Effect of indirect composite treatment microtensile bond strength of self-adhesive resin cements

Background: No specific indications about the pre-treatment of indirect composite restorations is provided by the manufacturers of most self-adhesive resin cements. The potential effect of silane treatment to the bond strength of the complete tooth/indirect restoration complex is not available.The aim of this study was to determine the contribution of different surface treatments on microtensile bond strength of composite overlays to dentin using several self-adhesive resin cements and a total-etch one. Material and Methods: Composite overlays were fabricated and bonding surfaces were airborne-particle abraded and randomly assigned to two different surface treatments: no treatment or silane application (RelyX Ceramic Primer) followed by an adhesive (Adper Scotchbond 1 XT). Composite overlays were luted to flat dentin surfaces using the following self-adhesive resin cements: RelyX Unicem, G-Cem, Speedcem, Maxcem Elite or Smartcem2, and the total-etch resin cement RelyX ARC. After 24 h, bonded specimens were cut into sticks 1 mm thick and stressed in tension until failure. Two-way ANOVA and SNK tests were applied at α=0.05. Results: Bond strength values were significantly influenced by the resin cement used ( p <0.001). However, composite surface treatment and the interaction between the resin cement applied and surface treatment did not significantly affect dentin bond strength ( p >0.05). All self-adhesive resin cements showed lower bond strength values than the total-etch RelyX ARC. Among self-adhesive resin cements, RelyX Unicem and G-Cem attained statistically higher bond strength values. Smartcem2 and Maxcem Elite exhibited 80-90% of pre-test failures. Conclusions: The silane and adhesive application after indirect resin composite sandblasting did not improve the bond strength of dentin-composite overlay complex. Selection of the resin cement seems to be a more relevant factor when bonding indirect composites to dentin than its surface treatmen

Dental emergency care in Spain during the state of alarm due to COVID-19 pandemic

The first state of alarm due to COVID-19 in Spain led to limit dental treatment exclusively to emergencies. The objective of the survey was to evaluate the amount and type of emergencies attended during this period, as well as to know how they were solve

Resistencia mecánica de la interfase y de la dentina adyacente. Estudio comparativo de microtracción // Micro-tensile bond strength of the interface of an adhesive restorative system

Introducción: se describe y aplica un sistema de microtracción, que permite comparar las fuerzas de resistencia a la tracción de la dentina intacta y las de la interfase adyacente creada entre dentina y material restaurador, dentro de un mismo espécimen. Material y método: se emplearon segmentos coronarios de terceros molares humanos conectados a un sistema de perfusión (n=12), sobre los que se tallaron varios surcos paralelos en la dentina oclusal que fueron posteriormente obturados con el adhesivo Prime & Bond NT® y los composites Z100® y Tetric Ceram®. Se obtuvieron cinco muestras preparadas para microtracción por espécimen que se sometieron a ensayo mecánico hasta su rotura. Resultados: se encontraron diferencias estadísticamente significativas entre la fuerza cohesiva media de la dentina y la adhesiva de las interfases diente/material restaurador, para ambos sistemas restauradores. No hubo diferencias estadísticaemnte significativas entre ambos materiales de restauración utilizados con el mismo adhesivo. Conclusión: la fuerza de cohesión de la dentina supera a la de la interfase diente/material en los materiales estudiados. // Introduction: a microtensile test is developed in order to compare the tensile bond strength of sound dentine and those of the adyacent interface between dentine and restorative materials, within the same specimen. Material and method: on the occlusal exposed dentin of perfused third molars crown segments (n=12) several grooves were cut, which later were filled with Prime & Bond NT adhesive and Z100 and Tetric Ceram composites. Five samples for microtensile test were obtained from each specimen and were submittes to load until detachment. Results: significant statistical differences were found among mean cohesive dentin strength and the interface dentin/restorative material adhesive strength, for both restorative materials used with the same adhesive resin. Conclusions: dentin cohesive strength is higher than dentin/restorative material interface for the materials tested

El sellado de la amalgama adherida "versus" otros materiales de restauración

Introducción: estudio comparativo in vitro de la capacidad de sellado entre restauraciones de amalgama adherida, de resina compuesta y resina compuesta modificada con vidrio ionomero. Material y método: se usaron 175 molares humanos conectados a un sistema de presión simulada (32 cm de agua destilada), determinándose la consductancia hidráulica de cada espécimen tras ser obturados con cada uno de los distintos materiales de estudio. Resultados: los resultados evidencian que la condustancia de los especímenes restaurados con amalgama adherida es menor que la obtenida con el resto de los materiales, sobre todo con F2000 y Dyract. Conclusiones: las restauraciones de amalgama adherida reducen la permeabilidad en mayor grado que los materiales a base de resina compuesta modificada, aunque ninguno de los materiales detiene por completo la filtración. // Introduction: the present article is a comparative in vitro study of the sealing ability of bonded amalgams versus glass-ionomer modified composite resins and composite resin restorations. Materials and methods: 175 human molars were connected to a simulated pressure system (32 cm of distilled water). The hydraulic conductance of each sample was determines after being resored with each one of the different materials tested. Results: results show less residual hydraulic conductance in samples restored with bonden amalgam than in samples with the rest of materials tested, specially with F2000 and Dyract. Conclusions: in those samples restored with bonden amalgam permeability is reduced to a higher extend than in samples restored with resin modified glass-ionomers. None of material stopped filtration through dentin completely