Bond strength of bulk-fill resin composites: the effect of cavity preparation and aging

Aim: Evaluating the resin-dentin bond strength of Class II conventional and bulk-fill composite restorations, using different cavity sizes before and after aging. Methods: Seventy-five human molars were distributed into groups according to the buccolingual width of the cavities, conservative (n=25) and extended (n=50). They were divided according to the restorative material: conventional (Z100/control group) or bulk-fill resin composites (Filtek Bulk Fill/FBF; Tetric N Ceram Bulk Fill/TNCBF; Filtek Bulk Fill Flow/FBFF; Surefill SDR flow/SDR). The restored teeth were sectioned on sticks (n=50 per restorative materials + width cavities group), half were stored in Water/Ethanol 75% for 30 days and the other half were submitted to the immediate microtensile bond strength (µTBS) test. Data were analyzed applying the Three-Way Analysis of Variance (ANOVA), Bonferroni test, test t, and Weibull analyses (p<0.05). Results: SDR and FBF presented lower µTBSvalues for extended preparation when compared to the conservative preparation, before aging. After aging, only for the FBFF, a decrease in the µTBSvalues was observed. Comparing the µTBSvalues, before and after aging, the SDR demonstrated lower µTBSvalues after aging when the conservative cavity was used. A decrease in the µTBSvalues was observed for the Z100, the FBF and, the FBFF, after aging, when the extended cavity was used. Conclusion: The effect of cavity preparation and aging on the resin-dentin of Class II is material dependent. Most of the bulk-fill resin composites evaluated presented a similar performance to the conventional resin composites for all the conditions of this study

Biomechanical, operative and biological aspects of the cervical margin relocation: a case report / Aspectos biomecânicos, operatórios e biológicos da recolocação da margem cervical com resina composta em cavidades classe II com margens profundas: um relato de caso

The clinical success of tooth-colored indirect restorations has been confirmed in several studies. However, inlays and onlays restorations in Class II cavities with deep gingival margins can still be considered a clinical challenge. With the purpose of facilitating the execution of the operative procedures in intrasulcular margins and reducing the risk of restorative failures, the technique of cervical margin relocation has been explored as a noninvasive alternative to surgical crown lengthening. This work aims at discussing through a case report the biomechanical, operative and biological aspects in the treatment of teeth with deep gingival margins. Therefore, given the therapy applied in the clinical case presented, it is concluded that the cervical margin relocation with composite resin is advantageous since it eliminates the need for surgery, allowing the implementation of indirect restorations in fewer clinical sessions, not causing damage to periodontal tissues once it provided good finishing and polishing with the establishment of a correct emergence profile, allowing flawless maintenance of gingival health after one year. (AU)

Sucesso clínico das restaurações indiretas livres de metal tem sido confirmado em diversos estudos. No entanto, restaurações parciais indiretas em cavidades do tipo classe II com margens profundas ainda podem ser consideradas um desafio clínico. Com a proposta de facilitar a execução dos procedimentos operatórios em margens intra-sulculares e reduzir a ocorrência de falhas, a técnica de elevação da margem gengival em resina composta tem sido explorada como alternativa não invasiva à cirurgia de aumento de coroa clínica. Este trabalho tem a intenção de discutir através de um relato de caso clínico os aspectos biomecânicos, operatórios e biológicos no tratamento de dentes com margens cervicais profundas. Sendo assim, conclui-se que a técnica de elevação da margem gengival com resina composta é vantajosa, pois elimina a necessidade de cirurgia permitindo a execução de restaurações indiretas em menos sessões clínicas, não gerando danos aos tecidos periodontais, desde que haja um bom acabamento e polimento, com estabelecimento de um correto perfil de emergência. (AU)

Enfoque de Tratamiento de una Adolescente con Amelogénesis Imperfecta / Treatment Approach for an Adolescent with Amelogenesis Imperfecta

La amelogénesis imperfecta (AI) es un grupo de tras-tornos hereditarios, clínica y etiológicamente hete-rogéneos, derivados de mutaciones genéticas, que se caracterizan por anomalías cualitativas y cuanti-tativas del desarrollo del esmalte, pudiendo afectar la dentición primaria y/o permanente. El tratamiento del paciente con AI es complejo y multidiscliplinario; supone un desafío para el odontólogo, ya que por lo general están involucradas todas las piezas dentarias y afecta no solo la salud buco dental sino el aspecto emocional y psicológico de los pacientes. Con el obje-tivo de describir el tratamiento integral y rehabilita-dor realizado en una paciente con diagnóstico de AI tipo III, se reporta el caso de un adolescente de sexo femenino de 13 años, que concurrió en demanda de atención a la Cátedra de Odontología Integral Niños de la Facultad de Odontología de la Universidad de Buenos Aires (FOUBA), cuyo motivo de consulta fue la apariencia estética y la hipersensibilidad de sus pie-zas dentarias. Durante el examen clínico intraoral, se observó que todas las piezas dentarias presentaban un esmalte rugoso, blando, con irregularidades y una coloración amarronada, compatible con diagnóstico de Amelogénesis Imperfecta tipo III hipomineralizada. Conclusión: El tratamiento rehabilitador de la AI en los pacientes en crecimiento y desarrollo estará diri-gido a intervenir de manera integral y temprana para resolver la apariencia estética y funcional, evitar las repercusiones sociales y emocionales, y acompañar a los pacientes y sus familias (AU)

Amelogenesis imperfecta (AI) is a group of clinically and etiologically heterogeneous hereditary disorders, derived from genetic mutations, characterized by qualitative and quantitative anomalies of enamel development, which can affect primary and/or permanent dentition. The treatment of patients with AI is complex and multidisciplinary, it is a challenge for the dentist, since in general all the teeth are involved and it affects not only oral health but also the emotional and psychological aspect of the patients. Objective: To describe the comprehensive and rehabilitative treatment carried out in an adolescent patient with a diagnosis of type III AI. Case report: The case of a 13-year-old female patient, who required dental attention at the Department of Dentistry for Children of the School of Dentistry of the University of Buenos Aires, whose reason for consultation was esthetic appearance and hypersensitivity of her teeth. In the intraoral clinical examination, it was observed that all the teeth had rough, soft enamel, with irregularities and a brownish color, compatible with the diagnosis of type III hypomineralized Amelogenesis Imperfecta. Conclusion: Rehabilitative treatment of AI in growing and developing patients will be aimed at early and comprehensive intervention to resolve esthetic and functional appearance, avoid social and emotional repercussions and accompany patients and their families (AU)

Restorative treatment decisions regarding approximal and occlusal carious lesions among general dental practitioners in Palestine

Aim: To investigate restorative decisions made by dentists and to examine what demographic characteristics are associated with the decisions for managing approximal and occlusal lesions. Methods: A questionnaire was randomly sent to 900 Palestinian dentists. It noted the demographic details of the dentists and the years of experience. The questionnaire evaluated the respondents for their treatment decisions regarding approximal and occlusal carious lesions. The data was analyzed using the IBM SPSS statistics for windows. The associations between gender and years of experience of the respondents and their restorative decisions were assessed. Results: The response rate was 58.2%. For occlusal carious lesions, 93.9% of the respondents would postpone operative treatment until the lesion was in dentine (grade 3 to 5). For approximal lesions, intervention was deemed appropriate by 92.6% of the respondents when there was radiographic evidence of a carious lesion reaching the DEJ or deeper. Around 53% preferred to prepare approximal lesions according to the traditional principles of cavity preparation. For both approximal and occlusal lesions, the participants opted for resin composites. Statistically, there was a significant association between the restorative decisions with the years since graduation and gender. Conclusion: The study showed variations between the treatment decisions of Palestinian dentists. The subjects chose conservative treatment plans but still adhered to traditional learned practices especially when cavity preparation for approximal lesions was concerned. The years since graduation and gender played a significant role in the choice of treatment opted for. Resin composites seemed to be a popular choice for treatment

Remoção seletiva de tecido cariado e proteção pulpar indireta: relato de casos clínicos / Selective caries removal and indirect pulp capping: clinical cases report

Objetivo: este artigo se propõe a discutir o tratamento de lesões profundas de cárie em molares permanentes, através da técnica de remoção seletiva de tecido cariado e restauração de resina composta, em dois casos clínicos, utilizando apenas sistema adesivo (caso 1) ou proteção pulpar indireta com cimento de hidróxido de cálcio (caso 2). Relato de casos: os indivíduos foram diagnosticados com dentes apresentando lesões profundas de cárie, isto é, com mais de 50% em profundidade da dentina, confirmada pelo exame radiográfico interproximal. O conjunto de resultados de testes de sensibilidade pulpar positivo ao frio e teste de percussão horizontal e vertical negativos, juntamente com a ausência de dor espontânea e normalidade do periápice (radiografia periapical), completaram os requisitos exigidos para execução da técnica de remoção seletiva de dentina cariada amolecida. Os dentes receberam restaurações adesivas na mesma sessão, sobre a dentina cariada amolecida da parede pulpar que havia recebido forramento de cimento de hidróxido de cálcio ou não, dependentes de uma randomização. Ambos os casos apresentados mostraram sucesso clínico em acompanhamento de 18 meses, tanto na manutenção da vitalidade pulpar quanto na sobrevivência da restauração. Considerações finais: com base nos casos apresentados, sabendo das limitações deste modelo de estudo, e em concordância com a literatura, a remoção seletiva de tecido cariado pode ser executada com sucesso no tratamento de lesões profundas de cárie, respeitando-se todos os passos da técnica, e parece não haver necessidade de uso de proteção pulpar indireta.(AU)

Objective: this article aims to discuss the treatment of deep caries lesions in permanent molars through the selective caries tissue removal technique and composite resin restoration of two clinical cases, using only an adhesive system (case 1) or an indirect pulp protection of calcium hydroxide cement (case 2). Cases report: the participants were diagnosed with deep caries lesions, that is, more than 50% in depth of the dentin involved, which was confirmed by the interproximal radiography. In both cases, it was obtained positive response to cold test, negative response to horizontal and vertical percussion tests, absence of spontaneous pain and no periapical lesion (periapical radiography), which completed the requirements for performing the selective caries removal of soft dentin. These teeth received adhesive restorations in the same session, under the softened carious dentin of the pulp wall that had received calcium hydroxide cement or not, depending on randomization. Both cases had clinical success in the 18-month follow- -up, showing pulp vitality and restoration survival. Final considerations: based on the clinical cases reported, considering de limitations of this study model, and in agreement with the literature, the selective removal of carious tissue can be successfully performed in the treatment of deep carious lesions, respecting all the steps of the technique and indirect pulp protection seems to be unnecessary.(AU)

Filtración marginal y contracción en la polimerización en nuevas resinas Bulk Fill: una revisión de la literatura / Marginal leakage and polymerization shrinkage in new Bulk Fill resins: a review of the literature

A pesar de los avances e innovaciones de los materiales dentales, la microfiltración marginal y la contracción durante la polimerización continúan siendo una de las causas principales del fracaso de los tratamientos en odontología restauradora. Un sellado marginal correcto será posible cuando las fuerzas de adhesión superen las fuerzas generadas por la contracción de polimerización y las fuerzas generadas por los cambios dimensionales térmicos posteriores a la polimerización, por lo que investigaciones previas demostraron que estas limitaciones pueden ser superadas con el uso de resinas Bulk Fill como material de relleno de cavidades extensas y profundas de dientes posteriores. Estas resinas. de relleno masivo, están recibiendo atención, principalmente porque se pueden colocar, a diferencia de las resinas convencionales, en incrementos de 4 mm sin afectar la contracción de la polimerización, la adaptación de la cavidad o el grado de conversión. El objetivo de la presente revisión bibliográfica es describir la contracción de polimerización y la consecuente filtración marginal que sufren las resinas compuestas para el sector posterior Bulk Fill con base de datos de la literatura (AU)

Despite advances and innovations in dental materials, marginal microfiltration and shrinkage during polymerization continue to be one of the main causes of treatment failure in Restorative Dentistry. A correct marginal seal will be possible when the adhesion forces exceed the forces generated by polymerization contraction and the forces generated by post-polymerization thermal dimensional changes, for which previous research has shown that these limitations can be overcome with the use of Bulk Fill resins as filling material for large and deep posterior tooth cavities, these massive filling resins are receiving attention mainly because they can be placed, unlike conventional resins, in 4 mm increments without affecting polymerization shrinkage. , cavity adaptation or degree of conversion. The objective of the present bibliographic review is to describe the polymerization contraction and consequent marginal filtration suffered by Composite Resins for the Bulk Fill posterior sector with a literature database (AU)

Mechanical and thermal stress analysis of hybrid ceramic and lithium disilicate based ceramic CAD-CAM inlays using 3-D finite element analysis / Análise do estresse mecânico e térmico de inlays de cerâmica hibrida e de cerâmica a base de dissilicato de lítio através da análise em 3D de elementos finitos

Objective: The aim of this study was to analyze mechanical and thermal stresses of hybrid ceramic and lithium disilicate based ceramic of CAD/CAM inlays using 3D Finite element analysis. Material and Methods:A three dimensions finite element model of permanent maxillary premolar designed according to standard anatomy with class II cavity preparation for inlay restored with two different ceramic materials: 1- Hybrid ceramic (Vita Enamic), 2- Lithium disilicate based ceramic (IPS e.max CAD). Totally six runs were performed on the model as: One loading case for each restorative material was tested in stress analysis; seven points of loading with 140N vertically applied at palatal cusp tip and cusp slop, marginal ridges and central fossa while the models base was fixed as a boundary condition in the two cases. Two thermal analysis cases were performed for each restoration material by applying 5ºC and 55ºC on the crown surface including the restoration surface. Results:The results of all structures were separated from the rest of the model to analyze the magnitude of stress in each component. For each group, maximum stresses on restorative materials, cement, enamel, and dentin were evaluated separately. Both ceramic materials generated similar stress distribution patterns for all groups when a total occlusal load of 140 N was applied. Conclusion: Thermal fluctuations of temperature have a great influence on the stresses induced on both restoration and tooth structure. IPS e.max CAD produced more favorable stresses on the tooth structure than Vita Enamic. (AU)

Objetivo: O objetivo deste estudo foi analisar o estresse mecânico e térmico de inlays de cerâmica hibrida e a base de dissilicato de lítio através da análise em 3D de elementos finitos. Material e Métodos: Foi realizado o design de um modelo de três dimensões em elementos finitos de um pré-molar superior de acordo com os padrões anatômicos de um preparo de cavidade classe II para restauração de inlay em dois tipos de cerâmicas diferentes: 1 Cerâmica hibrida (Vita Enamic), 2 ­ Cerâmica a base de dissilicato de lítio (IPS e.max CAD). No total, seis execuções foram realizadas no modelo como: Uma carga para cada material restaurador foi testado para análise de tensão; sete pontos de carga com 140N foi aplicado verticalmente na ponta da cúspide palatina, saliência da cúspide, cristas marginais e fossa central enquanto a base do modelo foi fixada como uma condição de limite nos dois casos. Duas análises térmicas foram realizadas para cada material de restauração, aplicando 5ºC e 55ºC na superfície da coroa, incluindo a superfície da restauração. Resultados: Os resultados de todas as estruturas foram separados do resto do modelo para analisar a magnitude do estresse de cada componente. Para cada grupo, o máximo de estresse nos materiais restauradores, cemento, esmalte e dentina foram avaliados separadamente. Padrões similares de distribuição de estresse foram gerados em todos os grupos para ambos os materiais cerâmicos, quando a carga oclusal de 140 N foi aplicada. Conclusão: As variações térmicas de temperatura têm uma grande influência nas tensões induzidas na restauração e na estrutura dentária. IPS e.max CAD produziu tensões mais favoráveis na estrutura dentária do que o Vita Enamic (AU)

Rehabilitación oral adhesiva: diagnóstico y tratamiento. Caso clínico / Adhesive oral rehabilitation: diagnosis and treatment. A clinical case

El objetivo de este reporte de caso clínico es presentar una rehabilitación integral adhesiva resuelta por alumnos de grado de la Facultad de Odontología de la Universidad de Buenos Aires (FOUBA), bajo un protocolo de abordaje terapéutico que simplifica su realización. Esta sistematización hace foco en un abordaje completamente aditivo con la finalidad de devolver la salud, la función y la estética de manera predecible. Un paciente de 55 años concurrió a la consulta por motivos estéticos. En el diagnóstico se evidenciaron desgastes severos producto de la parafunción. Se realizó una rehabilitación oral adhesiva seleccionando a la cerámica vítrea como material restaurador. El diagnóstico y la comprensión de su etiología son fundamentales para realizar un tratamiento conservador con restauraciones adheridas y con alto grado de predictibilidad, que se prolongará en el tiempo, gracias a la utilización de una placa orgánica y a los controles de mantenimiento correspondientes (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)

Self-reported habits regarding dental bur use and conditioning among academic and non-academic argentinian dentists / Autoreporte sobre hábitos de uso y acondicionamiento de fresas de odontólogos argentinos en ámbitos académicos y no académicos

ABSTRACT The removal of tissues affected by caries lesions is one of the mostfrequentprocedures in daily dental practice. The aim ofthis study was to collect information about the habits of members of the academic and non-academic dental community in Argentina regarding the use and conditioning of burs employed in the removal of dentin during the treatment of carious lesions. A 14-item questionnaire was prepared, and once validated in small groups, it was sent to three lists of dental subscribers through the computer services area of the School of Dentistry, University of Buenos Aires, Argentina (FOUBA). By the deadline for receiving responses, which was set as four weeks after the sending date, 294 replies were received. Results: percentage (95%CI): 47.93% (42.18-53.68%) of the respondents were faculty members, of whom 37.24% (31.68-42.81%) claimed to belong to FOUBA. Of the respondents, 26.90% (21.79-32.00%) reported being under 35 years old, 37.59% (32.01-43.16%) 36 to 45 years old, 22.07% (17.30-26.84%) 46 to 55 years and 11.38% (7.72-15.03%) over 55 years. Regarding bur type, 68.07% (62.31%-73.44%) claimed to use round burs to remove carious dentin and 27.72% (22.60%-23.31%) round + others. Regarding rotary speed, 22.07% (17.30-26.84%) use medium speed, 32.76% (27.36-38.16%) use high speed, and 32.76% (27.36-38.16%) use medium + super high. Only 17.93% (13.5222.35%) indicated that they know how to quantify the number of times they use their burs, while 50.34% (44.59-56.10%) of the respondents said that they use burs "until they no longer cut", 23.79% (18.89-28.69%) use them 1 to 5 times. 98.27% (96.77-99.77%) said they clean their burs once used. When the answers regarding the use of rubber dam were compared with area of specialization (Chi-square), it was found that faculty members mention the use of burs under rubber dam always or almost always 74.82% (67.60-82.04%) while outside the academic field, 51.01% (42.98-59.03%) of dentists say that they never or almost never do so (p <0.001). Conclusion: Most respondents state that they sterilize their rotary instruments in some way after use. About half of them do not keep track of the number of uses and use burs "until they no longer cut".

RESUMEN La eliminación de los tejidos afectados por las lesiones de caries es uno de los procedimientos más realizados en la práctica diaria de la odontología. El objetivo de este estudio fue recolectar información acerca de los hábitos de miembros de la comunidad odontológica de la Argentina en cuanto a la selección, utilización y acondicionamiento de fresas para la remoción de dentina en el tratamiento de lesiones cariosas. Se elaboró un cuestionario de 14 reactivos que fue validado en pequeños grupos. Una vez definido el formato final se lo envió a tres listas de suscriptores odontólogos a través del de área de Informática de la Facultad de Odontología de la Universidad de Buenos Aires (FOUBA). El plazo para la recepción de respuestas se estableció en cuatro semanas luego del cual se obtuvieron 294 réplicas. Resultados: porcentaje (IC95%), el 47,93% (42,18-53,68%) eran docentes, de los cuales el 37,24% (31,68-42,81%) afirmó ser docente de la UBA. El 26,90% (21,79-32,00%) refirió tener menos de 35 años, el 37,59% (32,01-43,16%) entre 36y 45 años, el 22,07% (17,30-26,84%) entre 46 y 55 años y el 11,38% (7,72-15,03%) más de 55 años. El 68,07% (62,31%-73,44%) afirmó utilizar fresas redondas y el 27,72% (22,60%-23,31%) redondas + otras. En cuanto a la velocidad utilizada: media velocidad: 22,07% (17,30-26,84%), superalta: 32,76% (27,3638,16%), media + superalta: 32,76% (27,36-38,16%). Sólo el 17,93% (13,52-22,35%) indicó que sabe cuantificar la cantidad de usos que les dan a sus fresas, en tanto que el 50,34% (44,5956,10%) de los consultados afirmó que utiliza las fresas "hasta que no corten más", el 23,79% (18,89-28,69%) le da entre 1 y 5 usos. El 98,27% (96,77-99,77%) afirmó que limpia sus fresas una vez utilizadas. Cuando se contrastaron las respuestas respecto al uso de aislamiento con el área de desempeño (Chi-cuadrado) se encontró que los docentes refieren utilizar las fresas con aislamiento absoluto siempre o casi siempre 74,82% (67,60-82,04%) mientras que fuera del ámbito académico el 51,01% (42,98-59,03%) respondieron que nunca ó casi nunca lo hacen (p < 0,001). Conclusión: la mayoría afirma que acondiciona de alguna manera el instrumental rotatorio luego de su uso, alrededor de la mitad no lleva registro del número de usos y sostiene que utiliza las fresas "hasta que no cortan más".

Assessment of Marginal Adaptation Before and After Thermo-Mechanical Loading and Volumetric Shrinkage: Bulk Fill versus Conventional Composite / Evaluación de la Adaptación Marginal Antes y Después de la Carga Termomecánica y la Contracción Volumétrica: Relleno Bulk-Fill- versus Compuesto Convencional

ABSTRACT: The objective of the study was to evaluate marginal adaptation of Class II mesial-occlusal-distal (MOD) restorations before and after thermo-mechanical loading and volumetric shrinkage of the bulk-fill vs conventional composite resin. For marginal adaptation assessment, 24 Class II MOD cavities with cervical margins extending 1.0 mm below (distal) and 1.0 mm beyond (mesial) the cement-enamel junction were prepared in extracted human molars. The teeth were filled as follows: Group A - bulk-fill with SureFil SDR flow (first increment, 4 mm; second increment, 2 mm); Group B - bulk-fill with SureFil SDR flow as a base (first increment, 4 mm) and covered with the conventional nanohybrid composite Esthet-X HD (second increment, 2 mm); and Group C - incrementally filled with Esthet-X HD. Marginal adaptation was evaluated by scanning electron microscopy before and after thermomechanical loading (240,000 loading cycles and simultaneous 600 thermal cycles). To evaluate volumetric polymerization shrinkage, a semi-spherical mold was filled with the tested composites and placed in an AccuVol device after light curing. Both before and after loading, marginal adaptation in cervical dentin was superior (p < 0.05) for Groups A and B compared with Group C. In cervical enamel, Group B showed better marginal adaptation than Group C, and Group A presented intermediary results, between Groups B and C. Furthermore, bulk-fill flow resulted in greater shrinkage than Esthet-X HD. A significant improvement of marginal adaptation was observed when bulkfill flow was used instead of conventional composite resin both before and after thermomechanical loading. However, the bulk-fill flow presented higher volumetric polymerization shrinkage than the conventional composite.

RESUMEN: El objetivo de este trabajo consistió en evaluar la adaptación marginal de las restauraciones mesiales-oclusales-distales (MOD) de Clase II antes y después de la carga termo-mecánica y la contracción volumétrica de la carga compuesta de resina "bulk-fill" en comparación con resina convencional. Para la evaluación de adaptación, se prepararon 24 cavidades MOD de Clase II en molares humanos extraídos, los que se restauraron de la siguiente manera: Grupo A: restaurado con resina fluida Bulk-Fill SureFilSDR (primer incremento, 4 mm; segundo incremento, 2 mm); Grupo B: restaurado con resina fluida Bulk-Fill SureFil SDR (primer incremento, 4 mm) y cubierto con resina compuesta nanohíbrida Esthet-X HD (segundo incremento, 2 mm); y Grupo C - rellenado incrementalmente con Esthet-X HD. La adaptación marginal se evaluó mediante microscopía electrónica de barrido antes y después de la carga termomecánica (240.000 ciclos de carga y 600 ciclos térmicos simultáneos). Para evaluar la contracción volumétrica de la polimerización, se llenó un molde semiesférico con los compuestos probados y se colocó en un dispositivo AccuVol después del fotopolimerización. Tanto antes como después de la carga, la adaptación marginal en la dentina cervical fue superior (p <0,05) para los grupos A y B en comparación con el grupo C. En el esmalte cervical, el grupo B mostró una mejor adaptación marginal que el grupo C, y el grupo A presentó resultados intermedios, entre Grupos B y C. Se observó una mejora significativa de la adaptación marginal al utilizar la resina fluida Bulk-Fill en lugar de resina compuesta convencional tanto antes como después de la carga termomecánica. Sin embargo, la resina fluida 'Bulk-Fill' presentó una mayor contracción volumétrica de polimerización que el compuesto convencional.

Microfiltración de preparación cavitaria clase II restaurado con tres compuestos dentales diferentes materiales de restauración (Estudio comparativo in vitro) / Microleakage of class II cavity preparation restored with three different dental composite restorative materials (A Comparative in Vitro Study)

This in-vitro study aimed to evaluate marginal microleakage of CL II cavity preparation restored with three types of resin based dental composite. Forty five sound maxillary first premolar teeth were selected and standardized Class II box only cavities were prepared in the mesial surface of each tooth. The teeth then were restored with micro-filled resin hybrid universal composite (G-ænial POSTERIOR, GC japan). Nano-hybrid universal composite (Filtek™ Z350 XT, 3m ESPE germany). Nanofiber reinforced nano-hybrid universal composite (NovaProTM Fill, nanova usa). After finishing, the teeth were subjected to 500 thermal cycles at 5º-55ºC and mechanical load cycling (50,000 load cycle of 50 N). Teeth were kept in 2% methylene blue for 3 days and then blocked in clear acrylic before sectioning with microtome. Microleakage was evaluated by stereomicroscope (20 X). Data were analyzed statistically by Kruskal-Wallis test. The least microleakage occurred around the group C (NovaProTM Fill) and the maximum microleakage was seen in group B (Filtek™ Z350 XT) but there was no statistically significant difference between the groups.

Influence of cavo superficial enamel acid-etching on the microtensile bond strength of low-shrinkage composite resin / Influência do condicionamento ácido do ângulo cavo superficial na resistência adesiva de restaurações em um compósito de baixa contração de polimerização

Introduction: To prevent the shrinkage stresses produced during polymerization, composite resins of low polymerization shrinkage were developed. Objective: To evaluate the microtensile bond strength in class I cavities restored by acid-etching the cavosurface angle and with composite resins indicated for posterior teeth. Material and method: 48 healthy molars were selected and divided into six groups (n = 8), considering that the cavosurface enamel of three groups was etched with 35% phosphoric acid. The teeth were restored with the Clearfil SE Bond adhesive system and Filtek Z350 XT, Empress Direct, and Charisma Diamond composite resins, which were light-cured for 40 seconds. After 24 hours, the teeth were taken to a cutting machine, which produced sections in the buccolingual and mesiodistal directions. This resulted in toothpicks of 0.9×0.9 mm that were taken to the universal testing machine for the microtensile bond strength test. Statistical analysis was performed with ANOVA and Tukey's test (p < 0.05). Result: There was no statistically significant difference between the groups evaluated. Conclusion: Acid-etching the cavosurface angle did not affect the performance of restorations, probably due to the adhesive system used.

Introdução: Com o intuito de se evitar as tensões geradas durante a contração de polimerização das resinas compostas, foram desenvolvidas as resinas compostas de baixa contração de polimerização. Objetivo: Avaliar a resistência à microtração em cavidades classe I restauradas com tratamento ácido do ângulo cavo superficial e resina composta indicada para dentes posteriores. Material e método: Foram selecionados 48 molares hígidos que foram divididos em 6 grupos (n=8), sendo que 3 desses tiveram o esmalte cavo superficial condicionado com ácido fosfórico a 35%. Os dentes foram restaurados com o sistema adesivo Clearfil SE Bond e as resinas compostas Filtek Z350 XT, Empress Direct e Charisma Diamond, fotoativadas por 40 segundos. Após 24 horas, os dentes foram levados para máquina de corte, na qual foram realizados cortes no sentido vestíbulo-lingual e no sentido mésio-distal obtendo - se palitos de 0,9×0,9 mm que foram levadas para a máquina de ensaio universal para a realização do teste de microtração. Para análise estatística foi realizado análise de variância e teste de Tuckey (p < 0,05). Resultado: Não houve diferença estatística significante entre os grupos avaliados. Conclusão: O condicionamento ácido do ângulo cavo superficial não influenciou no desempenho das restaurações provavelmente devido ao sistema adesivo utilizado.

The use of a liner under different bulk-fill resin composites: 3D GAP formation analysis by x-ray microcomputed tomography

Abstract Gap formation of composite resin restorations is a serious shortcoming in clinical practice. Polymerization shrinkage stress exceeds the tooth-restoration bond strength, and it causes bacterial infiltration within gaps between cavity walls and the restorative material. Thus, an intermediate liner application with a low elastic modulus has been advised to minimize polymerization shrinkage as well as gap formation. Objective: The purpose of this in vitro study was to assess gap formation volume in premolars restored with different bulk-fill composites, with and without a resin-modified glass-ionomer cement (RMGIC) liner, using x-ray micro-computed tomography (micro-CT). Methodology: Sixty extracted human maxillary premolars were divided into six groups according to bucco-palatal dimensions (n=10). Standardized Class II mesio-occluso-distal cavities were prepared. G-Premio Bond (GC Corp., Japan) was applied in the selective-etch mode. Teeth were restored with high-viscosity (Filtek Bulk Fill, 3M ESPE, USA)-FB, sonic-activated (SonicFill 2, Kerr, USA)-SF and low viscosity (Estelite Bulk Fill Flow, Tokuyama, Japan)-EB bulk-fill composites, with and without a liner (Ionoseal, Voco GmbH, Germany)-L. The specimens were subjected to 10,000 thermocycles (5-55°C) and 50,000 simulated chewing cycles (100 N). Gap formation based on the volume of black spaces at the tooth-restoration interface was quantified in mm3 using micro-computed tomography (SkyScan, Belgium), and analyses were performed. Data were analyzed using repeated-measures ANOVA and the Bonferroni correction test (p < 0.05). Results: The gap volume of all tested bulk-fill composites demonstrated that Group SF (1.581±0.773) had significantly higher values than Group EB (0.717±0.679). Regarding the use of a liner, a significant reduction in gap formation volume was observed only in Group SFL (0.927±0.630) compared with Group SF (1.581±0.773). Conclusion: It can be concluded that different types of bulk-fill composite resins affected gap formation volume. Low-viscosity bulk-fill composites exhibited better adaptation to cavity walls and less gap formation than did sonic-activated bulk-fill composites. The use of an RMGIC liner produced a significant reduction in gap formation volume for sonic-activated bulk-fill composites.

Effect of flowable composite or glass ionomer liners on shrinkage stress of a composite resin / Efecto de recubrimientos con resinas de baja viscosidad o ionómero vitreo sobre la tensión por contracción de una resina compuesta

ABSTRACT The aim of this study was to evaluate the effect of flowable composite or glass ionomer liners on the shrinkage stress of a restorative composite resin. Fifteen previously sandblasted metal boxes were attached to a universal mechanical testing machine (INSTRON 1011, Instron Corporation). Five of these boxes were filled with Filtek Z350 XT (FXT) Universal Restorative A2 (3M ESPE) (Group 1 or Control). Two further groups of 5 boxes were prepared by interposing a layer of Vitrebond Light Cure Glass Ionomer 3M ESPE (VGI) (Group 2 or G.I.) or Filtek Z350 XT Flowable Restorative A2 3M ESPE (FFR) (Group 3 or Flowable) between the box and the composite resin, completing with the same volume of composite as in Group 1. Upon activating lightcuring, the filled boxes mounted on the testing machine were videoed for 60 seconds (40 s photoactivation and 20 s postcuring), timed with a digital chronometer. Force values were recorded in newtons and converted into stress according to contact surface. Stress values were recorded every 10 s. Results were analyzed using repeated measures ANOVA. Mean and standard deviation in kPa (stress) recorded for each group were: Control group: 126.2 (30.8); G.I.: 48.4 (18); Flowable: 27.9 (19.5). Statistical analysis showed significant differences between the control group and the rest (p<0.01), with no significant difference between groups with glass ionomer liners and flowable resin liners (G.I. and Flowable). Under the experimental conditions of this study, it can be concluded that polymerization shrinkage stress can be reduced by the presence of a liner between the preparation and the restorative material.

RESUMEN El objetivo de este trabajo fue evaluar el efecto de la colocación de una capa de Composite flow o Ionómero vítreo sobre la tensión de contracción de un composite para restauración. Se utilizaron 15 cajas metálicas previamente arenadas y conectadas a la máquina universal para ensayos mecánicos (INSTRON 1011, Instron Corporation). Cinco de estas cajas (G1) se rellenaron con Filtek Z350 XT (FXT) Universal Restorative A2 3M ESPE. Al iniciar la activación de la unidad de curado se comenzaba a registrar con una cámara de video y un cronómetro digital desde el comienzo de la activación de la lámpara hasta 60 s después, registrando los valores post curado durante 20 s. Los valores de fuerza generados por la polimerización fueron registrados en newton de cada 10 s para los 15 ensayos. Los valores fueron convertidos en tensión de contracción según la superficie de contacto. Se realizaron además dos grupos de cajas (5 en cada una) en los cuales se colocaron una capa inicial de Vitrebond Light Cure Glass Ionomer 3M ESPE (VGI) (G2 o IV) y Filtek Z350 XT Flowable Restorative A2 3M ESPE (FFR) (G3 o Flow) y se completó con el mismo volumen de composite de las del GI. Los resultados obtenidos fueron analizados por medio de ANOVA para mediciones repetidas. La media y la desviación estándar en kPa (tensión o estrés de contracción) registrado para cada grupo fueron: Grupo control: 126.2 (30.8); IV: 48.4(18); Flow: 27.9(19.5). El análisis estadístico mostró diferencias estadística mente significativas entre el grupo control y el resto (p=0.00), pero no hubo diferencias significativas entre la presencia de Ionómero vítreo o Composite Flow (IV y Flow). En las condiciones experimentales de este trabajo puede concluirse que la tensión de contracción generada durante la polimerización puede ser disminuida por la presencia de algún material interpuesto entre la preparación y el composite restaurador.

Effects of papain-based gel used for caries removal on macrophages and dental pulp cells

Abstract Papain-based gel is used for chemical-mechanical caries removal and present antimicrobial and anti-inflammatory activities. However, its effects on dental pulp cells and on macrophages remains largely unknown. Therefore, the aim of this study was to investigate whether the papain-based gel Papacárie Duo® acts as an immunomodulator in lipopolysaccharide (LPS)-activated macrophages and its effects on dental pulp cells . J774.1 macrophage and OD-21 dental pulp cells were stimulated with 0.5% and 5% of Papacárie Duo®, following pre-treatment or not with LPS. After 24 h, a lactate dehydrogenase assay was used to measure cytotoxicity, a tetrazolium-based colorimetric assay (MTT) was used to measure cell viability, and qRT-PCR was used to analyze relative gene expression of Ptgs2, Il10, Tnf, Mmp9, Runx2, Ibsp and Spp1. Papacárie Duo® was cytotoxic and reduced cell viability at 5% but not at 0.5% in both cultures. In macrophages, Papacárie Duo® increased the expression Il10 and LPS-induced Ptgs2, but it did not affect Tnf or Mmp9. In OD-21 cells, Papacárie Duo® inhibited Runx2 and Ibsp expression, but stimulated Spp1 expression. Papain-based gel presented a concentration dependent cytotoxicity, without affecting cell viability, for dental pulp cells and macrophages. Interestingly, the gel presented an inhibitory effect on pulp cell differentiation but modulated the activation of macrophages stimulated with LPS. We speculate that in dental pulp tissue, Papacárie Duo® would impair reparative dentinogenesis but could activate macrophages to perform their role in defense and inflammation.

Resumo O gel à base de papaína é utilizando para remoção químico-mecânica do tecido cariado e apresenta propriedades antimicrobianas e anti-inflamatórias Entretanto, seu efeito sobre as células da polpa dentárias e macrófagos é desconhecido. Portanto, o objetivo deste estudo foi investigar o efeito de um gel de papaína (Papacárie Duo®) em células indiferenciadas da polpa dentária e a capacidade de induzir a ativação e síntese de mediadores inflamatórios por macrófagos estimulados com lipopolissacarídeo bacteriano (LPS). O gel de papaína foi diluído nas concentrações de 0,5 e 5%. Células indiferenciadas da polpa dentária OD-21 e macrófagos J774.1 foram mantidos em cultura com os diferentes estímulos por um período de estimulação de 24 h para realização do teste de citotoxicidade (Ensaio LDH) e para avaliação da viabilidade celular (Ensaio Colorimétrico MTT). A seguir foi realizada avaliação da expressão gênica relativa dos genes Ibsp, Runx2 e Spp1 em células OD-21; e dos genes Il10, Mmp9, Ptgs2 e Tnf em células J774.1, pelo método de transcrição reversa e reação em cadeia de polimerase em tempo real (qRT-PCR), após estimulação pelo período de 24 h. O extrato do gel diluído a 5% foi citotóxico às células da polpa dental, reduziu a viabilidade celular, inibiu a expressão de Runx2 e Ibsp e estimulou a expressão de Spp1. Em macrófagos, o extrato do gel foi citotóxico e reduziu a viabilidade celular na concentração de 5%. O LPS inibiu a viabilidade celular na presença ou não do extrato do gel, sem apresentar citotoxicidade. O extrato do gel induziu a expressão de Ptgs2 e Il10, sem alterar Tnf e Mmp9. O extrato do gel de papaína foi citotóxico, dependente da concentração, tanto em células da polpa dentária como em macrófagos, sem alterar a viabilidade celular. Interessantemente, apresentou efeito inibitório na diferenciação de células da polpa dentária e modulou a ativação de macrófagos estimulados com LPS. No tecido pulpar, o Papacárie Duo® poderia impedir a dentinogênese de reparação, porém ativar macrófagos para desempenhar seu papel na inflamação e defesa.

Influence of Cavity Dimensions on Microleakage of Two Bulk-Fill Composite Resins

Objective: To evaluate the effect of cavity dimensions on the amount of microleakage in two different types of bulk-fill composite resins. Material and Methods: Forty class II cavities were prepared in the mesial and distal surfaces of human molars without any carious lesions. The samples were divided into 4 groups (n=10): Group 1: cavities with 3 mm of buccolingual width (known as the smaller cavity), filled with Tetric N-Ceram Bulk Fill composite resin; Group 2: cavities with 6 mm of buccolingual width (larger cavity), filled with Tetric N-Ceram Bulk Fill composite resin; Group 3: cavities with 3 mm of buccolingual width, filled with X-Tra Base composite resin; and Group 4: cavities with 6 mm of buccolingual width, filled with X-Tra Base composite. After the specimens were thermocycled for 500 cycles at 5/55°C, they were immersed in 1% methylene blue for 24 hours, and then cut into sections mesiodistally in the longitudinal axis of each tooth. Then, the samples were scored regarding the amount of dye penetration in two occlusal and gingival areas under a stereomicroscope (x32). Data was submitted to Kruskal- Wallis and Mann-Whitney tests. Results: The highest degrees of microleakage in larger cavities filled with X-Tra Base among the four groups. There was a significant statistic difference (p=0.012) between large and small cavities filled with X-Tra Base (Groups 3 and 4); however, there was no significant difference between the two cavity sizes of Tetric N-Ceram Bulk-filled groups. Conclusion: Microleakage of composite resins depends on the dimension of the cavity and the type of composite resin used.

Assessment of a conservative approach for restoration of extensively destroyed posterior teeth

Abstract Extensive restorations in posterior teeth always bring doubts to the clinicians regarding the best protocol, mainly when structures of reinforcement were lost. Objective This study aimed to evaluate the effect of beveling on the fracture resistance and pattern of class II (MOD) restored teeth. Methodology Ninety human premolars were randomly assigned into 9 groups: CTR (control/sound); NC (cavity preparation, non-restored); RU (restored, unbeveled); RTB (restored, entire angle beveling); RPB (restored, partial/occlusal beveling); EC (endodontic access/EA, non-restored); EU (EA, unbeveled); ETB (EA, entire angle beveling); EPB (EA, partial/occlusal beveling). Teeth were restored with Esthet X resin composite and stored in distilled water for 24 h before the inclusion in PVC cylinders. The axial loading tests were performed with 500 kgF at 0.5 mm/min crosshead speed until fracture of the specimens. Fracture resistance and pattern were accessed and data were analyzed using one-way ANOVA and Tukey's HSD test (α=0.05). Results Mean (±SD) failure loads ranged from 136.56 (11.62) to 174.04 (43.5) kgF in the groups tested without endodontic access. For endodontically accessed teeth, fracture resistance ranged from 95.54 (13.05) to 126.51 (19.88) kgF. Beveling of the cavosurface angle promoted the highest fracture resistance values (p<0.05) and prevented catastrophic fractures. Conclusions Cavosurface angle beveling is capable of improving fracture resistance and pattern for both endodonticaly accessed and non-accessed teeth.

Análisis del cierre marginal en incrustaciones de cerámicas preformadas / Analysis of the marginal closure of preformed ceramic inlays

El propósito de este trabajo fue analizar el cierre marginal de restauraciones semipermanentes de porcelanas para método directo. Para la metodología, se utilizó un diseño experimental verdadero transversal pues se basó en variables con única medición. Los grupos se conformaron al azar. Las unidades de análisis fueron los sistemas adhesivos y el medio de fijación. Las preparaciones de las muestras se basaron en la norma ISO 11405 tanto para la mantención, confección, número de muestras y valoración. La variable utilizada fue la presión ejercida durante la polimerización del medio de fijación. Para la realización de este trabajo se realizó el análisis colorimétrico a través de la penetración de un colorante en las interfases medio de fijación diente o medio de fijación porcelana; y el análisis microscópico de las interfases producidas entre el sistema adhesivo - medio cementante y material de restauración rígida (AU)

The purpose of this work was to analyze the marginal closure of semi-permanent ceramic restorations for direct method. For the methodology, a true cross-section experimental design was used because it was based on variables with only measurement. The groups were formed randomly. The units of analysis were the adhesive systems and the fixing medium. The sample preparations were based on ISO 11405 standard for both maintenance, preparation, number of samples and assessment. The variable used was the pressure exerted during the polymerization of the fixing medium. In order to carry out this work, the colorimetric analysis was carried out through the penetration of a dye in the interfaces between the teeth or the porcelain fixation medium; and the microscopic analysis of the interfaces produced between the adhesive system - cementing medium and rigid restoration material (AU)

Effect of dentin preparation mode on the bond strength between human dentin and different resin cements

Abstract The aim was to evaluate the influence of different dentin preparation mode in the smear layer characteristics (SL), hybrid layer (HL), and microtensile bond strength (µTBS) to dentin with two resin cements. The occlusal dentin of 120 third molars was exposed. The teeth were divided into 4 groups (n=30) according to the dentin preparation mode: 1- fine grain diamond bur; 2- coarse grain diamond bur; 3- multi laminate carbide steel bur; and, 4- ultrasonic CV Dentus diamond bur. Each treated dentin group was divided into 2 sub-groups (n=15) according to the resin cement: (1) RelyX U200 and (2) RelyX ARC. Resin composite blocks were cemented on dentin. After storage at 37o C for 24 h, beams with a cross section area of 1.0 mm2 were obtained, and tested in a universal testing machine at a crosshead speed of 0.5 mm/min. Two additional teeth for each sub-group were prepared to analyze the SL and HL on a scanning electron microscopy. According to Kruskal-Wallis test and Dunn tests, there was no significant difference in µTBS among the rotary instruments within each resin cement group. RelyX ARC obtained higher µTBS values compared to RelyX U200 (p<0.05). RelyX ARC formed evident HL, which was not observed for RelyX U200. The dentin mode preparation did not influence the µTBS of the resin cements. The SL was different for all instruments. The cementing agent is more determinant in the hybrid layer formation and bond strength to dentin than the instruments applied on dentin.

Resumo O objetivo deste estudo foi avaliar a influência de diferentes modos de preparação da dentina nas características da smear layer (SL), da camada híbrida (CH) e na resistência de união à microtração (RUµT) à dentina com dois cimentos resinosos. A dentina oclusal de 120 terceiros molares humanos foi exposta. Os dentes foram divididos em 4 grupos (n=30) de acordo com o modo de preparação da dentina: 1 - ponta diamantada de granulação fina; 2 - ponta diamantada de granulação grossa; 3 - ponta de carboneto de aço multilaminada; 4 - ponta diamantada ultrassônica. Cada grupo foi subdividido em dois subgrupos (n=15) de acordo com o cimento resinoso: (1) RelyX U200 e (2) RelyX ARC. Blocos de resina composta foram cimentados na dentina. Após armazenamento a 37 °C por 24 h, as amostras foram cortadas para obter palitos com área de 1,0 mm2, os quais foram testados em máquina de ensaio universal com velocidade de 0,5 mm/min. Dois dentes adicionais por subgrupo foram preparados para analisar as características da SL e da CH em microscópio eletrônico de varredura. De acordo com o teste de Kruskal-Wallis e o teste de Dunn, não houve diferença significativa na RUµT entre os instrumentos rotatórios para cada cimento resinoso. RelyX ARC obteve maiores valores de RUµT em comparação ao RelyX U200 (p<0,05). RelyX ARC formou uma CH evidente, o que não foi observado para o RelyX U200. O modo de preparação da dentina não influenciou na RUµT dos cimentos resinosos. A SL foi diferente para todos os instrumentos. O agente de cimentação foi mais determinante na formação da camada híbrida e na resistência de união do que os instrumentos utilizados para preparar a dentina.