the application of AM techniques in craniofacial and dental tissue and their advances during these years, which might provide information for further AM studies in craniofacial and dental TE.

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Although oral dental tissue is a vertebrate attribute, trunk dental tissue evolved in several extinct vertebrate lineages but is rare among living species. The question of which processes trigger dental-tissue formation in the trunk remains open, and would shed light on odontogenesis evolution. Extra-oral dental structures (odontodes) in the trunk are associated with underlying dermal bony plates, leading us to ask whether the formation of trunk bony plates is necessary for trunk odontodes to emerge. To address this question, we focus on Loricarioidei: an extant, highly diverse group of catfish whose species all have odontodes. We examined the location and cover of odontodes and trunk dermal bony plates for all six loricarioid families and 17 non-loricarioid catfish families for comparison. We inferred the phylogeny of Loricarioidei using a new 10-gene dataset, eight timecalibration points, and noise-reduction techniques. Based on this phylogeny, we reconstructed the ancestral states of odontode and bony plate cover, and find that trunk odontodes emerged before dermal bony plates in Loricarioidei. Yet we discovered that when bony plates are absent, other surface bones are always associated with odontodes, suggesting a link between osteogenic and odontogenic developmental pathways, and indicating a remarkable trunk odontogenic potential in Loricarioidei. [ABSTRACT FROM AUTHOR]

Since dental structures are hard and fragile, cross-sectioning of these materials using ultramicrotomy and other techniques and following micro and nano analysis cause problems. The use of FIB-SEM dual beam platforms is the most convenient solution for investigating the microstructures, site-specifically and in certain geometries. Dual beam platforms allow for imaging at high magnifications and resolutions and simultaneous elemental analysis. In this study, the micro/nano-structural and chemical differences were revealed in dentin and enamel samples. The investigation of dental tissues having different morphologies and chemical components by ion-cross-sectioning is important for the use of FIB-SEM platforms in dentistry in Turkey. [ABSTRACT FROM AUTHOR]

Adult stem cells research has been considered the most advanced sort of medical-scientific research, particularly stem cells from human exfoliated deciduous teeth (SHED), which represent an immature stem cell population. The purpose of this review is to describe the current knowledge concerning SHED from full-text scientific publications from 2003 to 2015, available in English language and based on the keyword and/or abbreviations 'stem cells from human exfoliated deciduous teeth (SHED)', and individually presented as to the properties of SHED, immunomodulatory properties of SHED and stem cell banking. In summary, these cell populations are easily accessible by noninvasive procedures and can be isolated, cultured and expanded in vitro, successfully differentiated in vitro and in vivo into odontoblasts, osteoblasts, chondrocytes, adipocytes and neural cells, and present low immune reactions or rejection following SHED transplantation. Furthermore, SHED are able to remain undifferentiated and stable after long-term cryopreservation. In conclusion, the high proliferative capacity, easy access, multilineage differentiation capacity, noninvasiveness and few ethical concerns make stem cells from human exfoliated deciduous teeth the most valuable source of stem cells for tissue engineering and cell-based regenerative medicine therapies. [ABSTRACT FROM AUTHOR]

Raman spectroscopy is rapidly moving from an experimental technique for the analysis of biological molecules to a tool for the real-time clinical diagnosis andin situevaluation of the oral tissue in medical and dental research. The purpose of this study is to identify various applications of Raman spectroscopy, to evaluate the contemporary status, and to explore future directions in the field of dentistry. Several in-depth applications are presented to illustrate Raman spectroscopy in early diagnosis of soft tissue abnormalities. Raman spectroscopy allows researchers to analyze histological and biochemical composition of biological tissues. The technique not only demonstrates its role in the disclosure of dysplasia and malignancy, but also in performing guided biopsies, diagnosing sialoliths, and assessment of surgical margins. Raman spectroscopy is used to identify the molecular structures and their components to give substantial information about the chemical structure properties of these molecules. In this article, we acquaint the utilization of Raman spectroscopy in analyzing the soft tissues in relation to dentistry. [ABSTRACT FROM AUTHOR]

Dentoalveolar tissue engineering is an emerging yet challenging field, considering the lack of suitable materials and difficulty to produce patient-specific hydrogel scaffolds. The present paper aims to produce a 3D printable and tuneable biomaterial by copolymerizing a synthesized water-soluble chitosan derivative called maleic anhydride grafted chitosan (MA-C) with gelatin using genipin, a natural crosslinking agent. Development and testing of this material for 3D printing, degradation, and swelling demonstrated the ability to fabricate scaffolds with controlled physical properties based on pre-determined designs. The MA-C-gelatin copolymer demonstrated excellent biocompatibility, which was verified by analyzing the viability, growth and proliferation of human dental pulp stem cells seeded on MA-C-gelatin constructs through live/dead, alamar blue and DNA quantification assays. Based on the present findings, the proposed material might be a suitable candidate for dentoalveolar tissue engineering, while further research is required to achieve this goal. [Display omitted] • Water-soluble maleic anhydride grafted chitosan (MA-C) was synthesized. • A 3D printable hydrogel was prepared by crosslinking MA-C and gelatin with genipin. • The scaffold properties were tuned by varying the degree of crosslinking. • Cells seeded on these scaffolds showed high cell viability and cell proliferation [ABSTRACT FROM AUTHOR]