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.

Effect of intracanal medicaments used in endodontic regeneration procedures on microhardness and chemical structure of dentin

OBJECTIVES: This study was performed to investigate the effects of different intracanal medicaments on chemical structure and microhardness of dentin. MATERIALS AND METHODS: Fifty human dentin discs were obtained from intact third molars and randomly assigned into two control groups and three treatment groups. The first control group received no treatment. The second control group (no medicament group) was irrigated with sodium hypochlorite (NaOCl), stored in humid environment for four weeks and then irrigated with ethylenediaminetetraacetic acid (EDTA). The three treatment groups were irrigated with NaOCl, treated for four weeks with either 1 g/mL triple antibiotic paste (TAP), 1 mg/mL methylcellulose-based triple antibiotic paste (DTAP), or calcium hydroxide [Ca(OH)2] and finally irrigated with EDTA. After treatment, one half of each dentin disc was subjected to Vickers microhardness (n = 10 per group) and the other half was used to evaluate the chemical structure (phosphate/amide I ratio) of treated dentin utilizing attenuated total reflection Fourier transform infrared spectroscopy (n = 5 per group). One-way ANOVA followed by Fisher's least significant difference were used for statistical analyses. RESULTS: Dentin discs treated with different intracanal medicaments and those treated with NaOCl + EDTA showed significant reduction in microhardness (p < 0.0001) and phosphate/amide I ratio (p < 0.05) compared to no treatment control dentin. Furthermore, dentin discs treated with TAP had significantly lower microhardness (p < 0.0001) and phosphate/amide I ratio (p < 0.0001) compared to all other groups. CONCLUSIONS: The use of DTAP or Ca(OH)2 medicaments during endodontic regeneration may cause significantly less microhardness reduction and superficial demineralization of dentin compared to the use of TAP.

Effect of intracanal medicaments used in endodontic regeneration procedures on microhardness and chemical structure of dentin

OBJECTIVES: This study was performed to investigate the effects of different intracanal medicaments on chemical structure and microhardness of dentin. MATERIALS AND METHODS: Fifty human dentin discs were obtained from intact third molars and randomly assigned into two control groups and three treatment groups. The first control group received no treatment. The second control group (no medicament group) was irrigated with sodium hypochlorite (NaOCl), stored in humid environment for four weeks and then irrigated with ethylenediaminetetraacetic acid (EDTA). The three treatment groups were irrigated with NaOCl, treated for four weeks with either 1 g/mL triple antibiotic paste (TAP), 1 mg/mL methylcellulose-based triple antibiotic paste (DTAP), or calcium hydroxide [Ca(OH)2] and finally irrigated with EDTA. After treatment, one half of each dentin disc was subjected to Vickers microhardness (n = 10 per group) and the other half was used to evaluate the chemical structure (phosphate/amide I ratio) of treated dentin utilizing attenuated total reflection Fourier transform infrared spectroscopy (n = 5 per group). One-way ANOVA followed by Fisher's least significant difference were used for statistical analyses. RESULTS: Dentin discs treated with different intracanal medicaments and those treated with NaOCl + EDTA showed significant reduction in microhardness (p < 0.0001) and phosphate/amide I ratio (p < 0.05) compared to no treatment control dentin. Furthermore, dentin discs treated with TAP had significantly lower microhardness (p < 0.0001) and phosphate/amide I ratio (p < 0.0001) compared to all other groups. CONCLUSIONS: The use of DTAP or Ca(OH)2 medicaments during endodontic regeneration may cause significantly less microhardness reduction and superficial demineralization of dentin compared to the use of TAP.