Clinical implementation of comprehending dentin on a microscopic level

SUMMARY: The aim of the present in vitro study is to visualize dentin to get an in-depth knowledge of the nature of dentin that could provide useful information regarding conditioning dentinal substrate when treating dentinal lesions. Forty-nine extracted human third molars were obtained and prepared to produce artificial dentinal lesions through demineralizing with acetic acid for 7 and 14 days, or lactic acid for 7 days. The teeth were divided into groups and treated with either NaOCl, pepsin, trypsin, or phosphoric acid. To obtain information on the morphology of the treated dentinal surfaces, all samples were visualized under high resolution field emission scanning electron microscope. With high magnification reaching x50000 dentin was clearly visualized together with its constitutes. The effect of various demineralization approaches and various treatment protocols were demonstrated clearly. The relationship between the conditioning procedure steps and the subsequent bond strength was discussed. To our best knowledge, there is no previous clear highly magnified scanning electron microscope images for dentin, and dentinal components and constitutes with and without various treatments. The current in vitro study suggests the complexity nature of dentin as a substrate that should be treated carefully especially with technique sensitive procedures such as adhesive restorations.

El objetivo del presente estudio in vitro fue visualizar la dentina para obtener un conocimiento completo de la naturaleza de ella lo que podría proporcionar información útil sobre el acondicionamiento del sustrato dentinario en el tratamiento de lesiones dentinarias. Se obtuvieron 49 terceros molares humanos extraídos y se prepararon para producir lesiones dentinales artificiales mediante desmineralización con ácido acético por 7 y 14 días, o ácido láctico por 7 días. Los dientes se dividieron en grupos y se trataron con NaOCl, pepsina, tripsina o ácido fosfórico. Para obtener información sobre la morfología de las superficies dentinarias tratadas, todas las muestras se visualizaron bajo un microscopio electrónico de barrido de emisión de campo de alta resolución. Con un gran aumento que alcanzó x50000, la dentina se visualizó claramente junto con sus componentes. Se demostró el efecto de varios enfoques de desmineralización y varios protocolos de tratamiento. Se discutió la relación entre los pasos del procedimiento de acondicionamiento y la subsiguiente fuerza de unión. Hasta donde sabemos, no hay imágenes claras previas de microscopio electrónico de barrido altamente ampliadas para la dentina y los componentes y constituyentes de la dentina con y sin diferentes tratamientos. El estudio in vitro actual sugiere la naturaleza compleja de la dentina como sustrato que debe tratarse con cuidado, especialmente en los procedimientos sensibles a la técnica, tal como las restauraciones adhesivas.

Effects of using different root canal sealers and protocols for cleaning intraradicular dentin on the bond strength of a composite resin used to reinforce weakened roots / Efectos del uso de diferentes selladores de conductos radiculares y protocolos para limpiar la dentina intrarradicular sobre la fuerza de unión de una resina compuesta utilizada para reforzar raíces debilitadas

Background: This study evaluated the effects of using different root canal sealers and protocols for cleaning intraradicular dentin on the bond strength of a composite resin used to reinforce weakened roots. Material and Methods: Sixty-four roots of extracted human maxillary canines were weakened, prepared and filled with two different endodontic sealers (Endofill and AH Plus). In half of the sample, set aside for each respective sealer, excess filling material was cleaned. In the other half, the weakened areas were not cleaned, and the excess of sealer was spread on the intraradicular dentin. Intentionally worn areas inside each root were restored with a microhybrid light-cure composite resin (Z100) to reinforce them, with and without acid etching. Prefabricated metal posts were fixed with a dual resin cement (RelyX ARC), and the specimens were submitted to a pull-out test. Statistical analysis was performed by means of Shapiro-Wilk, analysis of variance (one-way ANOVA) and Tukey-Kramer tests (p<0.05). Results: The groups filled with Endofill (GI, GII, GIII, GIV) had the lowest bond strength values, which were similar among each other (p>0.05).The greatest bond strength values were observed in roots filled with AH Plus (GV, GVI, GVII, GVIII), mainly without cleaning of the weakened areas, and followed by acid etching (GVII), and also with cleaning of the weakened areas, however, with no acid etching (GVI) (p<0.05). Conclusion: The greatest bond strength values were observed in roots filled with AH Plus; (1) without cleaning of the weakened areas and with acid etching, and; (2) with cleaning of the weakened areas, but without acid etching.

Antecedentes: este estudio evaluó los efectos del uso de diferentes selladores de conductos radiculares y protocolos para limpiar la dentina intrarradicular sobre la fuerza de unión de una resina compuesta utilizada para reforzar las raíces debilitadas. Material y Métodos: Sesenta y cuatro raíces de caninos maxilares humanos extraídos fueron debilitadas, preparadas y rellenadas con dos selladores endodónticos diferentes (Endofill y AH Plus). En la mitad de la muestra, reservada para cada sellador respectivo, se limpió el exceso de material de relleno. En la otra mitad, las áreas debilitadas no se limpiaron y el exceso de sellador se esparció sobre la dentina intrarradicular. Las áreas desgastadas intencionalmente dentro de cada raíz se restauraron con una resina compuesta fotopolimerizable microhíbrida (Z100) para reforzarlas, con y sin grabado ácido. Los postes metálicos prefabricados se fijaron con un cemento de resina dual (RelyX ARC) y los especímenes se sometieron a una prueba de extracción. El análisis estadístico se realizó mediante Shapiro-Wilk, análisis de varianza (ANOVA de una vía) y pruebas de Tukey-Kramer (p<0,05). Resultados: Los grupos rellenos con Endofill (GI, GII, GIII, GIV) presentaron los valores más bajos de fuerza de unión, los cuales fueron similares entre sí (p>0,05). Los mayores valores de fuerza de unión se observaron en raíces rellenas con AH Plus (GV, GVI, GVII, GVIII), principalmente sin limpieza de las áreas debilitadas, seguido de grabado ácido (GVII), y también con limpieza de las áreas debilitadas aunque sin grabado ácido (GVI) (p<0.05). Conclusión: Los mayores valores de fuerza de unión se observaron en las raíces rellenas con AH Plus; (1) sin limpieza de las áreas debilitadas y con grabado ácido, y; (2) con limpieza de las áreas debilitadas, pero sin grabado ácido.

Uso efectivo de los adhesivos de octava generación / Effective use of eighth generation adhesives

Introducción: se realizó una revisión bibliográfica con el objetivo de conocer, analizar y comparar los diferentes tipos de adhesivos de octava generación que se encuentran en el mercado y la diferencia que existe entre cada uno. Los adhesivos universales han demostrado mejoras en su resistencia, sobre todo en las técnicas de aplicación y en las propiedades de estos materiales, al mejorar la fuerza adhesiva para que el odontólogo pueda brindar tratamientos restaurativos exitosos. Objetivo: conocer, analizar y comparar los diferentes tipos de adhe- sivos de la octava generación empleados en odontología. Material y métodos: se realizó una búsqueda en las bases de datos electrónicas PubMed, BVS, Redalyc y ScienceDirect. Se utilizaron 32 artículos que cumplieron con los criterios predeterminados y la especificidad reque- rida para la pregunta de investigación. Conclusiones: se demostró que la tecnología cada día avanza, sobre todo en el área de los adhesivos, ya que éstos son de mucha utilidad en el día a día del odontólogo; es importante conocer cada uno de éstos, puesto que es un poco complejo seleccionar el correcto, mas no el uso. En la actualidad, existen diversas opciones por las que el odontólogo puede optar, es por ello que el pro- fesional debe estar capacitado sobre cada una de las diferentes marcas existentes y, de acuerdo al tratamiento, debe elegir cuál es mejor utilizar en una rehabilitación. Es importante para el odontólogo conocer estos materiales, ya que esto lo beneficiará al momento de llevar un plan de tratamiento restaurador (AU)

Introduction: a bibliographic review was carried out to learn about, analyze, and compare the different types of eighth-generation adhesives on the market and the difference between each one. Universal adhesives have demonstrated improvements in their resistance, especially in the application techniques and properties of these materials, improving the adhesive strength so that the dentist can provide successful restorative treatments. Objective: to know, analyze and compare the different types of eighth-generation adhesives used in dentistry. Material and methods: a search was made of the following electronic databases: PubMed, BVS, Redalyc, ScienceDirect. Finally, 32 articles that met the predetermined criteria and the specificity required for the research question were used. Conclusions: it was demonstrated that technology is advancing every day, especially in the area of adhesives since these are very useful in the daily life of the dentist. It is important to know each one of these since it is a little complex at the moment of selecting the correct one, but not the use. Currently, there are several options that the dentist can choose, which is why the professional must be trained on each of the various existing brands and according to the treatment which is the best to use at the time of rehabilitation. The dentist needs to know these materials since they will benefit him/her when carrying out a restorative treatment plan (AU)

Potencial remineralizante del fluoruro diamino de plata al 38% en dentina de dientes temporales afectada por caries / Remineralizing potential of 38% silver diamine fluoride in dentin affected by dental caries

Introducción: la caries es una enfermedad compleja que afecta a cualquier edad. La prevalencia es mayor en la primera dentición, sobre todo en población con baja percepción económica. El fluoruro diamino de plata (FDP) al 38% ha sido utilizado como una alter- nativa de tratamiento para esta enfermedad. Funciona como una solución remineralizante y cariostática. Objetivo: evaluar el efecto remineralizante del FDP al 38% en dentina afectada por lesiones de caries en molares temporales. Material y métodos: estudio clínico, epidemiológico, descriptivo, longitudinal y experimental. Se llevó a cabo en molares de primera dentición de niños de tres a cinco años de edad. Los niños seleccionados tenían molares con lesiones cariosas dentinarias, Pitts las denomina D3. No se incluyeron niños con dientes que presentaron patologías pulpares irreversibles. La aplicación del FDP al 38% la efectuó un operador entrenado para esta finalidad. Se utilizaron los criterios de Nyvad para determinar el grado de dureza de la dentina y con ello deducir su remineraliza- ción. Se observó la permanencia de la remineralización efectuada por un periodo de cinco meses. Resultado y conclusión: el FDP es un compuesto eficaz en 91% de los casos en un periodo de cinco meses o más (AU)

Introduction: dental caries is a complex disease that affects any age. The prevalence is higher in primary dentition, especially in a population with low economic perception. 38% silver diamine fluoride (FDP) has been used as an alternative treatment for this disease. It works as a remineralizing and cariostatic solution. Objective: to evaluate the remineralizing effect of 38% FDP on dentin affected by dental caries, in temporary molars. Material and methods: clinical, epidemiological, descriptive, longitudinal and experimental study. It was carried out in temporary molars of children between three and five years of age. The selected children presented molars with dental carious lesions, Pitts calls them D3. Children with teeth that presented irreversible pulp pathologies were not included. The application of the FDP to 38% was carried out by an operator trained for this purpose. The Nyvad criteria were used to determine the degree of hardness of the dentin and thereby deduce its remineralization. The permanence of the remineralization carried out was observed for a period of five months. Result and conclusion: the FDP is an effective compound in 91% of the cases, in a period of five months or more (AU)

Comparación de la fuerza de adhesión a dentina de cementos de autograbado vs grabado total / Comparison of bond strength to dentin of self-etching cements vs total etching

Los sistemas cementantes han mejorado notablemente, los objetivos que persiguen los nuevos cementos es que la adhesión sea duradera y conseguir siempre que sea posible una interface cerrada con un sellado perfecto. Se han podido desarrollar nuevas técnicas y nuevos materiales de cementación que han ido perfeccionando la unión del material restaurador al diente. En el presente estudio se compara la fuerza de adhesión a dentina de cementos de autograbado y cementos de grabado total para comprobar los efectos positivos en el grabado de la dentina. Para el estudio se utilizaron dos cementos a base de resina (RelyX U200 Clicker 3M y RelyX Ultimate 3M). Se encapsularon 40 molares en acrílico en dos grupos de 20 muestras para la aplicación de dos sistemas cementantes de autograbado (grupo 1) y de grabado total (grupo 2), respectivamente, se desgastaron hasta descubrir la dentina; siguiendo las especificaciones del fabricante se colocó el cemento en cada grupo, y después se sometieron a pruebas de cizalla en una máquina de ensayo universal Instron. La medida expresada en megapascales (MPa) fue: grupo 1 = 7.5569 y grupo 2 = 12.6444. En este caso fueron analizados dos grupos, tomándose la primera significancia bilateral. Se realiza la prueba en t de Student, con 95% de intervalo de confianza en la diferencia, demostrando así que el cemento RelyX Ultimate 3M tiene mayor fuerza de adhesión que el cemento RelyX U200 Clicker 3M. Nuestra investigación fue factible y llegamos a nuestro propósito, en el cual comprobamos la mayor adhesión de cementos de grabado total, los cuales son sometidos a un previo tratamiento del diente (AU)

Adhesión a dentina parte I: características del sustrato y sistemas adhesivos / Dentin bonding part I: substrate characteristics and bonding systems

La Odontología Restauradora contemporánea no puede concebirse sin la adhesión de los materiales restauradores a las estructuras dentarias. En mu-chos procedimientos restauradores, no sólo el esmal-te sino también la dentina se encuentra involucrada, por lo tanto, la adhesión a esta última juega un rol cla-ve en el éxito clínico. No obstante, todavía supone un gran desafío lograr una adhesión estable y predeci-ble en el tiempo. El propósito del presente artículo es analizar las características principales de la dentina como sustrato adhesivo y describir los sistemas ad-hesivos actuales y sus mecanismos de acción (AU)

Contemporary Restorative Dentistry cannot be conceived without the adhesion of restorative materials to dental structures. In many restorative procedures not only the enamel, but also the dentin is involved, therefore dentin bonding plays a key role in their success. However, it is still a great challenge to achieve stable and predictable dentin bonding over time. The aim of this article is to analyze the main characteristics of dentin as an adhesive substrate and to describe current adhesive systems and their bonding mechanisms (AU)

Adhesión a dentina part II: estrategias para optimizar la adhesión a dentina y protocolos adhesivos / Dentin bonding part II: strategies to optimize dentin bonding and adhesive protocols

La adhesión a dentina con sistemas adhesivos polimé-ricos representa un desafío que surge de la necesi-dad de vincular un sustrato dentario heterogéneo y variable con materiales que presentan todavía cier-tos aspectos a atender para poder conseguir el máxi-mo desempeño. El propósito del presente artículo es evaluar algunas de las estrategias propuestas para mejorar la adhesión a dentina, y sugerir un protocolo de trabajo con los diferentes tipos de sistemas adhesivos (AU)

Dentin bonding with polymeric adhesive systems represents a challenge that arises from the need to link a heterogeneous and variable dental substrate with materials that still have certain aspects to be addressed in order to achieve maximum performance. The aim of this article is to evaluate some of the proposed strategies to improve dentin bonding and to suggest a protocol for each different type of bonding systems (AU)

Biomateriales que inducen la remineralización del esmalte dental y dentina / Biomaterials that induce remineralization of the dentin and enamel surface

Desde los sesentas, con la invención del vidrio bioactivo, los tratamientos de remineralización se han popularizado entre los cirujanos dentistas y su utilización es cada vez mayor; la remineralización, en conjunto con las adecuadas medidas de higiene preventiva, representa uno de los mejores abordajes mínimamente invasivos y a un costo comparativamente bajo. Este estudio documental tiene por objetivo establecer una mejor comprensión del uso clínico de los biomateriales que inducen la remineralización de la superficie del esmalte dental y dentina. Se realizó una exploración utilizando motores de búsqueda (bases de datos en PubMed, Medigraphic, y Science Direct). El proceso de localización de los estudios relevantes se efectuó introduciendo palabras clave como: silicatos de calcio, fosfopéptidos de caseína-fosfato de calcio amorfo, remineralización, esmalte y dentina, incluyéndose en el procedimiento artículos de antigüedad no superior a siete años, en español e inglés, publicados en revistas científicas aprobadas por pares.Actualmente, no es posible remineralizar del todo la estructura dentaria, por lo cual, en un futuro cercano, los esfuerzos de la odontología de remineralización deben apuntar al desarrollo de agentes biomiméticos inteligentes que restauren al cien por ciento la estructura dental perdida (AU)

Since the sixties, with the invention of bioactive glass, remineralization treatments have become popular among dental surgeons. Their usage is increasing; remineralization, in conjunction with appropriate preventive hygiene measures, represents one of the best minimally invasive treatments at a relatively low cost. This documentary study aims to establish a better understanding of the clinical use of biomaterials that induce remineralization of the surface of teeth enamel and dentin. A search was conducted using search engines (PubMed and Medigraphic databases, and Science Direct). The search process for the relevant studies was carried out by introducing keywords such as calcium silicates, phosphopeptides of amorphous calcium casein-phosphate, remineralization, enamel and dentin, including in the search articles no older than seven years in Spanish and English published in scientific reviewed journals. Currently, it is not possible to completely remineralize the dentary structure so, in the near future, remineralization dentistry efforts should aim to develop (AU)

Contaminación de la dentina con diferentes técnicas de secado / Contamination of dentin with different drying techniques

El secado es uno de los factores clave para lograr una adhesión micromecánica exitosa en la dentina con los sistemas adhesivos de grabado independiente. El objetivo de este trabajo fue comparar los residuos remanentes luego de cuatro procedimientos diferentes de secado en preparaciones ex vivo en dentina. Se utilizaron cinco terceros molares ex-vivo, en cada uno de los cuales se realizó una preparación dentinaria en piso y paredes con al menos un socavado. Las unidades experimentales fueron almacenadas en solución fisiológica durante 7 días. Las distintas técnicas de secado (G1- G8) se aplicaron, luego de que las preparaciones fueron tratadas con gel de ácido fosfórico al 37% (Blue Gel etch Megadental) durante 15s y lavadas con jeringa y agua a presión durante 15s (Técnica de Grabado Ácido o TGA), de la siguiente manera: algodón común (Condesa) (G1), papel tisú (Achiss) cortado a mano (G2) y con tijera (G3), esponja (Sharpys) (G4), papel tisú (Simplicity) cortado a mano (G5)(AU)

Is it necessary to pre-treat Dentine before GIC Restorations? Evidence from an in Vitro Study / É necessário pré tratar a dentina antes das restaurações de CIV? Evidência de um estudo in vitro

ABSTRACT The aim of this study was to assess the influence of differentpretreatmentapproaches on glass ionomer cement (GIC)bond strength (BS) to dentine. Sixty bovine incisors wereallocated into six groups according to substrate - sound orcariesaffecteddentine; and substrate pretreatmentapproach -no conditioning (control), polyacrylic acid for 10 s andphosphoric acid for 7 s. Teeth in the cariesaffecteddentinegroup were previously submitted to cariogenic pHcyclingchallenge. After dentine pretreatment,according to experi mentalgroups, polyethylene tubes were placed on flat dentinesurfaces and filled with GIC. Teeth were stored in distilledwater for 24 h at 37 °C and then submitted to microshear test(0.5 mm/min). Failure pattern analysis was performed understereomicroscope (400x). Data were analysed using twowayANOVA and Tukey's test (α=5%). Statistically significantdifferences were found for the pretreatmentapproach,regardless of substrate (p<0.001). The polyacrylic acid groupand control group had similar BS values, and were both betterthan the phosphoric acid group. In general, GIC had betterbonding performance in sound dentine than in cariesaffecteddentine. In conclusion, dentine pretreatmentwith polyacrylicacid did not improve the performance of GIC restoration onclinically relevant substrates.

RESUMO O objetivo deste estudo foi avaliar a influência de diferentesprétratamentosna resistência de união (RU) de cimentos deionômero de vidro (CIV) a dentina. Sessenta incisivos bovinosforam alocados em 6 grupos de acordo com o substrato -hígido ou cariado; e com a abordagem de prétratamento-sem condicionamento (controle), ácido poliacrílico por 10 s, eácido fosfórico por 7 s. Os dentes pertencentes aos grupos dedentina cariada foram previamente submetidos ao desafiocariogênico por meio da ciclagem de pH. Após o prétratamentoda dentina, de acordo com os grupos experimentais,tubos de polietileno foram colocados sobre superfícies planas dedentina e preenchidos com CIV. Os dentes foram armazenadosem água destilada por 24 h a 37°C e então submetidos ao testede microcisalhamento (0,5 mm/min). A análise do padrão defratura foi realizada em estereomicroscópio (400x). Os dadosobtidos foram analisados usando ANOVA de dois fatores e testede Tukey (α=5%). Diferença estatisticamente significante foiencontrada para as diferentes abordagens de prétratamento,independente do substrato (pp<0,001). Aplicação de ácidopoliacrílico resultou em valores de RU similares aos do grupocontrole. Entretanto, ambos os grupos mostraram um melhordesempenho quando comparado a aplicação de ácidofosfórico. De forma geral, CIV apresentou melho5 desempenhoadesivo em dentina sadia quando comparada a dentinacariada. Em conclusão, o prétratamentoem dentina comácido poliacrílico não melhora o desempenho das restauraçõesde CIV em substratos clinicamente relevantes.

Antimicrobial activity of intracanal dressings composed by natural products associated to chlorhexidine and its influence on dentinal colour change / Avaliação da ação antimicrobiana de medicações intracanais à base de produtos fitoterápicos associados à clorexidina e sua influência na alteração de cor da estrutura dentinária

Purpose: evaluate the antimicrobial activity of intracanal dressings and their influence on dentinal colour changes. Material and methods: eighty single-rooted human extracted teeth were decoronated and divided into eight groups (n=10) according to intracanal dressing protocols inserted into the root canals: G1­distilled water (DW); G2­2% chlorhexidine gel (CHX); G3­calcium hydroxide (Ca[OH]2)+DW; G4­grape seed extract (GSE)+DW; G5­ginger extract (GE)+DW; G6­Ca(OH)2+CHX; G7­GSE+CHX; and G8­GE+CHX. The antimicrobial activity was evaluated by colony-forming units (CFUs) counting and dentinal colour changes was evaluated by digital spectrophotometry. Data were statistically analysed by One-way ANOVA followed by Tukey´s post hoc test (antimicrobial evaluation) and non-parametric Wilcoxon followed by the Mann- Whitney-U test (colour change evaluation) (α=0.05). Results: the highest bacterial reduction was observed in groups 4, 6, 7 and 8, with no significant difference between them (p<0.05). Groups 4 and 7 showed the highest medians of dentinal colour change (p<0.05). Conclusion: the addition of CHX improved the antimicrobial activity of GE-based intracanal dressing, with no effect in GSE-based intracanal dressing; moreover, these protocols induced significant dentinal colour changes. (AU)

Objetivo: avaliar a atividade antimicrobiana de medicações intracanais e sua influência na alteração da cor dentinária. Materiais e métodos: oitenta dentes humanos extraídos unirradiculares foram seccionados e divididos em oito grupos (n = 10), de acordo com os protocolos de medicação intracanal inseridos nos canais radiculares: água destilada G1 (DW); G2-2% de gel de clorexidina (CHX); hidróxido de cálcio G3 ­ (Ca [OH] 2) + DW; extrato de semente de uva G4 (GSE) + DW; extrato de gengibre G5 (GE) + DW; G6- Ca (OH) 2 + CHX; G7 ­ GSE + CHX; e G8-GE + CHX. A atividade antimicrobiana foi avaliada por contagem de unidades formadoras de colônias (UFCs) e as alterações de cor dentinária foram avaliadas por espectrofotometria digital. Os dados foram analisados estatisticamente por ANOVA one-way, seguida pelo teste post hoc de Tukey (avaliação antimicrobiana) e Wilcoxon não paramétrico, seguido pelo teste de Mann- Whitney-U (avaliação da mudança de cor) (α = 0,05). Resultados: a maior redução bacteriana foi observada nos grupos 4, 6, 7 e 8, sem diferença significativa entre eles (p < 0,05). Os grupos 4 e 7 apresentaram as maiores medianas da alteração da cor dentinária (p < 0,05). Conclusão: a adição de CHX melhorou a atividade antimicrobiana da medicação intracanal baseado em GE, sem efeito na medicação intracanal baseado em GSE; além disso, esses protocolos induziram alterações significativas na cor dentinária.(AU)

Adhesive resistance of a copaiba oil-based dentin biomodifier

Abstract This study analyzed the effect of prior application of copaiba oil (CO) emulsions as a dentin cleaning substance on microleakage and microtensile adhesive strength. Twenty-five premolars and sixty-four molars were used for microleakage and microtensile assays. For the microleakage assays, specimens with standard class V cavities were divided (n = 5), according to the tested CO emulsions: CO10%X, CO10%Y, and CO10%Z, as well as chlorhexidine 2% (CHX) and distilled water (DW), as positive and negative controls, respectively. Restorations were performed using the Adper Single Bond® and/or Clearfil SE Bond® systems. Cervical, occlusal, distal and mesial sections were assessed for tracer penetration degree at the composite/tooth interface. For the microtensile assay, healthy molars were divided into sixteen groups, in which artificial caries were induced in half of the groups. Dentin surfaces were treated with CO10%X and CO10%Y, CHX and DW. Microtensile bond strength was measured by fixing each sample to the plate of a universal testing machine operated at a speed of 0.5 mm/minute until failure. Dentin treated with CO10%X showed a lower infiltration rate than dentin treated with the other CO emulsions, CHX2% and DW. According to the microtensile assay, both healthy and affected dentin treated with CO10%X and Adper Single Bond® adhesive system presented higher adhesive strength. CO emulsion, used as a dentin biomodifier, interfered positively in microleakage and improved adhesive strength after acid etching in the Adper Single Bond® adhesive system, or before applying the Clearfil SE Bond® self-etching system.

Evaluation of dentinogenesis inducer biomaterials: an in vivo study

Abstract When exposure of the pulp to external environment occurs, reparative dentinogenesis can be induced by direct pulp capping to maintain pulp tissue vitality and function. These clinical situations require the use of materials that induce dentin repair and, subsequently, formation of a mineralized tissue. Objective: This work aims to assess the effect of tricalcium silicate cements and mineral trioxide aggregate cements, including repairing dentin formation and inflammatory reactions over time after pulp exposure in Wistar rats. Methodology: These two biomaterials were compared with positive control groups (open cavity with pulp tissue exposure) and negative control groups (no intervention). The evaluations were performed in three stages; three, seven and twenty-one days, and consisted of an imaging (nuclear medicine) and histological evaluation (H&E staining, immunohistochemistry and Alizarin Red S). Results: The therapeutic effect of these biomaterials was confirmed. Nuclear medicine evaluation demonstrated that the uptake of 99mTc-Hydroxymethylene diphosphonate (HMDP) showed no significant differences between the different experimental groups and the control, revealing the non-occurrence of differences in the phosphocalcium metabolism. The histological study demonstrated that in mineral trioxide aggregate therapies, the presence of moderate inflammatory infiltration was found after three days, decreasing during follow-ups. The formation of mineralized tissue was only verified at 21 days of follow-up. The tricalcium silicate therapies demonstrated the presence of a slight inflammatory infiltration on the third day, increasing throughout the follow-up. The formation of mineralized tissue was observed in the seventh follow-up day, increasing over time. Conclusions: The mineral trioxide aggregate (WhiteProRoot®MTA) and tricalcium silicate (Biodentine™) present slight and reversible inflammatory signs in the pulp tissue, with the formation of mineralized tissue. However, the exacerbated induction of mineralized tissue formation with the tricalcium silicate biomaterial may lead to the formation of pulp calcifications

Comparative effects of final canal irrigation with chitosan and EDTA

Abstract Chitosan is a natural, biocompatible chelating substance with potential for dental use. This study compared the effects of final canal irrigation with chitosan and EDTA on dentin microhardness, sealer dentin tubules penetration capacity, and push-out strength. Methodology: Fifty canine roots were distributed according to the final irrigation protocol (n=10): G1- 15% EDTA with conventional irrigation; G2- 15% EDTA with Endovac; G3- 0.2% chitosan with conventional irrigation; G4- 0.2% chitosan with Endovac; and G5- without irrigation. Specimens were obturated (AH Plus) and sectioned in 3 slices per root third. The first slice was used for microhardness and sealer penetration assessments under a laser confocal microscope. The second was utilized in a push-out strength test. The third slice was discarded. Data were analyzed using 2-way ANOVA and Tukey's post hoc test (α<0.05). Failure mode was determined at x40 magnification. Results: Microhardness reduction was more significant in groups G2 and G4 (p<0.05). Sealer penetration through dentin was significantly greater in group G2 (p<0.05). There was no significant difference between groups G1, G3, and G4 (p>0.05). In general, all experimental groups presented similar bond resistance (p>0.05) that significantly differed from the control (p<0.001). Mixed type failures were predominant. Conclusions: In general, 0.2% chitosan and 15% EDTA solutions act in a similar manner with regard to the variables studied. The use of Endovac potentiates the effect of these solutions.

In situ effect of a proanthocyanidin mouthrinse on dentin subjected to erosion

Abstract Proanthocyanidin has been shown to be efficient in inhibiting matrix metalloproteinases. Objective The aim of this in situ study was to evaluate the protective effect of Proanthocyanidin-based mouthrinses either with naturally acidic or with a neutral pH applied on dentin subjected to erosion. Methodology Eight volunteers wore one palatal device in two phases (7 days washout) with 16 samples per group (n=8). The groups under study were: First Phase/ G1 - 10% proanthocyanidin mouthrinse (pH 7.0, Experimental group 1 - Purified Grape Seeds Oligomeric Proanthocyanidins), G2 - 10% proanthocyanidin mouthrinse (pH 3.0, Experimental group 2 - Purified Grape Seeds Oligomeric Proanthocyanidins). Second Phase/ G3 - 0.12% chlorhexidine mouthrinse (pH 7.0, Positive control group), G4 - no previous treatment (Negative control group). Each device was subjected to 3 erosive cycles (5 minutes) per day for 5 days. Treatments with different mouthrinses were applied once after the second erosive challenge (5 minutes). Profilometry was used to quantify dentin loss (µm). Results Data were analyzed by repeated measures of ANOVA followed by Fisher's test (p<0.05). G1 (1.17±0.69) and G3 (1.22±0.25) showed significantly lower wear values with no statistical difference between them. G2 (2.99±1.15) and G4 (2.29±1.13) presented higher wear values with no significant differences between them. Conclusion The 10% proanthocyanidin mouthrinse (pH 7.0) could be a good strategy to reduce dentin wear progression.

Adhesive resistance of a copaiba oil-based dentin biomodifier

Abstract This study analyzed the effect of prior application of copaiba oil (CO) emulsions as a dentin cleaning substance on microleakage and microtensile adhesive strength. Twenty-five premolars and sixty-four molars were used for microleakage and microtensile assays. For the microleakage assays, specimens with standard class V cavities were divided (n = 5), according to the tested CO emulsions: CO10%X, CO10%Y, and CO10%Z, as well as chlorhexidine 2% (CHX) and distilled water (DW), as positive and negative controls, respectively. Restorations were performed using the Adper Single Bond® and/or Clearfil SE Bond® systems. Cervical, occlusal, distal and mesial sections were assessed for tracer penetration degree at the composite/tooth interface. For the microtensile assay, healthy molars were divided into sixteen groups, in which artificial caries were induced in half of the groups. Dentin surfaces were treated with CO10%X and CO10%Y, CHX and DW. Microtensile bond strength was measured by fixing each sample to the plate of a universal testing machine operated at a speed of 0.5 mm/minute until failure. Dentin treated with CO10%X showed a lower infiltration rate than dentin treated with the other CO emulsions, CHX2% and DW. According to the microtensile assay, both healthy and affected dentin treated with CO10%X and Adper Single Bond® adhesive system presented higher adhesive strength. CO emulsion, used as a dentin biomodifier, interfered positively in microleakage and improved adhesive strength after acid etching in the Adper Single Bond® adhesive system, or before applying the Clearfil SE Bond® self-etching system.

Influencia de la dentina en el efecto antibacteriano de 2 concentraciones de hipoclorito de sodio en el crecimiento de Enterococcus faecalis ATCC 29212 / Influence of the dentin on the antibacterial effect of 2 concentrations of sodium hypochlorite in the growth of Enterococcus faecalis ATCC 29212

Este estudio in vitro evaluó la influencia de la dentina sobre el efecto antibacteriano contra Enterococcus faecalis ATCC 29212 de dos concentraciones de Hipoclorito de Sodio (NaOCl) 2,5 % y 5 %. Se empleó polvo de dentina a partir de dientes humanos (84 µg/ml) y la supervivencia de la bacteria se evaluó realizando recuento de unidades formadoras de colonias (UFC) a los 10, 30 y 60 segundos. Los datos se analizaron con la prueba estadística ANOVA factorial no encontrándose diferencias estadísticamente significativas entre los grupos con dentina y sin dentina. En conclusión, la dentina en este estudio no influyó en el efecto antibacteriano del Hipoclorito de Sodio en ninguna concentración, ni en los tiempos.

This in vitro study evaluated the influence of dentin on the antibacterial effect against Enterococcus faecalis ATCC 29212 of two concentrations of Sodium Hypochlorite NaOCl 2.5 % and 5 %. Dentin powder was used from human teeth (84 mg/ml) and the survival of the bacteria was evaluated by counting colony forming units (CFU) at 10, 30 and 60 seconds. The data were analyzed with the statistical ANOVA factorial test, finding no statistically significant differences between the groups with and without dentin. In conclusion, the dentin in this study had no inhibitory effect on antibacterial activity of Sodium Hypochlorite and any concentration, nor over time.

Resin-dentin bond stability of etch-and-rinse adhesive systems with different concentrations of MMP inhibitor GM1489

Abstract Enzymatic degradation of the hybrid layer can be accelerated by the activation of dentin metalloproteinases (MMP) during the bonding procedure. MMP inhibitors may be used to contain this process. Objective To evaluate the degree of conversion (DC%), dentin bond strength (µTBS) (immediate and after 1 year of storage in water), and nanoleakage of an experimental (EXP) and a commercial (SB) adhesive system, containing different concentrations of the MMP inhibitor GM1489: 0, 1 µM, 5 µM and 10 µM. Methodology DC% was evaluated by FT-IR spectroscopy. Dentin bond strength was evaluated by µTBS test. Half of beams were submitted to the µTBS test after 24 h and the other half, after storage for 1 year. From each tooth and storage time, 2 beams were reserved for nanoleakage testing. Data were analyzed using ANOVA and Tukey's test to compare means (α=0.05). Results All adhesive systems maintained the µTBS after 1 year of storage. Groups with higher concentrations of inhibitor (5 µM and 10 µM) showed higher µTBS values than groups without inhibitor or with 1 µM. The nanoleakage values of all groups showed no increase after 1 year of storage and values were similar for SB and EXP groups, in both storage periods. The inhibitor did not affect the DC% of the EXP groups, but the SB5 and SB10 groups showed higher DC% values than those of SB0 and SB1. Conclusions The incorporation of GM1489 in the adhesive systems had no detrimental effect on DC%. The concentrations of 5 µM GM1489 for SB and 5 µM or 10 µM for EXP provided higher μTBS than groups without GM1489, in the evaluation after 1 year of storage; whereas the concentration of inhibitor did not affect adhesive systems nanoleakage.

Does Sterilization Affect the Push Out Bond Strength of Experimental Dentin Posts? / ¿Afecta la esterilización la fuerza de adherencia de los postes de dentina experimentales?

ABSTRACT The purpose of this preliminary study is to evaluate the push-out bond strength (PBS) of experimental dentin posts (EDPs) obtained from human and bovine teeth sterilized by autoclaving and gamma radiation. Eighty-four mandibulary premolars were obturated and divided into three post groups: the glass fiber group (Fb) human EDP group (Hm) and the bovine EDP group (Bv). Three subgroups (n=12) were obtained for each EDP groups according to the sterilization methods; no sterilization (Cnt), steam autoclaving (Aut), and gamma radiation (Rad) a total dose of 25 kGy. All posts were cemented to root canals using a dual cured resin cement (Panavia SA). After the micro slices (1mm in thickness) were obtained of each subgroup, PBS test was performed. Data were analyzed using two-way ANOVA and Tukey's multiple comparison tests (α=.05). The post type and sterilization method was significantly effective on the PBS values according to the ANOVA (P<.001). No sterilization apllied EDP groups showed significantly higher PBS values than the sterilized groups (P<.001). Bv_Cnt (9.42 ±1.31) showed significantly lower PBS values than both Fb (12.36 ±1.54) and Hm_Cnt (11.06 ±1.38) groups (P<.001). Both steam autoclaving and gamma radiation affect the PBS values and fracture modes of EDPs negatively. The bovine EDPs are not as effective as human EDPs with regard to the PBS to the root dentin.

RESUMEN El propósito de este estudio preliminar es evaluar el push-out bond strength de los postes de dentina experimentales (PDE) obtenidos de dientes humanos y bovinos esterilizados por autoclave y radiación gamma. Ochenta y cuatro premolares mandibulares fueron obturadores y se dividieron en tres grupos experimentales de postes: el grupo de fibra de vidrio (Fb) grupo PDE humano (Hm) y el grupo PDE bovino (Bv). Se obtuvieron tres subgrupos (n=12) para cada grupo de PDE según los métodos de esterilización; sin esterilización (Cnt), autoclave a vapor (Aut) y radiación gamma (Rad) con una dosis total de 25 kGy. Todos los postes se cementaron a los conductos radiculares utilizando un cemento de resina de curado doble (Panavia SA). Después de que se obtuvieron las micro rebanadas (1 mm de espesor) de cada subgrupo, se realizó una prueba de push-out bond strength. Los datos se analizaron utilizando ANOVA de dos vías y las pruebas de comparación múltiple de Tukey (α=.05). El tipo de poste y el método de esterilización fueron significativamente efectivos en los valores de push-out bond strength según el ANOVA (P <.001). Los grupos de PDE no aplicados a la esterilización mostraron valores de push-out bond strength significativamente mayores que los grupos esterilizados (p <0,001). Bv_Cnt (9.42 ±1.31) mostró valores de push-out bond strength significativamente más bajos que los grupos Fb (12.36 ±1.54) y Hm_Cnt (11.06 ±1.38) (P <.001). Tanto el autoclave al vapor como la radiación gamma afectan negativamente los valores de push-out bond strength y los modos de fractura de los PDE. Los PDE bovinos no son tan efectivos como los PDE humanos con respecto a la fuerza de adhesión a la dentina de la raíz.

Influência de inibidores de metaloproteinases na degradação da camada híbrida / Influence of metalloproteinase inhibitors on hybrid layer degradation

Objetivo: realizar uma revisão de literatura acerca da eficácia de utilização da clorexidina (CHX) e de outros tipos de inibidores de metaloproteinases (MMPs) na resistência de união da camada híbrida. Métodos: a busca bibliográfica foi realizada na base de dados PubMed, nos meses de novembro e dezembro de 2018. A pesquisa ocorreu em três fases, com os descritores previamente selecionados. Foram incluídas publicações dos últimos 10 anos no formato de pesquisas científicas realizadas in vitro ou in vivo. Após análise, obedecendo aos critérios de inclusão e exclusão, foram incluídos sete estudos na presente revisão. Resultados/Revisão de literatura: na interface adesiva, os estudos mostram que as MMPs são ativadas durante a etapa de ataque ácido realizada nos protocolos de aplicação de sistemas adesivos, podendo ser ativada tanto por procedimentos adesivos com condicionamento ácido prévio como por sistemas adesivos autocondicionantes. Além da CHX, outras substâncias foram pesquisadas e se mostraram eficazes na inibição de MMPs. Considerações finais: por meio da inibição da atividade das MMPs, é possível obter uma maior durabilidade da interface adesiva e uma menor degradação hidrolítica do colágeno presente na camada híbrida. (AU)

Objective: to perform a literature review on the efficacy of chlorhexidine (CHX) and other types of metalloproteinase inhibitors (MMPs) on hybrid layer bond strength. Methods: the bibliographic search was performed in PubMed, in the months of november and december of 2018. The research was carried out in three phases with the previously selected descriptors. Publications have been included in the last 10 years in the form of scientific research conducted in vitro or in vivo. After analysis, following the inclusion and exclusion criteria, 7 studies were included in the present review. Results / Literature review: in the adhesive interface, the studies show that the MMPs are activated during the acid attack stage carried out in the application protocols of adhesive systems, and can be activated either by adhesive procedures with prior acid conditioning or self-etching adhesive systems. In addition to CHX, other substances were investigated and shown to be effective in inhibiting MMPs. Final considerations: through the inhibition of the MMPs activity it is possible to obtain a greater durability of the adhesive interface and lower hydrolytic degradation of the collagen present in the hybrid layer. (AU)