Dinámica de polimerización enfocada a reducir o prevenir el estrés de contracción de las resinas compuestas actuales. Revisión bibliográfica / Dynamics of polymerization focused on reducing or preventing the stress of contraction of the current composite resins. Bibliographic review

En los últimos años, las resinas compuestas han sido mejoradas en cuanto al desgaste, estética y otras propiedades físicas. El mayor problema que persiste con las resinas compuestas es que estos materiales se contraen durante la polimerización. Contracción significa densificación o pérdida de volumen. En la cavidad dental, esta pérdida de volumen compromete la integridad de la interfase entre resina y diente, lo cual favorece la formación de grietas con el riesgo de hipersensibilidad, recidiva de caries o, incluso, fractura de la restauración. En el presente artículo, se expone la actualidad acerca del conocimiento sobre la contracción de polimerización de las resinas compuestas y su relación con el tipo de lámpara de polimerizar. Así mismo, se desarrollan los conceptos de fase obscura, expansión higroscópica, el consecuente estrés de contracción o los nuevos materiales que se presumen carentes de contracción; todo ello, en el marco de la dinámica lógica y normal llevada a cabo a la hora de realizar una obturación utilizando resinas compuestas con independencia de su relleno o partícula de éste. Respecto a las fuentes de polimerización, tanto las lámparas halógenas convencionales o las de alta densidad de potencia, como las LEDs, ofrecen un incremento gradual de la intensidad lumínica, lo que resulta muy útil para disminuir la contracción volumétrica del material

In recent years, composite resins have been improved in terms of wear, aesthetics and other physical properties. The major problem persists with composite resins is that these materials shrink during polymerization. Contraction means densification or loss of volume. In the dental cavity this loss of volume compromises the integrity of the interface between resin and tooth, which favors the formation of cracks with the risk of hypersensitivity, recurrence of caries or even fracture of the restoration. This article presents the current knowledge about the polymerization contraction knowledge of the composite resins and its relation to the type of polymerization lamp. Also the concepts of obscure phase, hygroscopic expansion, the consequent stress of contraction or the new materials that are presumed devoid of contraction are developed, all this in the frame of the logical and normal dynamics carried out at the time of making a seal using composite resins, regardless of their filler or particle thereof. Regarding the sources of polymerization, both conventional halogen lamps and high power density lamps, such as LEDs, offer a gradual increase in light intensity, which is very useful to decrease the volume shrinkage of the material

Estabilidad marginal de una resina condensable versus resina monoincremental activada sónicamente en restauraciones clase II: Estudio in vitro / Marginal stability of a condensable resin versus a bulk-fill resin with sonic activation in class II restorations: An in vitro study

Introducción: Recientemente se han introducido las resinas bulk-fill, las cuales pueden ser utilizadas con técnica monoincremental, disminuyendo el tiempo clínico y ofreciendo una técnica menos sensible. El objetivo de este estudio es evaluar la estabilidad marginal de una resina compuesta condensable, utilizando técnica incremental oblicua versus una resina monoincremental con activación sónica en restauraciones clase II. Materiales y método: A 16 terceros molares sanos se les realizó dos preparaciones cavitarias clase II. Las dimensiones de las preparaciones fueron estandarizadas: 3 mm de ancho vestibulolingual, 2 mm de profundidad y 1,5 mm en sentido mesiodistal para el cajón oclusal, y 3 mm de ancho vestibulolingual, 4 mm de profundidad y 1,5 mm en sentido mesiodistal para el cajón proximal, determinándose al azar restaurar una preparación con resina condensable FiltekTM P60 (3M(R) ESPE-USA) utilizando técnica incremental, y la segunda preparación con resina SonicFillTM (Kerr-USA) con técnica monoincremental y activación sónica. Las muestras se termociclaron en azul de metileno al 1%, se cortaron en sentido mesiodistal y analizaron mediante microscopio óptico. Se cuantificó el grado de penetración del agente infiltrador en el margen cavosuperficial oclusal y gingival de ambas resinas. Se realizó un test exacto de Fisher y posterior U de Mann-Whitney. Resultados: La profundidad de infiltración del borde cavosuperficial gingival fue significativamente menor para FiltekTM P60 comparado con SonicFillTM (p= 0,028). Discusión: Ambas técnicas presentaron valores similares de estabilidad marginal en el borde cavosuperficial oclusal, sin embargo la resinas FiltekTM P60 presenta una mayor estabilidad marginal en el borde cavosuperficial gingival (AU)

Introduction: Recently, bulk-fill resin shave been introduced, which can be used with a mono-incremental technique, shortening clinical time and offering a less sensitive technique. The purpose of this study was to evaluate the marginal stability of condensable composite resins by using incremental technique versus a bulkfill resin with sonic activation. Material and method: Two Black’s class II cavities preparations were performed on 16 healthy third molars. The overall dimensions and depth of cavities were standardized as follows: 3 mm wide, 2 mm deep and 1,5 mm of mesiodistal lenght at the occlusal box, and 3 mm wide, 4 mm deep and 1,5 mm of mesiodistal length at the proximal box. It was randomly determined to restore a preparation with condensable resin FiltekTM P60 (3M(R) ESPE-USA) using oblique incremental technique, while these cond preparation used SonicFillTM resin (Kerr- USA) with mono-incremental technique and sonic activation. These were thermocycled in methylene blue 1%, then cut in mesio-distal sense and analysed by optical microscope. The degree of penetration of the infiltrator agent in the oclusal cavosurface margin and gingival wall of both resins was measured. Fisher’s exact test and a subsequent Mann-Whitney U test were performed. Results: The amount of infiltration in gingival cavosurface margin was significantly lower for Filtek™ P60 compared with SonicFillTM (p= 0.028). Discussion: Both techniques presented similar values of marginal stability in the oclusal cavosurface margin, however, resinFiltekTM P60 has greater stability in the gingival cavosurface margin (AU)

Comportamiento del color de discos y restauraciones en resina compuesta sometidos a altas temperatura con fines forenses / Performance of color of discs and restorations in composite resin subject to high temperatures to forensic purposes

El objetivo de este estudio fue determinar el comportamiento del color de discos y restauraciones en resina compuesta sometidos a altas temperaturas con fines forenses. Para ello se realizó un estudio descriptivo de naturaleza pseudoexperimental in vitro que describió los cambios colorimétricos que ocurrieron en 75 discos y 75 dientes restaurados en resina compuesta (Z100 3M-ESPE®), confeccionados en cinco colores (A1, A2, A3, A3.5 y B2), al ser sometidos a la acción de altas temperaturas, con el propósito de establecer parámetros cualitativos a partir del cambio de color de utilidad forense. Los resultados obtenidos permitieron explicar los cambios de color por espectrometría, de tal forma que una resina compuesta, a 200 oC, pierde brillo y matiz; a 400 oC, pierde brillo, matiz y saturación; y a 600 oC, 800 oC y 1.000 oC gana brillo y pierde matiz y saturación. Así, no existieron diferencias significativas en las coordenadas de color L* a* b* al comparar los discos con los dientes restaurados. En conclusión, la interpretación visual del cambio de color y las coordenadas de color L* a* b* a través del uso de un espectrofotómetro puede constituirse en un método comparativo de bajo costo y de aplicación forense al momento de identificar el tipo y el color de un material restaurador en un cadáver o en restos humanos quemados, carbonizados o incinerados, para obtener marcadores positivos durante el cotejo ante mórtem-post mórtem, y estimar la temperatura máxima alcanzada durante la exposición (AU)

The objective for this study was to determine the color behavior of discs and composite resin restorations subjected to high temperature for forensic purposes. For this, a descriptive study of pseudo-experimental nature was made, to describing in vitro colorimetric changes that occur on the surface of 75 disks and 75 class I composite resin restorations (Z100 3M-ESPE®) made in five colors (A1, A2 , A3, A3.5 and B2), when subjected to the action of high temperatures (200 oC, 400 oC, 600 oC, 800 oC y 1,000 oC); in order to set parameters from the color change that can be applied to the forensic dental identification methods in the case of bodies or human remains burnt, charred or incinerated. The color changes can be explained by spectrometry. A composite resin subjected to 200 oC loses brightness and hue; to 400 oC wins brightness, hue and saturation; to 600 oC, 800 oC and 1,000 oC lost brightness, hue and saturation. No significant differences in the color coordinates L * a * b * to compare discs with the restored teeth, so the test bodies were suitable to test with the commercial composite resin system ESPE® 3M-Z100. In conclusion, the visual interpretation of color change and the L * a * b * color coordinates through the use of a spectrometer becomes a comparative forensic method application inexpensive when identifying the type and color a restorative material in a human remains burnt, charred or incinerated, to obtain positive markers for the antemortem-postmortem comparison and estimate the maximum temperature reached (AU)

Evaluación de la adaptación interna de resinas compuestas: Técnica incremental versus bulk-fill con activación sónica / Internal adaptation evaluation of composite resins: Incremental filling versus Sonic-activated bulk-fill

Introducción: Recientemente se han desarrollado las resinas bulk-fill que pueden ser utilizadas con técnica monoincremental, reemplazando la tradicional técnica incremental oblicua y acortando el tiempo clínico. El objetivo de este estudio es evaluar la adaptación de las resinas compuestas a las paredes internas cavitarias, utilizando técnica incremental oblicua y monoincremental con activación sónica. Material y método: Se utilizaron 15 terceros molares sanos, a los cuales se les realizó dos preparaciones cavitarias clase II con márgenes en esmalte, de dimensiones en sentido mesiodistal de 3 mm, vestibulolingual de 2,5 mm, profundidad oclusopulpar de 2 mm y profundidad oclusoproximal de 4 mm. Las preparaciones distales se restauraron utilizando la resina convencional FiltekTM Z350 XT con técnica incremental y las mesiales con la resina bulk-fill SonicFillTM con técnica monoincremental y activación sónica. Las muestras fueron cortadas en sentido mesiodistal y analizadas mediante microscopio óptico a aumento de 10× y 40×. Se midió el porcentaje de adaptación de ambas resinas y se realizó un test ANOVA de dos vías con prueba post hoc de Tukey. Resultados: No se encontró diferencia estadísticamente significativa en la adaptación interna cavitaria utilizando la técnica monoincremental con activación sónica y la incremental oblicua (p>0,01). Discusión: La técnica monoincremental con activación sónica, a pesar de tener un menor tiempo en el mercado, menor tiempo de entrenamiento clínico y menor consumo de tiempo clínico presentó valores similares de adaptación a las paredes internas cavitarias que la técnica incremental oblicua (AU)

Introduction: Recently, Bulk-Fill resins have been developed and they can be used with a mono-incremental technique, eliminating the traditional oblique incremental technique and shortening the clinical time. The aim of this study is to evaluate the internal adaptation of composite resins using oblique incremental and monoincremental techniques with sonic activation. Material and method: 15 healthy third molars were used and two enamel finished class II cavity was performed on each one of them. Dimensions were: 3 mm mesio-distal, 2.5 mm buccal-lingual, 2 mm occlusal-pulp depth, and 4 mm occlusal-proximal depth. The distal preparations were restored using a conventional FiltekTMZ350 XT (3M ESPE, USA) resin with oblique incremental technique and the mesial ones were restored using Bulk-Fill SonicFillTM (Kerr, USA) resin through mono-incremental technique and sonic activation. The samples were cut in a mesiodistal direction and analyzed with an optical microscopy at 10× and 40× magnification. The percentage of adaptation of both resins was measured, and a two-way ANOVA with Tukey correction was performed. Results: No statistically significant difference was found in the adaptation of both resins, using oblique incremental and mono-incremental techniques with sonic activation (p>0.01). Discussion: Both techniques reported similar values of adaptation, therefore, the mono-incremental technique with sonic activation is a recently introduced technique, which seems to be less sensitive than oblique incremental technique (AU)

Cytotoxic effect of silorane and methacrylate based composites on the human dental pulp stem cells and fibroblasts

OBJECTIVES: The aim of this study was to compare the cytotoxic effect of a methacrylate-based and a siloranebased composite on the human dental pulp stem cells (DPSCs) versus human dental pulp fibroblasts (DPFs).Study DESIGN: Samples of the Filtek Z250 and P90 were polymerized and immersed in the culture medium to obtain extracts after incubation for one, seven and 14 days. Magnetic cell sorting based on the CD146 expression was performed to purify DPSCs and DPFs. After incubation of both cells with the extracts, cytotoxicity was determined using the MTT test. RESULTS: For the extracts of first and seventh day, both composites showed significantly lower cytotoxicity on DPSCs than DPFs (p = 0.003). In addition, there was a significant difference in the time-group interaction of both materials indicating different cytotoxic behaviours (p = 0.014). In contrast to Z250, exposure to the 14th day extract of P90 resulted in higher cell viability compared to that of day seven. CONCLUSIONS: DPSCs are less susceptible to the cytotoxic effect of the composites than DPFs. Compared to Z250, the cytotoxic effect of silorane-based composite decreases as the time passes on. This difference should be considered, particularly in deep cavities, in order to preserve the regenerative capacity of the pulp

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Efectos genotóxicos de las resinas en odontología: Revisión de literatura / Genotoxic effect of composites resins in dentistry: A review

Objetivo: Analizar la evidencia científica disponible acerca de la genotoxicidad causada por los monómeros dentales liberados de las resinas compuestas. Materiales y métodos: Se lleva a cabo una búsqueda electrónica exhaustiva de estudios relacionados con la genotoxicidad de las resinas compuestas o los monómeros dentales utilizando las bases de datos Pubmed, OvidSP, EbscoHost, SciVerse y SpringerLink. Se revisaron un total de 115 artículos y se seleccionaron 36 entre estudios clínicos controlados, estudios en animales y pruebas in vitro. Conclusiones: La exposición a los monómeros residuales liberados por las resinas compuestas, causa gran preocupación por los estudios que advierten su potencial genotóxico. El principal mecanismo es atribuido al estrés oxidativo que se genera por aumento de las concentraciones de radicales libres y disminución de los niveles de glutatión, agente responsable del balance redox en la célula. Estas alteraciones conllevan a la activación de varias vías de apoptosis celular y retrasos en las fases G1 y G2 del ciclo celular (AU)

Objective: To examine the available scientific evidence about the genotoxicity caused by monomers released from dental composite resins. Materials and methods: We carried out a comprehensive electronic search of studies related to the genotoxicity of composite resins or dental monomers using the databases PubMed, OvidSP, EBSCOhost, and SciVerseSpringerLink. We reviewed a total of 115 articles and 36 were selected from controlled clinical studies, animal studies and in vitro tests. Conclusions: Exposure to residual monomers released from composites, causes great concern about studies that warn their genotoxic potential. The main mechanism is attributed to oxidative stress is generated by increasing concentrations of free radicals and decreased levels of Glutathione redox agent responsible for the cell balance. These changes lead to the activation of multiple pathways of apoptosis and delays in G1 and G2 phases of the cell cycle (AU)

Reconstrucción del diente endodonciado en sector posterior con técnicas adhesivas. Revisión de la literatura / Reconstruction of endodontically treated posterior teeth with modern restorative adhesive procedures. A literature review

Objetivo. Las opciones de tratamiento del diente endodonciado y sus cambios biomecánicos son motivo de controversia. El objetivo de esta revisión es mostrar las alteraciones de composición y estructura de la pérdida de vitalidad pulpar y proporcionar diferentes enfoques restaurativos adhesivos en dientes posteriores para restaurar el diente endodonciado. Método de la revisión. El proceso de búsqueda incluyó una revisión en la base de datos de Pub/Med entre el 1999 y el 2012 usando una serie de palabras clave solas y combinadas. Información relevante y conclusiones. El impacto de la pérdida de vitalidad parece moderado o insignificante en términos de humedad o propiedades físicas. Por el contrario, los cambios más importantes en la biomecánica y la resistencia a la fractura se asocian con un defecto estructural generado por caries, traumatismos o preparación del diente. Por lo tanto, el método más utilizado en la actualidad para la restauración de los dientes no vitales se basa en los preparativos de invasión mínima con la conservación máxima de los tejidos. Técnicas adhesivas y materiales con propiedades físicas próximas a la dentina parecen ser la opción más adecuada. Sin embargo, estudios más clínicos son necesarios para predecir el éxito a largo plazo (AU)

Objective. Biomechanical alterations and treatment options related to endodontically treated teeth are a matter of controversy. The aim of this review is to present the composition and structural alterations resulting from loss of pulp vitality and to provide different approaches to restorative adhesive procedures for anterior endodontically treated teeth. Review method. The basic search process included a review of the PubMed/Medline database between 1999 and 2012 using single or combined key words and a perusal of the references completed the review. Relevant information and conclusions. he impact of vitality loss appears moderate to negligible in terms of moisture or physical properties. Conversely, the most important changes in biomechanics and fracture resistance are associated with structural defect generated by caries, trauma or tooth preparation. Therefore, the most widely used approach at present for restoring nonvital teeth is based on minimally invasive preparations with maximal tissue conservation. Adhesive techniques and materials with physical properties close to natural dentin seem to be the most suitable option. However, more clinical studies are needed to predict a long-term success (AU)

Microleakage in Class II composite restorations with margins below the CEJ: In vitro evaluation of different restorative techniques

OBJECTIVES: The purpose of this in vitro study was to evaluate the microleakage in "deep" Class II composite restorations with gingival cavosurface margin below the CEJ (cemento-enamel junction) and restored with different techniques. STUDY DESIGN: Fifty human teeth were used. In each tooth two standardized Class II slot cavities (on mesial and on distal surfaces) were prepared: the buccolingual extension of the cavities was 4 mm; the gingival wall was located in dentin/cementum (2 mm beyond the CEJ). The prepared teeth were randomly assigned to 5 experimental groups (of 10 specimens and 20 cavities each) and restored. Group 1: Filtek TM Supreme XTE Flowable (3MESPE) + Universal Filtek Supreme XTE (3MESPE), Group 2: GrandioSO Heavy Flow (Voco) + GrandioSo (Voco), Group 3: SDR™ (Dentsply Caulk) + Esthet-X® HD (Dentsply Caulk), Group 4: SonicFill (Kerr), Group 5: Grandio (Voco). After thermocycling, the specimens were immersed in a 0.5% basic fuchsine dye solution and incubated at 37°C for 24 hours. The teeth were subsequently sectioned mesiodistally. All specimens were examined at 25 in a stereomicroscope and standardized digital images were obtained. Dye penetration was measured from gingival margins. RESULTS: The results demonstrated no significant leakage differences between Group 4 and Group 5, that both showed significantly higher frequency distribution of Score 0. Group 2 and Group 3 showed a significant prevalence of Score 1, whereas Group 1 showed significantly higher frequency of Score 2.CONCLUSIONS:None of the restorative techniques tested completely eliminated microleakage dye penetration in dentin margins; marginal adaptation in Class II composite restorations with gingival wall below the CEJ varied in both substrates and from different restorative techniques used (AU)

Three-year clinical performance of two indirect compositeinlays compared to direct composite restorations

Objective: Despite the incremental build-up of resin composite restorations, their polymerization shrinkage during curing presents a serious problem. Indirect composite resin systems represent an alternative in overcoming some of the deficiencies of direct composite restorations. The hypothesis of the present study states that the clinical performance of restorations may be affected by different generation and application techniques. Study Design: Sixty restorations (20 DI system (Coltène/Whaledent AG, Altstätten, Switzerland) composite inlays,20 Tescera ATL system (BISCO Inc. Schaumburg, Illinois, USA) composite inlays, and 20 direct composites)were applied to premolar teeth in 49 patients. Restorations were clinically evaluated by two examiners. Data were analyzed using the Kruskal-Wallis, Mann-Whitney U, Wilcoxon Signed Ranks, and X2 tests. Results: The Tescera ATL system performed significantly better than both direct composite restorations (p<0.001)and DI system (p<0.05).Conclusion: Within the limitations of this 3-year clinical study, indirect resin restorations showed better scores than direct restorations. In addition, the Tescera ATL system was found to be more successful than the DI system and direct composite restorations (AU)

Effect of 15% carbamide peroxide bleaching gel on color stability of giomer and microfilled composite resin: An in vitro comparison

Objectives: The effect of 15% carbamide peroxide bleaching gel on color stability and surface topography of a giomer and a microfilled composite resin was evaluated in the present in vitro study. Study design: Forty discs measuring 10 mm in diameter and 1 mm in thickness were prepared from a giomer and a microfilled composite resin. Each material yielded 20 discs with completely smooth surfaces. Then a spectrophotometer was used to measure L* (lightness), a* (redness, greenness) and b* (blueness, yellowness) color coordinates of all the discs. Subsequently, the specimens were subjected to 15% carbamide peroxide bleaching gel. After measuring the color coordinates once again, color changes (ÄE*) were calculated by the CIELAB system. Six specimens from each material (three specimens before bleaching agent application and three specimens thereafter) were viewed under an atomic force microscope (AFM) for surface topography evaluation. Data were analyzed by Mann-Whitney U and Kruskal-Wallis tests at á=0.05. Results: There were no statistically significant differences in color changes (ÄE*) between the two materials (P>0.05). In addition, no significant differences were detected in surface roughness between composite resin and giomer discs before and after bleaching (P>0.05 for both). However, in both materials the differences in surface roughness were significant before and after bleaching procedures (P<0.001). Conclusions: Based on the results of the present study it was concluded that 15% carbamide peroxide does not induce clinically detectable color changes in composite resin and giomer despite an increase in surface roughness (AU)

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Teaching the placement of posterior resin-based composite restorations in Spanish dental schools

Objectives: In an area of esthetic dentistry such as posterior composites, in which new materials and techniques are being devolved continuously, it is important to confirm that dental students have a clear understanding of the basic principles of clinical application of this knowledge. Considering that the preparation of dental graduates in Spain may be of interest to competent dental authorities and employers with whom they can work worldwide, this study investigated the teaching of posterior composite restorations in Spanish dental schools. Study design: In late 2009⁄ early 2010, a questionnaire seeking information on the teaching of posterior composites was emailed to the professor responsible for teaching operative dentistry in each of the fifteen dental schools having complete undergraduate dental degree programmes in Spain. Results: The response rate was 100%. Most investigated topics did not show noteworthy differences depending on whether the schools were public or private. Variations were found among Spanish dental schools in both the amount and content of the teaching programmes concerning posterior composite restorations. Differences were recorded in the teaching of cavity design, contraindications to composite placement, indications for liners and bases, matrix and wedging techniques, composite and bonding systems, light curing and finishing procedures for composite restorations. More consistency was observed in teaching methods of moisture-control, indirect composites and amalgam bonding . Conclusions: As recommended in previously surveyed countries, efforts must be made to promote harmonization of dental curricula to make it easier for graduates to work elsewhere, and to ensure they meet the needs of their patients on entering independent practice (AU)

Resistance to bond degradation between dual-cure resin cements and pre-treated sintered CAD-CAM dental ceramics

Objective: To evaluate the bond stability of resin cements when luted to glass-reinforced alumina and zirconia CAD/CAM dental ceramics. Study design: Eighteen glass-infiltrated alumina and eighteen densely sintered zirconia blocks were randomly conditioned as follows: Group 1: No treatment; Group 2: Sandblasting (125 µm Al2O3-particles); and Group 3: Silica-coating (50 µm silica-modified Al2O3-particles). Composite samples were randomly bonded to the pretreated ceramic surfaces using different resin cements: Subgroup 1: Clearfil Esthetic Cement (CEC); Subgroup 2: RelyX Unicem (RXU); and Subgroup 3: Calibra (CAL). After 24 h, bonded specimens were cut into 1 ± 0.1 mm2 sticks. One-half of the beams were tested for microtensile bond strength (MTBS). The remaining one-half was immersed in 10 % NaOCl aqueous solution (NaOClaq) for 5 h before testing. The fracture pattern and morphology of the debonded surfaces were assessed with a field emission gun scanning electron microscope (FEG-SEM). A multiple ANOVA was conducted to analyze the contributions of ceramic composition, surface treatment, resin cement type, and chemical challenging to MTBS. The Tukey test was run for multiple comparisons (p < 0.05). Results: After 24 h, CEC luted to pre-treated zirconia achieved the highest MTBS. Using RXU, alumina and zirconia registered comparable MTBS. CAL failed prematurely, except when luted to sandblasted zirconia. After NaOClaq storage, CEC significantly lowered MTBS when luted to zirconia or alumina. RXU decreased MTBS only when bonded to silica-coated alumina. CAL recorded 100 % of pre-testing failures. Micromorphological alterations were evident after (..) (AU)

Determining efficacy of monitoring devices on ceramic bond to resin composite

Objectives: This paper aims to assess the effectiveness of 3D nanoroughness and 2D microroughness evaluations, by their correlation with contact angle measurements and shear bond strength test, in order to evaluate the effect of two different acids conditioning on the bonding efficacy of a leucite-based glass-ceramic to a composite resin. Study Design: Ceramic (IPS Empress) blocks were treated as follows: 1) no treatment, 2) 37% phosphoric acid (H3PO4), 15 s, 3) 9% hydrofluoric acid (HF), 5 min. Micro- and nano-roughness were assessed with a profilometer and by means of an atomic force microscopy (AFM). Water contact angle (CA) measurements were determined to assess wettability of the ceramic surfaces with the asixymetric drop shape analysis contact diameter technique. Shear bond strength (SBS) was tested to a resin composite (Z100) with three different adhesive systems (Scotchbond Multipurpose Plus, Clearfil New Bond, ProBOND). Scanning electron microscopy (SEM) images were performed. Results: Nanoroughness values assessed in 50x50 ìm areas were higher for the HF group, these differences were not detected by profilometric analysis. HF treatment created the nano- roughest surfaces and the smallest CA (p<0.05), producing the highest SBS to the composite resin with all tested adhesive systems (p<0.05). No differences existed between the SBS produced by the adhesive systems evaluated with any of the surface treatments tested. Conclusions: Nano-roughness obtained in a 50x50 µm scan size areas was the most reliable data to evaluate the topographical changes produced by the different acid treatments on ceramic surfaces (AU)

Effect of aluminum chloride hemostatic agent on microleakage of class V composite resin restorations bonded with all-in-one adhesive

Objectives: Since hemostatic agents can induce changes on enamel and dentin surfaces and influence composite resin adhesion, the aim of the present study was to evaluate the effect of the aluminum chloride hemostatic agent on the gingival margin microleakage of class V (Cl V) composite resin restorations bonded with all-in-one adhesive. Study design: Cl V cavities were prepared on the buccal surfaces of 60 sound bovine permanent incisors. Gingival margins of the cavities were placed 1.5 mm apical to the cemento-enamel junction (CEJ). The teeth were randomly divided into two groups of 30. In group 1, the cavities were restored without the application of a hemostatic agent; in group 2, the cavities were restored after the application of the hemostatic agent. In both groups all-in-one adhesive and Z250 composite resin were used to restore the cavities with the incremental technique. After finishing and polishing, the samples underwent a thermocycling procedure, followed by immersion in 2% basic fuschin solution for 24 hours. The samples were sectioned and gingival microleakage was evaluated under a stereomicroscope. The non-parametric Mann-Whitney U test was used to compare microleakage between the two groups. Statistical significance was defined at P<0.05. Results: A statistically significant difference was observed in microleakage between the two groups (P<0.001). Conclusions: Contamination of Cl V composite resin restorations bonded with all-in-one adhesive with aluminum chloride hemostatic agent significantly increases restoration gingival margin microleakage (AU)

Effect of two prophylaxis methods on adherence of Streptococcus mutans tomicrofilled composite resin and giomer surfaces

Objectives: Surface attributes of a restoration play an important role in adherence of plaque bacteria. Prophylaxismethods may be involved in modification of or damaging the restoration surface. The aim of the present studywas to evaluate the effect of two prophylaxis methods on adherence of Streptococcus mutans to the surface of tworestorative materials. Study design: A total of 60 specimens were prepared from each material; a microfilled compositeresin (HelioProgress) and a giomer (Beautifil II). For each material, the specimens were randomly dividedinto three groups (n=20). Group 1: no prophylaxis treatment (control); Group 2: prophylaxis with pumice andrubber cup; Group 3: prophylaxis with air-powder polishing device (APD). The surfaces of selected specimensfrom each group were evaluated under a scanning electron microscope (SEM), and the surface topography formedby the two prophylaxis methods was determined by atomic force microscopy (AFM). Adherence of Streptococcusmutans to the surface of specimens was determined by the plate counting method following immersion in abacterial innoculum for 4 hours, rinsing and sonication. Data were analyzed by two-way ANOVA and post hocTukey test for multiple comparisons. Statistical significance was set at P<0.05. Results: Bacterial adherence wassignificantly affected by both factors: restorative material type and prophylaxis method (P<0.0005). Mean bacterialadhesion was significantly higher in composite groups compared to corresponding giomer groups. Withineach material, bacterial adherence was significantly lower in the control group compared to prophylaxis groups.Prophylaxis with pumice and rubber cup resulted in a significantly lower bacterial adherence compared to (..) (AU)

The cytotoxicity of resin composites cured with three light curingunits at different curing distances

Objective: The purpose of this study was to compare the effect of light curing distance on the cytotoxicity of fiveresin composites cured with three high-power light curing units.Study design: Seven cylindrical discs of each material (Grandio ®, Voco; Filtek ™ Z250, 3M ESPE; Clearfil ™AP-X, Kuraray Co. Ltd.; Aelite ™ LS, Bisco Inc. and Simile ®, Pentron) were cured. For curing, soft-up mode ofquartz-tungsten-halogen, exponential mode of light emitting diode for 20 s, and ramp-curing mode of plasma arclight curing units for 6 s were used. The curing tip distances were determined as 2 and 9 mm and controlled viathe use of metal rings. After ageing the samples for 24 and 72 hours in Dulbecco’s Modified Eagle Medium/Ham’sF12 (DMEM/F12), cytotoxicity of the extracts to cultured fibroblasts (L 929) was measured by using MTT (tetrazoliumsalt 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay. The degree of cytotoxicity foreach sample was determined according to the reference value represented by the cells in a pure culture medium.Statistical significance was determined using multifactorial analysis of variance.Results: The type of resin composite (p<0.05), light curing unit (p<0.05), curing tip distance (p<0.05) and evaluationperiod factor (p<0.05) had statistically significant cytotoxic effects on L–929 mouse fibroblast cells. However,when the tested materials polymerized at both distances (2 mm and 9 mm) in both evaluation periods (24h and72h), there was no significant difference in the mean CSR% values obtained when the quartz-tungsten-halogen,light emitting diode and plasma arc light curing units were used (p=0.184, F=1.448).Conclusions: The results of this study suggest that the light curing units and resin composites should be harmonizedto one another and the curing distance between the tip of the light curing unit and the restoration surfaceshould be as close as possible in order to achieve maximal biocompatibility (AU)

Planificación endodóncico-restauradora para la rehabilitación funcional y estética de incisivos superiores / Endodontic restorative planning for esthetic and functional rehabilitation of maxillary incisors

En la planificación del tratamiento endodóncico debemos establecer conjuntamente un plan clínico sobre las posibilidades restauradoras. El siguiente caso clínico describe el tratamiento endodóncico y restaurador en dos incisivos superiores ampliamente destruidos por caries. El plan de tratamiento clínico empezó en la terapia periodontal, tratamiento endodóncico y en la reconstrucción coronaria con el empleo de pernos intraconductos de fibra de vidrio. El caso clínico ilustra que la planificación restauradora de un diente endodonciado debe ser realizada a la mayor brevedad posible juntamente con el tratamiento del conducto radicular

In the endodontic planning we should have a clinical plan jointly concerning the restoring possibilities. The case reports the endodontic and restorative treatment in two maxillary incisors with extensive carious lesion. The plan of clinical treatment relapsed in the periodontal therapy, endodontic treatment and for the crown reconstruction with the employment of intraradicular glass fiber post. The clinical case illustrates that the restorative planning of an endodontically treated teeth should be carried out to the endodontic treatment jointly preferable quickly as possible (AU)

Resistencia a la flexión de material restaurador estético fotopomerizable reforzado con fibra de carbono / No disponible

El propósito de esta investigación fue evaluar los efectos ocasionados en diferentes materiales restauradores tales como resinas, cerómeros y ormoceras, agregándoles fibra de carbono, utilizando Luz con Emisión de Diodos para su curado, analizando sus propiedades físicas mediante la máquina universal de fuerza Instron 5567, 90 muestras de 25x2x2 mm³ fueron preparadas bajo la norma ISO4049, formando 6 grupos de 15 muestras, para cada uno de los materiales utilizados: composite, cerómero y ormocera con y sin fibra de carbono, y llevadas al aparato Instron 5567 para medir resistencia flexural y módulo de Young, con una velocidad de cruceta constante de (0.75+-0.25) mm/min. radio de descarga de (50+-16) N/min. Se utilizó el paquete estadístico Zigma Stat y Anova de una vía, para obtener la desviación estándar y análisis de varianza. Para comparar los grupos se utilizo la prueba de Tukey con un nivel de significación estadística establecido en P= <0,01. El composite Z250 fue el que obtuvo mayor resistencia flexural en grupo control (sin fibra), mientras que en el grupo con fibra fue SureFil el de mayor resistencia flexural, y la menor resistencia a la flexión con y sin fibra fue admira de Voco (AU)

The purpose of this research if to evaluate the effects caused on different restoring materials such as resins, ceromers and ormocers, when carbon fiber, glass were added, using light with emission of diodes for its hardening, analyzing their physical properties using the strength universal machine Instron 5567.90 samples of 25x2x2 mm3 were prepared under the norm ISO 4049, forming 6 groups of 15 samples for each one of the materials used: composite, ceromer and ormocer with and without carbon fibers, and afterwards taken to the Instron device 5567 to measure flexural resistance and Young module, with a constant crosshead speed of(0.75+-0.25) mm/min. discharge ratio of (50+-16) N/min. The statistic package Zigma Stat and one-channel Anova were usedin order to obtain the standard deviation and variation analysis. To compare the groups, the Tukey test was used with a level of statistic significance established at P=<0.01. The composite Z250 was the one with the most flexural resistance in the control group (with nofiber), while the group with fiber and with no thermo cycling Sure Filwas the one with the most flexural resistance and the one with the least was Voco. In the group with fiber the one with the most flexural resistance was Z 250 with carbon fiber and the one with the least was Voco with and without carbon fiber (AU)

Cytotoxic effects of TEGDMA on THP-1 cells in vitro

Objective: Resin based dental materials are not stable in the oral environment and may release their componentsinto biological media. These components may include substances such as triethylene glycol dimethacrylate(TEGDMA), which is a major co-monomer of dental resin materials. This release can trigger host immune andinflammatory responses against foreign materials, mediated by monocytes. The aim of this study was to investigatethe possible cytotoxic effects of TEGDMA on human THP-1 monocytes.Material and Methods: THP-1 cells were exposed to various concentrations of TEGDMA (0.5 mM, 1 mM, 2 mM,4 mM, or 8 mM) for 48 hours. An untreated group was used as control. The effects of TEGDMA on cell proliferation,cell viability and apoptosis were analyzed by light microscopy.Results: Cell proliferation was inhibited by 4 mM and 8 Mm TEGDMA. Increasing TEGDMA concentrationscaused a decrease in cell viability. All TEGDMA concentrations used in this study had an apoptotic effect onTHP-1 cells when compared with the control group.Conclusions: The dental monomer TEGDMA had an adverse effect on cell proliferation and exerted an apoptoticand toxic effect on THP-1 cells in a concentration-dependent manner (AU)

No disponible