Mesenchymal stromal cells derived from exfoliated deciduous teeth express neuronal markers before differentiation induction

Abstract Objective: This study aimed to evaluate neuronal markers in stromal cells from human exfoliated deciduous teeth (SHED) and standardize the isolation and characterization of those cells. Methodology: Healthy primary teeth were collected from children. The cells were isolated by enzymatic digestion with collagenase. By following the International Society for Cell and Gene Therapy (ISCT) guidelines, SHED were characterized by flow cytometry and differentiated into osteogenic, adipogenic, and chondrogenic lineages. Colony-forming unit-fibroblasts (CFU-F) were performed to assess these cells' potential and efficiency. To clarify the neuronal potential of SHED, the expression of nestin and βIII-tubulin were examined by immunofluorescence and SOX1, SOX2, GFAP, and doublecortin (DCX), nestin, CD56, and CD146 by flow cytometry. Results: SHED showed mesenchymal stromal cells characteristics, such as adhesion to plastic, positive immunophenotypic profile for CD29, CD44, CD73, CD90, CD105, and CD166 markers, reduced expression for CD14, CD19, CD34, CD45, HLA-DR, and differentiation in three lineages confirmed by staining and gene expression for adipogenic differentiation. The average efficiency of colony formation was 16.69%. SHED expressed the neuronal markers nestin and βIII-tubulin; the fluorescent signal intensity was significantly higher in βIII-tubulin (p<0.0001) compared to nestin. Moreover, SHED expressed DCX, GFAP, nestin, SOX1, SOX2, CD56, CD146, and CD271. Therefore, SHED had a potential for neuronal lineage even without induction with culture medium and specific factors. Conclusion: SHEDs may be a new therapeutic strategy for regenerating and repairing neuronal cells and tissues.

Effect of dental tissue thickness on the measurement of oxygen saturation by two different pulse oximeters

Abstract This study aimed to evaluate the influence of different dental tissue thickness on the measurement of oxygen saturation (SpO2) levels in high (HP) and low (LP) blood perfusion by comparing the values obtained from two different pulse oximeters (POs) - BCI and Sense 10. Thirty freshly extracted human teeth had their crowns interposed between the POs and an optical simulator, which emulated the SpO2 and heart beats per minute (bpm) at HP (100% SpO2/75 bpm) and LP (86% SpO2/75 bpm) modes. Afterwards, the palatine/lingual surfaces of the dental crowns were worn with diamond drills. The reading of SpO2 was performed again using the POs alternately through the buccal surface of each dental crown. Data were analyzed by the Wilcoxon, Mann-Whitney and Kendall Tau-b tests (α=5%). The results showed significant difference at the HP and LP modes in the SpO2 readouts through the different dental thicknesses with the use of BCI, and at the LP mode with the use of Sense 10, which had a significant linear correlation (p<0.0001) and lower SpO2 readout values in relation to the increase of the dental thickness. Irrespective of tooth thickness, Sense 10 had significantly higher readout values (p<0.0001) than BCI at both perfusion modes. The interposition of different thicknesses of enamel and dentin influenced the POs measurement of SpO2, specially at the low perfusion mode. The POs were more accurate in SpO2 measurement when simulated perfusion levels were higher.

Resumo Este estudo avaliou a influência de diferentes espessuras de esmalte e dentina na medição dos níveis de saturação de oxigênio (SpO2) em alta (HP) e baixa (LP) perfusão sanguínea, comparando os valores obtidos em dois oxímetros de pulso (OPs) diferentes, BCI e Sense 10. Trinta dentes recém-extraídos de humanos tiveram suas coroas interpostas entre os OPs e um simulador óptico, que simulava a SpO2 e os batimentos cardíacos por minuto (bpm) nos modos de HP (100% SpO2 / 75 bpm) e LP (86% SpO2 / 75 bpm). Após, as superfícies palatinas / linguais dos dentes foram desgastadas com brocas de diamantadas. A leitura da SpO2 foi realizada novamente usando os dois OPs alternadamente através da face vestibular de cada coroa dental. Os dados foram analisados ​​pelos testes Wilcoxon, Mann-Whitney e Kendall Tau-b (α = 5%). Os resultados mostraram diferença significativa nos modos HP e LP nas leituras de SpO2 através das diferentes espessuras dentárias com o uso do BCI, e no modo LP com o uso do Sense 10, que teve correlação linear significativa (p <0,0001) e menores valores de leitura de SpO2 em relação ao aumento da espessura dentária. Independentemente da espessura do dente, o Sense 10 apresentou valores de leitura significativamente maiores (p <0,0001) do que o BCI em ambos os modos de perfusão. A interposição de diferentes espessuras de esmalte e dentina influenciaram a mensuração da SpO2 pelos OPs, especialmente no modo de baixa perfusão. Os POs foram mais precisos na mensuração da SpO2 quando os níveis simulados de perfusão foram maiores.

Microshear bond strength of universal adhesives to enamel and dentin: an eighteen-month in vitro study / Resistência de união ao microcisalhamento de adesivos universais ao esmalte e dentina: estudo in vitro de dezoito meses

Objective: The aim of this study was to evaluate the microshear bond strength of Universal adhesives to enamel and dentin after one week and eighteen months of water storage. Material and Methods: Fragments from the buccal surfaces of 80 bovine teeth were prepared (12x5x1.0 mm) and ground to obtain flat surfaces of enamel and dentin. Samples were randomly assigned to 8 experimental groups (n=10), according to four adhesive systems (Adper Single Bond Plus/control ­ not a Universal adhesive/ASB; Ambar Universal/AUN; Prime&Bond Active/PBA and Scotchbond Universal/SBU) and two water-storage times (one week and eighteen months after sample preparations). Adhesives were applied according to the manufacturers' instructions and molds were positioned over bonded surfaces. A flowable composite was poured into the molds to fill up their internal diameter and obtain resin cylinder (1.0mm height/0.7mm internal diameter) after light-curing. Bond strength was determined using a testing machine (0.5 mm/min) and data were statistically analyzed by two-way analysis of variance (ANOVA) and the post-hoc Tukey's test (alpha=0.05). Failure patterns were analyzed for all resin cylinder tested. Results: For enamel, differences among adhesives were observed only at 18 months, in which SBU produced lower bond strength values (15.9±3.0 MPa) than the others universal adhesives (AUN: 19.3±4.8 and PBA: 21.4±2.1 MPa) (p<0.05). For dentin, there were differences among adhesives only at 7 days, with PBA showing the highest bond strength (37.4±4.9 MPa) and ASB the lowest one (19.4±3.9 MPa) (p<0.05). Enamel and dentin bond strength of all adhesives decreased significantly after 18 months and reduction percentage varied from 36.9 to 52.4 for enamel and from 35.1 to 62.8 for dentin. Adhesive and mixed failures showed high incidences. Conclusion: Results suggested that adhesives presented differences among them depending on type of hard dental tissue and evaluation time. Enamel and dentin bond strengths of control and all universal adhesives tested were not stable, decreasing at eighteen months. (AU)

Objetivo: O objetivo deste estudo foi avaliar a resistência de união ao microcisalhamento de adesivos universais ao esmalte e dentina após uma semana e dezoito meses de armazenamento em água. Material e Métodos: Fragmentos da superfície vestibular de 80 dentes bovinos foram preparados (12x5x1,0 mm) até o obtenção de superfícies planas de esmalte e dentina. As amostras foram distribuídas aleatoriamente em 8 grupos experimentais (n=10), de acordo com quatro sistemas adesivos (Adper Single Bond Plus / controle - não universal; Ambar Universal; Prime & Bond Active e Scotchbond Universal) e dois tempos de armazenamento em água (uma semana e dezoito meses após o preparo das amostras). Os adesivos foram aplicados de acordo com as instruções dos fabricantes e as matrizes foram posicionadas sobre as superfícies aderidas. Um compósito fluido foi aplicado nas matrizes para preencher seu diâmetro interno e obter o cilindro do compósito por fotopolimeração (1,0 mm de altura / 0,7 mm de diâmetro interno). A resistência de união foi determinada em uma máquina universal de ensaios (0,5mm/min). Os dados foram analisados estatisticamente pela análise de variância dois fatores (ANOVA) e teste de Tukey (alfa 0,05). Resultados: Para o esmalte, foram obtidas diferenças apenas aos 18 meses, em que Scotchbond Universal produziu menor média de resistência de união do que os demais adesivos universais. Para dentina, houve diferenças entre os adesivos apenas aos 7 dias, com o Prime & Bond Active apresentando a maior resistência de união e o Adper Single Bond Plus a menor. Os resultados sugeriram que os adesivos apresentaram diferenças entre si dependendo do substrato e do tempo de avaliação. Conclusão: As resistências de união em esmalte e dentina do controle e de todos os adesivos universais testados não foram estáveis, diminuindo aos dezoito meses (AU)

Research progress on the methods of observation and analysis of dental bonding interfaces / 口腔疾病防治

@#Dental bonding technology and materials have been used widely in dentistry because of their excellent properties. The development of novel bonding technology and materials is constantly being performed to improve the effect of dental bonding restorations. Observation and analysis of the dental bonding interface is one of the most important methods for laboratory evaluation of bonding efficiency. This paper aims to review the methods of observation and analysis of dental bonding interfaces to provide a reference for the selection of evaluation methods in dental bonding research. The features of 6 methods, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), confocal laser scanning microscopy (CLSM), Raman spectroscopy (RS), optical coherence tomography (OCT) and atomic force microscopy (AFM), were described and summarized. Among these methods, SEM and TEM are used most often in the analysis of fine structures; CLSM and OCT are used for the acquisition of characteristic image signals, such as microleakage and exogenous and endogenous fluorescence; and RS and AFM can test chemical composition and mechanical properties.

Behavior of Mesenchymal Stem Cells Obtained From Dental Tissues: A Review of the Literature / Comportamiento de células mesenquimales obtenidas de tejidos dentales: Revisión de literatura

Abstract 20. The success of tissue engineering in combination with tissue regeneration depends on the behavior and cellular activity in the biological processes developed within a structure that functions as a support, better known as scaffolds, or directly at the site of the injury. The cell-cell and cell-biomaterial interaction are key factors for the induction of a specific cell behavior, together with the bioactive factors that allow the formation of the desired tissue. Mesenchymal Stem Cells (MSC) can be isolated from the umbilical cord and bone marrow; however, the behavior of Dental Pulp Stem Cells (DPSC) has been shown to have a high potential for the formation of bone tissue, and these cells have even been able to induce the process of angiogenesis. Advances in periodontal regeneration, dentin-pulp complex, and craniofacial bone defects through the induction of MSC obtained from tooth structures in in vitro-in vivo studies have permitted the obtaining of clinical evidence of the achievements obtained to date.

Resumen 24. El éxito de la ingeniería de tejidos en combinación con la regeneración de tejidos depende del comportamiento y la actividad celular en los procesos biológicos desarrollados dentro de una estructura que funciona como soporte mejor conocida como andamio o directamente en el sitio de la lesión. La interación célula-célula y célula-biomaterial son factores claves para la inducción a un comportamiento célular específico junto con factores bioactivos que permitan la formación del tejido deseado. Las células troncales mesenquimales (MSCs) pueden ser aisladas del cordón umbilical y de la medula ósea, sin embargo, el comportamiento de las células troncales de pulpa dental (DPSCs) han demostrado tener un alto potencial para la formación de tejido óseo e incluso han logrado inducir el proceso de angiogénesis. Avances en la regeneración periodontal, complejo dentino-pulpar y defectos óseos craneofaciales a travez de la inducción de MSCs obtenidas de estructuras de dientes en estudios in vitro-in vivo han permitido obtener evidencia clínica de los logros obtenidos hasta el momento.

Does cryopreservation affect the biological properties of stem cells from dental tissues? a systematic review

Abstract This systematic review evaluated if different cryopreservation protocols could affect biological properties (Cell survival rate (CSR), proliferation, differentiation, maintenance of stem cell markers) of stem cells obtained from dental tissues (DSC) post-thaw. An electronic search was carried out within PubMed and ISI Web Science by using specific keyword. Two independent reviewers read the titles and abstracts of all reports respecting predetermined inclusion/exclusion criteria. Data were extracted considering the biological properties of previously cryopreserved DSCs and previously cryopreserved dental tissues. DSCs cryopreserved as soon as possible after their isolation presents a CSR quite similar to the non-cryopreserved DSC. Dimethyl sulfoxide (DMSO) [10%] showed good results related to cell recovery post-thaw to cryopreserve cells and tissues for periods of up to 2 years. The cryopreservation of DSC in a mechanical freezer (-80°C) allows the recovery of stem cells post-thaw. The facilities producing magnetic field (MF), demand a lower concentration of cryoprotectant, but their use is not dispensable. It is possible to isolate and cryopreserve dental pulp stem cell (DPSC) from healthy and diseased vital teeth. Cryopreservation of dental tissues for late DSC isolation, combined with MF dispensability, could be valuable to reduce costs and improve the logistics to develop teeth banks.

Resumo Essa revisão sistemática avaliou se diferentes protocolos de criopreservação podem afetar as propriedades biológicas (taxa de sobrevivência celular, proliferação, diferenciação, manutenção dos marcadores de superfície) de células-tronco isoladas de tecidos dentais (DSC) após o descongelamento. Uma busca eletrônica foi realizada no PubMed e no ISI Web of Science utilizando palavras-chave específicas. Dois revisores independentes avaliaram os títulos e resumos de todos os estudos respeitando critérios de inclusão e exclusão previamente determinados. Os dados foram extraídos considerando as propriedades biológicas de DSC, e DSC isoladas de tecidos previamente criopreservados. DSC criopreservadas logo após seu isolamento apresentaram propriedades biológicas muito semelhantes às observadas em DSC não criopreservadas. Dimetil sulfóxido (DMSO) [10%] demonstrou bons resultados relacionados com a recuperação celular após descongelamento de células e tecidos, por períodos de até 2 anos. A criopreservação de DSC em freezer mecânico (-80 °C) permite a recuperação de células-tronco pós-descongelação. A utilização de freezer com campo magnético (MF), proporciona a utilização de uma menor concentração de crioprotector, mas a sua utilização não é dispensável. É possível isolar e criopreservar e criopreservar células-tronco da polpa dental (DPSC) de dentes vitais saudáveis e doentes. Criopreservação de tecidos dentais após o isolamento de DSC, combinados com MF, podem ser valiosas estratégias para reduzir custos e melhorar a logística no desenvolvimento de bancos de dentes.

Descripción radiográfica de postes de titanio y de fibra de vidrio, cementados en premolares humanos sometidos in vitro a altas temperaturas con fines forenses / Radiographic description of titanium and fiberglass posts cemented in human premolars subjected to high temperatures in vitro for forensic purposes

Introducción: durante el proceso de identificación forense de cadáveres y restos humanos quemados, carbonizados o incinerados, el análisis de los materiales empleados en los diferentes tratamientos odontológicos se constituye en un marcador fehaciente para lograr una identificación positiva. El objetivo de este trabajo fue describir los cambios radiográficos de postes de titanio y de fibra de vidrio cementados, en premolares humanos sometidos a altas temperaturas con fines forenses. Métodos: estudio pseudo-experimental in vitro que observó los cambios radiográficos de los tejidos dentales (esmalte, dentina y cemento), de los materiales de uso endodóncico gutapercha (Wave One® de Dentsply Maillefer®), material de obturación (Top Seal® de Dentsply Maillefer®), material de cementación de los postes (Relyx TM ARC de 3M ESPE®) y de los postes de titanio (Tenax® Endodontic Post System de Coltene®) y fibra de vidrio (Tenax® Fiber Trans de Coltene®) en 30 dientes humanos, sometidos a cinco rangos de temperatura 200, 400, 600, 800 y 1000ºC. Resultados: los tejidos y los materiales dentales estudiados presentan gran resistencia a las altas temperaturas, sin variar considerablemente su macro-estructura (fisuras, grietas, fracturas y fragmentación), de tal manera que los cambios físicos pueden identificarse a través de radiografía convencional, y asociarse a cada rango de temperatura específico. Conclusiones: los postes cementados en premolares humanos presentan gran resistencia a la acción de altas temperaturas, razón por la cual pueden ser visualizados a través de radiografía convencional, contribuyendo con el proceso de identificación y documentación de la necropsia médico-legal de un cadáver o restos humanos que hayan resultado quemados, incinerados o carbonizados

IIntroduction: during the process of forensic identification of corpses and burnt, carbonized, or incinerated human remains, the analysis of materials used in dental treatments is a reliable marker for accurate identification. The objective of this study was to describe the radiographic changes of titanium and fiberglass posts cemented in human premolars subjected to high temperatures for forensic purposes. Methods: this was a pseudo-experimental in vitro study to observe the radiographic changes of dental tissues (enamel, dentin, and cement) and the following endodontic materials: gutta-percha (Wave One® by Dentsply Maillefer®), obturation material (Top Seal® by Dentsply Maillefer®), post cementation material (Relyx TM ARC by 3M ESPE®), titanium posts (Tenax® Endodontic Post System by Coltene®), and fiberglass posts (Tenax® Fiber Trans by Coltene®) in 30 human teeth subject to five temperature ranges: 200, 400, 600, 800, and 1000° C. Results: the studied dental tissues and materials are highly resistant to high temperatures without significantly changing their macrostructure (fissures, cracks, fractures, and fragmentation), in such a way that the physical changes can be identified through conventional radiography and associated with each specific temperature range. Conclusions: posts cemented in human premolars have great resistance to the action of high temperatures, so they can be observed through conventional radiography thus contributing to the process of identification and documentation of the medico-legal autopsy of a corpse or human remains that have been burned, incinerated, or carbonized

Análisis a través de microscopía electrónica de barrido de dos dientes con tratamiento endodóncico sometidos a altas temperaturas: estudio piloto / Scanning electron microscopy analysis of two endodontically treated teeth subjected to high temperatures: a pilot study

Introducción: el objetivo fue describir los cambios físico-químicos que ocurren en los tejidos y materiales dentales empleados en un tratamiento endodóncico convencional, al ser sometidos a altas temperaturas, a través de microscopía electrónica de barrido (MEB). Métodos: in vitro, se sometieron dos dientes premolares humanos a 200 y 400 ºC respectivamente, con el fin de estandarizar una técnica para la observación de los cambios físicos y químicos en los tejidos dentales (esmalte y dentina) y de los materiales de uso odontológico empleados comúnmente en endodoncia (gutapercha y cemento endodóncico a base de resina epóxica). Resultados: tanto los tejidos como los materiales dentales observados en este estudio piloto, presentaron gran resistencia a las altas temperaturas sin variar considerablemente su macroestructura, de tal manera que los cambios físicos (estabilidad dimensional, fisuras, grietas, fracturas, textura, carbonización) y químicos (elementos químicos constituyentes) pueden llegar a ser identificables y asociarse a cada rango de temperatura específico através del análisis MEB y espectrofotométrico. Conclusiones: los tejidos y los materiales dentales presentan gran resistencia a la acciónde altas temperaturas sin alterar su macroestructura de forma significativa. Del mismo modo, presentan cambios físicos y químicos que pueden contribuir con el proceso de identificación de un cadáver o restos humanos quemados, incinerados o carbonizados.

Introduction: the objective of this study was to describe the physicochemical changes occurring in dental tissues andmaterials used in a conventional endodontic treatment when subjected to high temperatures, by means of scanning electron microscopy(SEM) Methods: in vitro, two human premolar teeth were subjected to temperatures of 200°C and 400°C respectively, with the purpose ofstandardizing a technique for the observation of physical and chemical changes in dental tissues (enamel and dentin) and dental materialscommonly used in endodontic treatment (root canal gutta-percha and epoxy resin-based endodontic cement). Results: both the tissues and the dental materials analyzed in this pilot study presented great resistance to high temperatures without significantly changing their macrostructure; therefore, the physical changes (dimensional stability, cracks, crevices, fractures, texture, carbonization) and the chemical ones (constituent chemical elements) may turn out to be identifiable and associated with each specific temperature range by means of SEM and spectrophotometric analysis. Conclusions: dental tissues and materials display great resistance to the action of high temperatures, without significantly altering their macrostructure. Similarly, they experience physical and chemical changes that may contribute to theprocess of identification of a corpse or human remains that have been burned, incinerated or charred.