Single-Cell Transcriptomic Profiling of Human Dental Pulp in Sound and Carious Teeth: A Pilot Study

A comprehensive understanding of dental pulp cellular compositions and their molecular responses to infection are crucial for the advancement of regenerative dentistry. Here, we presented a pilot study of single-cell transcriptomic profiles of 6,810 pulpal cells isolated from a sound human maxillary third molar and three carious teeth with enamel and deep dental caries. We observed altered immune cell compositions of the dental pulp in deep, but not enamel ones. Differential expression analysis revealed up-regulation of several pro-inflammatory, anti-inflammatory, and mineralization-related genes in the immune and stromal cells of the deep dental caries. Making use of an algorithm for predicting cell-to-cell interactions from single-cell transcriptomic profiles, we showed an increase in cell-cell interactions between B cells, plasma cells and macrophages, and other cell types in deep dental caries, including those between TIMP1 (odontoblasts)—CD63 (myeloid cells), and CCL2 (macrophages)—ACKR1 (endothelial cells). Collectively, our work highlighted the single-cell level gene regulations and intercellular interactions in the dental pulps in health and disease.

Application of collagen and mesenchymal stem cells in regenerative dentistry

: Collagen is an important macromolecule of extracellular matrix (ECM) in bones, teeth, and temporomandibular joints. Mesenchymal stem cells (MSCs) interact with the components of the ECM such as collagen, proteoglycans, glycosaminoglycans (GAGs), and several proteins on behalf of variable matrix elasticity and bioactive cues. Synthetic collagen-based biomaterials could be effective scaffolds for regenerative dentistry applications due to mimicking of host tissues’ ECM. These biomaterials are biocompatible, biodegradable, readily available, and non-toxic to cells whose capability promotes cellular response and wound healing in the craniofacial region. Collagen could incorporate other biomolecules to induce mineralization in calcified tissues such as bone and tooth. Moreover, the addition of these molecules or other polymers to collagen-based biomaterials could enhance mechanical properties, which is important in load-bearing areas such as the mandible. A literature review was performed via reliable internet database (mainly PubMed) based on MeSH keywords. This review first describes the properties of collagen as a key protein in the structure of hard tissues. Then, it introduces different types of collagens, the correlation between collagen and MSCs, and the methods used to modify collagen in regenerative dentistry including recent progression on the regeneration of periodontium, dentin-pulp complex, and temporomandibular joint by applying collagen. Besides, the prospects and challenges of collagen-based biomaterials in the craniofacial region pointes out.

Application of Selected Biomaterials and Stem Cells in the Regeneration of Hard Dental Tissue in Paediatric Dentistry—Based on the Current Literature

Currently, the development of the use of biomaterials and their application in medicine is causing rapid changes in the fields of regenerative dentistry. Each year, new research studies allow for the discovery of additional possibilities of dental tissue restoration. The structure and functions of teeth are complex. They consist of several diverse tissues that need to act together to ensure the tooth’s function and durability. The integrity of a tooth’s enamel, dentin, cementum, and pulp tissue allows for successful mastication. Biomaterials that are needed in dentistry must withstand excessive loading forces, be biocompatible with the hosts’ tissues, and stable in the oral cavity environment. Moreover, each tooth’s tissue, as well as aesthetic qualities in most cases, should closely resemble the natural dental tissues. This is why tissue regeneration in dentistry is such a challenge. This scientific research focuses on paediatric dentistry, its classification of caries, and the use of biomaterials in rebuilding hard dental tissues. There are several methods described in the study, including classical conservative methods such as caries infiltration or stainless-steel crowns. Several clinical cases are present, allowing a reader to better understand the described methods. Although the biomaterials mentioned in this work are artificial, there is currently ongoing research regarding clinical stem cell applications, which have a high potential for becoming one of the most common techniques of lost dental-tissue regeneration in the near future. The current state of stem cell development is mentioned, as well as the various methods of its possible application in dentistry.

Potential utilization of glycerol as crosslinker in starch films for application in Regenerative Dentistry

Periodontal disease results in damage to dental insertion apparatus. Regenerative procedures are proposed to replace lost structures in the context of guided tissue regeneration (GTR), guided bone regeneration (GBR) techniques and frequently associate bone substitutes with physical barriers aiming at greater longevity and improvement of aesthetic pattern. This study evaluates the possibility of using glycerol as a starch films modifying agent, acting as a cross-linking agent, without compromising its plasticizing effect. Biodegradable cassava starch films were prepared incorporating glycerol at concentrations of 0, 15, 20, 30 and 40% aiming application at dental regenerative procedures. The characterization of films by microscopy (SEM), thermal analysis (DSC), spectroscopic (UV / Vis., FTIR, XRD), mechanical (Traction), and analysis of protein swelling, degradation and diffusion and physiological temperature) showed that the incorporation of glycerol in up to 20% attributed to the films a plasticizer character and in higher concentrations, conferred a greater interaction of glycerol (crosslinking) with the starch chains and a degradation time that allows the physical barrier in RTG and ROG. The films presented mechanical resistance, malleability and permissiveness to protein diffusion in the in vitro assays, which meet the current attributes that guide the use of these resources in biomaterials.

МЕЗЕНХІМАЛЬНІ СТОВБУРОВІ КЛІТИНИ ОДОНТОГЕННОГО ПОХОДЖЕННЯ: ПЕРСПЕКТИВИ ТА МОЖЛИВОСТІ РЕГЕНЕРАТИВНОЇ МЕДИЦИНИ

Мета: Провести аналіз літературних джерел у напрямку науково-теоретичних та клінічних аспек- тів щодо можливостей використання мезенхімаль- них стовбурових клітин, отриманих з різних джерел щелепно-лицевої ділянки. Матеріали і методи: Під час дослідження викорис- тано бібліосемантичний метод та структурно-логіч- ний аналіз. Для пошуку сучасної наукової літератури були використані електронні бази даних PubMed, MEDLINE, Scopus, Web of Science та EMBASE за клю- човими словами «regenerative medicine», «regenerative dentistry», «stem cells», «dental mesenchymal stem cells», «stem cell therapy», «tissue engineering». Висновки: На основі проведеного аналізу літера- тури прослідковується неабиякий інтерес науковців до стовбурових клітин одонтогенного походження та їх використання у регенеративній практиці не лише стоматологічного спрямування, але і для ліку- вання соматичних хвороб різного генезу. Це пов’язано із неінвазивним та більш простим методом забору матеріалу, порівняно із кістковим мозком людини чи ембріональними тканинами. Стовбурові клітини різ- няться за походженням, диференційною активністю та джерелом їх отримання, а також мають ваго- мий потенціал до диференціації за напрямком різних клітинних ліній залежно від впливу факторів росту та живильного середовища. При одержанні нових чистих культур вдається встановити їх походження шляхом ідентифікації експресії маркерів, характерних для стовбурових клітин. Тим не менш, незважаючи на високі очікування від подальшого розвитку реге- неративної терапії, науковцям необхідно детальніше вивчити можливості використання цих клітин на етапах клінічного випробування, дослідити імуноло- гічну поведінку стовбурових клітин одонтогенного походження в тому чи іншому середовищі.

Challenges and strategy in treatment with exosomes for cell-free-based tissue engineering in dentistry

In dentistry, problems of craniofacial, osteochondral, periodontal tissue, nerve, pulp or endodontics injuries, and osteoarthritis need regenerative therapy. The use of stem cells in dental tissue engineering pays a lot of increased attention, but there are challenges for its clinical applications. Therefore, cell-free-based tissue engineering using exosomes isolated from stem cells is regarded an alternative approach in regenerative dentistry. However, practical use of exosome is restricted by limited secretion capability of cells. For future regenerative treatment with exosomes, efficient strategies for large-scale clinical applications are being studied, including the use of ceramics-based scaffold to enhance exosome production and secretion which can resolve limited exosome secretory from the cells when compared with the existing methods available. Indeed, more research needs to be done on these strategies going forward.

Word of caution: negative impact of mouthwashes on folded Platelet-Rich Fibrin (F- PRF) membrane viability

Backround: The number of clinical application of different platelet-rich fibrin (PRF) membranes has increased in regenerative medicine including regenerative dentistry. Intact platelets, leukocytes and stem cells of PRF play a crucial role in the local bone augmentation releasing cytokines and growth factors. An integral part of the postsurgical management is the application of mouthwashes especially chlorhexidine-digluconate, which is recommended in order to prevent postoperative infections. In some cases there is possibility that there is contact between the mouthwash and PRF membrane. The impact of mouthwashes on cell viability of folded F-PRF was tested. Methods: 3 mouthwash brands were tested: Chorsodyl, Listerine 6 in 1 and Elmex Sensitive Plus using MTT viability assay after 30 seconds treatment and 72 hours treatment (twice daily for 30 seconds). The membrane samples were incubated in cell culture conditions. Results: 30 seconds of mouthwash treatment diminished the fresh F-PRF viability significantly by 15-21% depending on the agent. After 72 hours of treatment the viability loss was ~50%. Conclusion: The decreased number of platelets and other blood cells can not launch optimal bone morphogenesis. The MTT assay is cheap, reliable and simple method to assess the platelet and cellular viability and potential regenerative capacity of F-PRF membrane, or any platelet-rich product. The isolation of the PRF membrane from oral liquids and/or application of less aggressive mouthwashes is recommended for at least 5-7 days after PRF surgery.

Contact Angle and Cell Adhesion of Micro/Nano-Structured Poly (Lactic-Co-Glycolic Acid) Membranes for Dental Regenerative Therapy

Biodegradable membranes are used in regenerative dentistry for guided tissue regeneration (GTR) and guided bone regeneration (GBR). In this study, patterned poly (lactic-co-glycolic acid) (PLGA) membranes with groove, pillar, and hole structures were successfully fabricated by thermal nanoimprinting. Their surfaces were evaluated for topography by scanning electron microscopy and laser microscopy, for hydrophobicity/hydrophilicity by contact angle analysis, and for MC3T3-E1 cell adhesion. The sizes of the patterns on the surfaces of the membranes were 0.5, 1.0, and 2.0 μm, respectively, with the height/depth being 1.0 μm. The pillared and holed PLGA membranes were significantly more hydrophobic than the non-patterned PLGA membranes (p < 0.05). However, the 0.5 μm- and 1.0 μm-grooved PLGA membranes were significantly more hydrophilic than the non-patterned PLGA membranes (p < 0.05). The 0.5 μm-grooved, pillared, and holed membranes exhibited significantly superior adhesion to the MC3T3-E1 cells than the non-patterned PLGA (p < 0.05). These results suggest that patterned PLGA membranes can be clinically used for GTR and GBR in the dental regeneration field.

Cell-Based Transplantation versus Cell Homing Approaches for Pulp-Dentin Complex Regeneration

Regenerative dentistry has paved the way for a new era for the replacement of damaged dental tissues. Whether the causative factor is dental caries, trauma, or chemical insult, the loss of the pulp vitality constitutes one of the major health problems worldwide. Two regenerative therapies were introduced for a fully functional pulp-dentin complex regeneration, namely, cell-based (cell transplantation) and cell homing (through revascularization or homing by injection of stem cells in situ or intravenously) therapies, with each demonstrating advantages as well as drawback, especially in clinical application. The present review is aimed at elaborating on these two techniques in the treatment of irreversibly inflamed or necrotic pulp, which is aimed at regenerating a fully functional pulp-dentin complex.

Chitosan-Based Scaffold for Mineralized Tissues Regeneration

Conventional bone grafting procedures used to treat bone defects have several limitations. An important aspect of bone tissue engineering is developing novel bone substitute biomaterials for bone grafts to repair orthopedic defects. Considerable attention has been given to chitosan, a natural biopolymer primarily extracted from crustacean shells, which offers desirable characteristics, such as being biocompatible, biodegradable, and osteoconductive. This review presents an overview of the chitosan-based biomaterials for bone tissue engineering (BTE). It covers the basic knowledge of chitosan in terms of biomaterials, the traditional and novel strategies of the chitosan scaffold fabrication process, and their advantages and disadvantages. Furthermore, this paper integrates the relevant contributions in giving a brief insight into the recent research development of chitosan-based scaffolds and their limitations in BTE. The last part of the review discusses the next-generation smart chitosan-based scaffold and current applications in regenerative dentistry and future directions in the field of mineralized tissue regeneration.