Bisphenol A released and ultrastructural changes in dental composite resins

Dental composite resins may release bisphenol-A or similar molecules affecting patient health and the environment. This study measured bisphenol-A release from three commonly used in patients composite resins (Filtek™ Z350 XT, Filtek™ P60, Filtek™ Bulk Fill) immersed in three liquid mediums (artificial saliva, 0.001 M lactic acid and 15% ethanol) and assessed the changes in the surface micromorphology.The released BPA was measured by HPLC at basal time (t=0), 1 h, 1 d, 7 d and 30 d. Topographic analysis of specimens was performed by scanning electron microscopy (SEM). The data were analyzed using one-way ANOVA and Tukey post-hoc test (P < 0.05). BPA in solution increased significantly in the three DCRs immersed in 0.001 M lactic acid at all times. SEM micrographs of the specimen in 0.001 M lactic acid disclosed more structural defects than others. The surface of the three composite resins was morphologically affected by their immersion in all solutions. SEM evidenced that the dental materials underwent erosion and cracks with filler particles protruding from the surface. The morphological changes in tested dental materials produced by exposure to these solutions are potentially dangerous to patients by causing caries, infections, and partial loss of dental material.

Comparative study on radio-opacity of dental composite resin materials'determination using film imaging and digital imaging / 北京大学学报(医学版)

OBJECTIVE@#To compare the effects of different imaging methods on radio-opacity. Digital imaging and traditional film imaging were used to determine the radio-opacity of dental composite resin materials.@*METHODS@#Fourteen dental composite resins commonly used in clinic were prepared for disc samples with thickness of 1 mm and diameter of 15 mm respectively. The aluminum step wedge was used as the reference and the disc samples were irradiated with X-rays by the traditional film imaging, phosphor imaging plate and charge-coupled device(CCD) intra-oral X-ray sensor respectively. Exposure was set at 65 kV and 7 mA, with 300 mm focus to film distance and the exposure time was 0.25 s. After developing and fixing the film, the optical density of the image of the sample and that of each step of the aluminum step wedge were measured using the densitometer. The digital image file was exported to grey scale analysis software of Adobe Photoshop® to measure the average grey value in the sample image and aluminum step wedge image. The curves were drawn corresponding to the optical density/gray value of each step of the aluminum step wedge and its thickness, and the equivalent thickness of the aluminum plate was calculated according to the optical density/gray value of the actual measured thickness of the sample, so as to evaluate the radio-opacity of dental composite resin material.@*RESULTS@#For the same sample, the aluminum equivalent measured by traditional film imaging and two other digital imagings had significant differences among the 14 composite resins (P < 0.05), and the aluminum equivalent measured by the two digital imagings were greater than that of the traditional film. Moreover the aluminum equivalent measured by the two digital imagings was also different, and the aluminum equivalent measured by the CCD intra-oral X-ray sensor in most composite resins was larger than that measured by phosphor imaging plate. The same sample was photographed with the same imaging method, and the aluminum equivalent was different after three exposures. The standard deviation of aluminum equivalent measured by phosphor imaging plate was the largest, while that measured by CCD intra-oral X-ray sensor was the smallest. Among the 14 dental composite resin materials, the aluminum equivalent of Tetric N-Ceram and Te-Econom Plus measured by traditional film imaging and phosphor imaging plate was significantly higher than other composite resins.@*CONCLUSION@#Based on clinical significance, three kinds of sensors designed to measure the radio-opacity of dental composite resin, the value of aluminum equivalent will change according to different types of sensors. The aluminum equivalent measured by CCD intra-oral X-ray sensor was higher than that measured by phosphor imaging plate, and the aluminum equivalent measured by phosphor imaging plate was higher than that measured by traditional film imaging. Moreover, even though the same sensor was used, the aluminum equivalent measured by multiple exposures was different. The standard deviation of the aluminum equivalent measured by phosphor imaging plate was greater than that measured by traditional film imaging and CCD intra-oral X-ray sensor. The three sensors in this study could be used for evaluating the radio-opacity of dental composite resin materials. But no matter what kind of sensor was used to measure the radio-opacity of dental composite resin, it complied to ISO 4049: 2019 standard, the materials were suitable for clinical use.

Recomendaciones para el empleo práctico de resinas compuestas en restauraciones estéticas / Recommendations for the use of composite resins in esthetic restorations

Introducción: la población, solicita con frecuencia restauraciones compatibles con los estándares de la estética dental y ello en ocasiones se dificulta dada la diversidad de materiales restauradores existentes y técnicas para su aplicación. Objetivo: proponer recomendaciones para el empleo práctico de las resinas compuestas fotopolimerizables en restauraciones estéticas de dientes anteriores y posteriores. Métodos: se realizó un estudio de revisión bibliográfica sobre técnicas para el empleo de resinas compuestas en restauraciones estéticas. Esto se llevó a cabo a través de Scopus, SciELO, Hinari, Medline y 45 revistas científicas indexadas de manera manual. El estudio se circunscribió a 89 artículos y 3 libros que enfocaron esta temática de manera más integral. Se reagruparon todos los documentos revisados y se procesaron según revista científica de origen y año de publicación. Integración de la información: las recomendaciones incluyeron la valoración individual de la estética del paciente, selección del tipo de resina a emplear, selección del color, profilaxis y pulido de la superficie de trabajo, preparaciones cavitarias con o sin confección de biseles, protección o no del complejo dentino pulpar, grabado ácido, lavado y enjuague del ácido grabador, aplicación del adhesivo, inserción y manipulación de la resina compuesta, polimerización y acabado de la restauración. Consideraciones finales: los tratamientos curativos y estéticos son muy variado en el campo de las resinas compuestas fotopolimerizables, por lo cual resulta útil seguir, entre otras, las recomendaciones de realizar limpieza de la superficie de trabajo, seleccionar el color y tipo de resina indicados en cada caso, realizar preparaciones cavitarias mínimas con biseles (si es necesario), emplear incrementos en la realización de las restauraciones, polimerizar evitando grandes reacciones de contracción, y pulir adecuadamente las restauraciones(AU)

Introduction: patients often request the performance of restorations compatible with the standards of dental esthetics. This is sometimes hampered by the great variety of restoring materials and techniques for their application. Objective: propose recommendations for the use of photopolymerizable composite resins in esthetic restorations of anterior and posterior teeth. Methods: a bibliographic review was performed about techniques for the use of composite resins in esthetic restorations. The search was conducted in the databases Scopus, SciELO, Hinari and Medline, as well as 45 manually indexed scientific journals. The reviewers selected the 89 papers and 3 books which approached the topic in a more comprehensive manner. All the documents reviewed were arranged and processed by scientific journal and year of publication. Data integration: recommendations included the following topics: individual assessment of the patient's esthetic considerations, selection of the resin type to use, selection of color, prophylaxis and polishing of the work surface, cavity preparation with or without beveling, protection or not of the dentin-pulp complex, acid engraving, washing and rinsing of the engraving acid, application of the adhesive, insertion and manipulation of the composite resin, polymerization and finishing of the restoration. Final considerations: there is a great variety of curative and esthetic treatments based on the use of photopolymerizable composite resins. Therefore, it would be advisable to follow these recommendations, among others: clean the work surface, select the appropriate resin color and type, perform as few beveled cavity preparations as possible (only if required), apply increments while carrying out the restoration, polymerize avoiding great contraction reactions, and polish the restorations appropriately(AU)

Análisis comparativo in vitro del grado de filtración marginal de restauraciones de resina compuesta realizadas con dos métodos de grabado ácido distintos / In vitro comparative analysis of microleakage in composites resin restorations made with a conventional and a modified acid etch technique

La técnica de grabado ácido en esmalte representa el hito que marca la puerta de entrada para el establecimiento de la odontología adhesiva. Producto de que el sustrato adamantino pudiese presentar comportamiento refractario a la técnica convencional de grabado ácido es que se plantea una técnica en dos tiempos operatorios, la cual pudiese disminuir dicho comportamiento resistente al grabado ácido y combatir así el fenómeno de la filtración marginal de las resinas compuestas. En este estudio se utilizaron 30 terceros molares sanos, en los cuales se realizaron cavidades clases V en las caras vestibulares y linguales/palatinas, las cuales fueron obturadas con resina compuestas utilizando técnica de grabado ácido convencional y técnica de grabado ácido en dos tiempos operatorios, respectivamente. Estos especímenes fueron sometidos a un proceso de termociclado en presencia de un agente colorante marcador. Luego de un proceso de termociclado, las muestras fueron cortadas transversalmente para evaluar el porcentaje de penetración del agente marcador. El análisis de los resultados demostró que las restauraciones realizadas con técnica de grabado ácido en dos tiempos operatorios presentaron menores valores de filtración marginal, existiendo diferencias significativas entre ambos grupos estudiados.

The acid etch technique is the fact that marks the starting point for the establishment of the adhesive dentistry era. But as the enamel structure may have a resistant behavior towards the conventional acid etch technique ,a two-step acid etch technique is presented. This would diminish the aforementioned resistant behavior of enamel to the conventional acid etch technique, and minimize as well, the marginal leakage phenomenon of the composite materials. In this study 30 sound recently extracted molars were used. Equal class V cavities preparations were made in the buccal and palatal/lingual faces of each tooth. Buccal cavities were filled with composite before the use of the conventional acid etch technique, as adhesive method, while in the lingual/palatal faces the two-step acid etch technique was used. The samples were subjected to thermal cycles in the presence of a dying agent. After the thermocycling process, the samples were cut transversely to assess the percentage of penetration of the staining agent. The analysis of the results showed that there was a significant statistical difference between both groups. Moreover the restorations made with the two-step acid etch technique presented lower values of marginal leakage.