Bio-active cements-Mineral Trioxide Aggregate based calcium silicate materials: a narrative review.

Recent advances in the field of endodontics have greatly improved the outcome and success rate of dental materials. For last three decades, there has been great interest in the development of bioactive dental material with the ability to interact and induce surrounding dental tissues to promote regeneration of pulpal and periradicular tissues. As these bioactive materials are mainly based on calcium silicates, they are also referred to as Calcium Silicate materials. The first material introduced was Mineral Tri-oxide Aggregate, which, due to its favourable biological properties, gained importance initially. However, later, due to its drawbacks, liked is colouration, long setting time and difficult manipulation, several modifications were done and newer bioactive materials, such as Biodentine, BioAggregate, Endosequence, Calcium-Enriched Mixture etc., were developed. The main applications of these materials are for pulp capping (direc t/indirec t), pulpotomy, perforation repair, resorption defects, apexogenesis and as retrograde filling materials, apexification and endodontic sealers. This review discusses the various types of bioactive materials, their composition, setting mechanism, and literature evidence for current applications.

Periodontal ligament cells regulate osteogenesis via miR-299-5p in mesenchymal stem cells.

BACKGROUND: The periodontal ligament contains periodontal ligament cells, which is a heterogeneous cell population, and includes progenitor cells that can differentiate into osteoblasts/cementoblasts. Mesenchymal stem cells (MSCs) can differentiate into various cells and can be used for periodontal regenerative therapy. Therefore, transplanted MSCs can be affected by humoral factors from periodontal ligament cells via the transcription factors or microRNAs (miRNAs) of MSCs. In addition, periostin (POSTN) is secreted from HPL cells and can regulate periodontal regeneration and homeostasis. To clarify the regulatory mechanism of humoral factors from periodontal ligament cells, we attempted to identify key genes, specifically microRNAs, involved in this process. METHODS: Human MSCs (hMSCs) were indirectly co-cultured with human periodontal ligament cells (HPL cells) and then evaluated for osteogenesis, undifferentiated MSCs markers, and miRNA profiles. Furthermore, hMSCs were indirectly co-cultured with HPL cells in the presence of anti-POSTN monoclonal antibody (anti-POSTN Ab) to block the effect of POSTN from HPL cells, and then evaluated for osteogenesis or undifferentiated MSC markers. Moreover, hMSCs showed alterations in miRNA expression or cultured with HPL were challenged with POSTN during osteogenesis, and cells were evaluated for osteogenesis or undifferentiated MSC markers. RESULTS: hMSCs co-cultured with HPL cells showed suppressed osteogenesis and characteristic expression of SOX11, an undifferentiated MSC marker, as well as miR-299-5p. Overexpression of miR-299-5p regulated osteogenesis and SOX11 expression as observed with indirect co-culture with HPL cells. Furthermore, MSCs co-cultured with HPL cells were recovered from the suppression of osteogenesis and SOX11 mRNA expression by anti-POSTN Ab. However, POSTN induced miR-299-5p and SOX11 expression, and enhanced osteogenesis. CONCLUSION: Humoral factors from HPL cells suppressed osteogenesis in hMSCs. The suppressive effect was mediated by miR-299-5p and SOX11 in hMSCs.

A tríade da engenharia tecidual aplicada na regeneração endodôntica: uma revisãode literatura / Tissue engineering triad applied in regenerative endodontics: a literature review

Introdução: A remoção do tecido pulpar, seguida da restauração do canal radicular com material sintético inerte, costuma ser um procedimento rotineiro na prática clínica para terapia endodôntica, porém esses materiais não substituem a função biológica, a vitali-dade e propriedades mecânicas do tecido original. Nesse contexto, a possibilidade de induzir a regeneração do complexo dentino-pulpar com o uso de células-tronco de origem dental tem sido cada vez mais estudada, e a expectativa é gerar o retorno da vitalidade pulpar e sua capacidade de reparo. Objetivo: Realizar uma revisão bibliográfica com o intuito de investigar a tríade formada por células tronco, fato-res de crescimento e arcabouço a fim de analisar a sua aplicabilidade na regeneração endodôntica. Materiais e métodos: Realizou-se uma revisão bibliográfica de estudos publicados nos últimos 5 anos (2015-2020) por meio da busca nas bases de dados: PubMed/Medline. Para a pesquisa foram utilizados os seguintes descritores: Células-tronco (Stem cells), Endodontia (Endodontics) e Regeneração endodôntica (endodonticregeneration). Após criteriosa filtragem, foram sele-cionados 25 artigos. Revisão de literatura: Pesquisas envolvendo a engenharia tecidual com o uso de células-tronco têm auxiliado a te-rapia regenerativa dos tecidos dentários, como o complexo dentino--pulpar. Para a completa restauração estrutural e funcional do dente são necessários um conjunto de elementos: as células-tronco; fatores de crescimento/diferenciação ou citocinas; fatores de migração/ho-ming e o microambiente: arcabouço (scaffold) e matriz extracelular. Conclusão: A regeneração do complexo dentino-pulpar por meio da engenharia tecidual baseada em fatores de crescimento e arcabou-ços é uma abordagem promissora para substituir estruturas dentárias danificadas e restaurar suas funções biológicas. No entanto, por se tratar de uma nova abordagem, seus estudos ainda são incipientes, necessitando de mais base científica para comprovar sua eficácia.

Introduction: The removal of pulp tissue followed by the restoration of the root canal with inert synthetic material is usually a routine procedure in clinical practice for endodontic therapy; however, these materials do not replace the biological function, the vitality, and mechanical properties of the original tissue. In this context, the possibility of inducing the regeneration of the dentin-pulp complex by using stem cells of dental origin has been increasingly studied, and the expectation is to generate the return of the pulp vitality and its repair capacity. Objective: To carry out a literature review to investigate the triad comprised by stem cells, growth factors, and framework to analyze its applicability in endodontic regeneration. Materials and methods: A bibliographic review of studies published in the last 5 years (2015-2020) was carried out by searching the databases: PubMed / Medline. he following descriptors were used: Stem cells, Endodontics, and Endodontic regeneration. After a careful filtering, 25 articles were selected. Literature review: Research involving tissue engineering with the use of stem cells has supported regenerative therapy of dental tissues, such as the dentin-pulp complex. For the complete structural and functional restoration of the tooth, a set of elements are needed: stem cells; growth/differentiation factors or cytokines; migration/homing factors, and the microenvironment: scaffold and extracellular matrix. Conclusion: The regeneration of the dentin-pulp complex through tissue engineering based on growth factors and frameworks is a promising approach to replace damaged dental structures and restore their biological functions. However, since it is a new approach, studies on this subject are still incipient and more scientific basis is necessary to prove its effectiveness.

Top-cited Articles in Regenerative Endodontics: A Bibliometric Analysis.

INTRODUCTION: Bibliometric analysis is a method for quantifying the research productivity, author performance, and manuscript impact. The citation count received by a scientific article is one of the indicators of its impact within a field. The purpose of this study was to identify the 100 top-cited articles published in regenerative endodontics and to analyze their main characteristics. METHODS: Thomson Reuters Web of Science was searched to retrieve the 100 most-cited articles in "regenerative endodontics" published from January 1991 to February 2018 in the category of "Dentistry, Oral Surgery and Medicine." Among the included top-cited articles, the following parameters were recorded and analyzed: journal name, authors, institution, country, publication title and year, number of citations and average citations, type of study, collaborations, and key words. The data were analyzed using SPSS version 19.0 (IBM Corp, Armonk, NY) and VOS viewer software (version 1.6.7; Leiden University Center for Science and Technology Studies, Leiden, Netherlands). RESULTS: Among the 100 top cited articles, the highest number of citations that an article received was 309. The top cited articles appeared in 14 different journals, and the Journal of Endodontics published the greatest number of these articles (66%). The majority of articles were published in the year 2014 (n = 17). The majority of articles originated from the United States (n = 51) with the most contribution from The University of Texas Health Science Center, San Antonio, TX. The most frequent first authors were Torabinejad (n = 4), Nosrat (n = 3), and Thibodeau (n = 3). In vitro studies were the most common study design (n = 29) followed by reviews (n = 21). "Regenerative endodontics" was the most frequently used key word. CONCLUSIONS: This bibliometric analysis reveals the progress and trend of research in the field of regenerative endodontics. The in vitro articles published in the field of regenerative endodontics had the highest number of citations and average citation rates.

Regenerative endodontics: a comprehensive review.

The European Society of Endodontology and the American Association for Endodontists have released position statements and clinical considerations for regenerative endodontics. There is increasing literature on this field since the initial reports of Iwaya et al. (Dental Traumatology, 17, 2001, 185) and Banchs & Trope (Journal of Endodontics, 30, 2004, 196). Endogenous stem cells from an induced periapical bleeding and scaffolds using blood clot, platelet rich plasma or platelet-rich fibrin have been utilized in regenerative endodontics. This approach has been described as a 'paradigm shift' and considered the first treatment option for immature teeth with pulp necrosis. There are three treatment outcomes of regenerative endodontics; (i) resolution of clinical signs and symptoms; (ii) further root maturation; and (iii) return of neurogenesis. It is known that results are variable for these objectives, and true regeneration of the pulp/dentine complex is not achieved. Repair derived primarily from the periodontal and osseous tissues has been shown histologically. It is hoped that with the concept of tissue engineering, namely stem cells, scaffolds and signalling molecules, that true pulp regeneration is an achievable goal. This review discusses current knowledge as well as future directions for regenerative endodontics. Patient-centred outcomes such as tooth discolouration and possibly more appointments with the potential for adverse effects needs to be discussed with patients and parents. Based on the classification of Cvek (Endodontics and Dental Traumatology, 8, 1992, 45), it is proposed that regenerative endodontics should be considered for teeth with incomplete root formation although teeth with near or complete root formation may be more suited for conventional endodontic therapy or MTA barrier techniques. However, much is still not known about clinical and biological aspects of regenerative endodontics.