Depth of cure, mechanical properties and morphology of dual-cure bulk-Fill composites / Profundidad de curado, propiedades mecánicas y morfología de resinas compuestas duales

This study evaluated selected structural and physical properties, such as degree of conversion (DC), Vickers hardness (VHN), and compression strength (CS), of three new dual-cure bulk-fill resin-based composites (RBCs; ACTIVA, HyperFIL, and Fill-Up) and compared them to those of a conventional RBC (Filtek Z250) at three clinically relevant depths. Samples (n=180) were prepared in three depths (2,4, and 6mm). Fourier-transform infrared spectroscopy (FTIR) analysis and VHN and CS tests were performed. The DC value was calculated by considering the relative change in the aliphatic C=C peaks. The fractured surfaces of representative samples were characterized using scanning electron microscopy (SEM). Data were statistically evaluated using two-way analysis of variance and post hoc Bonferroni tests (p<0.05). According to the VHN results, Filtek Z250 showed the highest bottom/top hardness ratio (97.94±1.01) at 2mm thickness and ACTIVA showed the lowest bottom/top hardness ratio (43.48±5.64) at 6mm thickness (p<0.001). According to the FTIR results, the DC decreased with increasing thickness in all materials (p<0.05). Filtek Z250 showed the highest (301±12.4 MPa) and ACTIVA exhibited the lowest (232±17.2 MPa) CS values at 2mm thickness (p<0.05). The lowest CS values were obtained for ACTIVA, and the highest values were obtained for Filtek Z250 for samples with thicknesses of 4 and 6mm, respectively (p<0.05). The structural features of restorative composites, such as the resin chemistry and filler type and content, and the operational parameters (i.e., material thickness and curing conditions) strongly affect crosslinking reactions and thus the DC, VHN, and CS values.

Este estudio evaluó propiedades físicas y estructurales, como el grado de conversión (DC), la dureza Vickers (VHN) y la resistencia a la compresión (CS), de tres nuevos compósitos a base de resina de curado dual tipo bulk (RBC; ACTIVA , HyperFIL y Fill-Up) y los comparó con los de una resina compuesta convencional (Filtek Z250) en tres profundidades clínicamente relevantes. Se prepararon muestras (n=180) en tres profundidades (2,4 y 6mm). Se realizaron análisis de espectroscopia infrarroja por transformada de Fourier (FTIR) y pruebas VHN y CS. El valor de DC se calculó considerando el cambio relativo en los picos alifáticos C=C. Las superficies fracturadas de muestras representativas se caracterizaron mediante microscopía electrónica de barrido (MEB). Los datos se evaluaron estadísticamente mediante análisis de varianza de dos vías y pruebas post hoc de Bonferroni (p<0,05). De acuerdo con los resultados de VHN, Filtek Z250 mostró la relación de dureza inferior/superior más alta (97,94±1,01) con un espesor de 2mm y ACTIVA mostró la relación de dureza inferior/superior más baja (43,48±5,64) con un espesor de 6mm (p<0,001). De acuerdo con los resultados de FTIR, la DC disminuyó al aumentar el espesor en todos los materiales (p<0,05). Filtek Z250 mostró los valores de CS más altos (301±12,4 MPa) y ACTIVA los más bajos (232±17,2 MPa) a 2mm de espesor (p<0,05). Los valores más bajos de CS se obtuvieron para ACTIVA y los valores más altos para Filtek Z250 para muestras con espesores de 4 y 6mm, respectivamente (p<0,05). Las características estructurales de las resinas compuestas de restauración, como la química; además del tipo y contenido del relleno, y los parámetros operativos (es decir, el espesor del material y las condiciones de curado) afectan en gran medida las reacciones de interacción química y, por lo tanto, los valores de DC, VHN y CS.

The effect of Phytosphingosine and bioactive glass-ceramics in preventing dental enamel erosion

Abstract This study evaluated the effect of phytosphingosine (PHS) and bioactive glass-ceramic (Biosilicate) on dental enamel in terms of color alteration (ΔE), microhardness, and surface roughness when submitted to erosive challenge (EC). Sixty specimens of bovine teeth (6×6×2mm) were obtained. Initial color (Easyshade, VITA), KHN (HMV-2, Shimadzu), and Ra (SJ-201P, Mitutoyo) measurements were performed. Specimens were separated into groups according to treatments: PHS, 10% Biosilicate, PHS+10% Biosilicate, and artificial saliva (control) and submitted to EC with Coca-Cola for 2 min. This cycle was repeated 4 times daily/15 days. Between cycles, specimens remained in artificial saliva (2 h/37°C). After daily cycles, they were also stored in artificial saliva at 37ºC. Final color, microhardness, and surface roughness measurements were done. Color and KHN data were analyzed by one-way ANOVA, Tukey's test; and Ra, by 2-way ANOVA, repeated measures, and Tukey's test (p<.05). The highest ΔE occurred in Saliva+EC (p<.05). Groups treated with PHS presented lower color change than Saliva+EC (p<.05). All the groups presented mean values above the 50:50% perceptibility (50:50%PT) and acceptability (50:50%AT) thresholds, except for control that showed mean value above 50:50%PT but below 50:50%AT. Biosilicate+EC showed higher relative microhardness than Saliva+EC (p<.05), but was similar to PHS+EC and PHS+Biosilicate+EC. Final enamel surface roughness increased for all the groups (p<.05), except for the control. The Biosilicate may prevent enamel mineral loss induced by erosion better than saliva. The PHS associated or not to Biosilicate demonstrated better color stability than saliva.

Resumo Este estudo avaliou o efeito da Fitoesfingosina (PHS) e da vitrocerâmica bioativa (Biosilicato) sobre o esmalte dental em termos de alteração de cor (ΔE), microdureza (KHN) e rugosidade superficial, quando submetido a desafio erosivo (DE). Sessenta espécimes de dentes bovinos (6×6×2mm) foram obtidos. Foram realizadas leituras de cor inicial (Easyshade, VITA), microdureza (HMV-2, Shimadzu) e rugosidade superfícial (SJ-201P, Mitutoyo). Os espécimes foram separados em grupos de acordo com os tratamentos: PHS, Biosilicato a 10%, PHS+Biosilicato a 10%, e saliva artificial (controle). Em seguida, foram submetidos a DE com Coca-Cola por 2 min. Esse ciclo foi repetido 4 vezes/dia por 15 dias. Entre os ciclos, as amostras foram mantidas em saliva artificial (2 h/37°C). Após os ciclos diários, os espécimes também foram armazenados em saliva artificial a 37ºC. Foram realizadas leituras finais de cor, microdureza e rugosidade superficial. Os dados de cor e microdureza foram analisados ​​por ANOVA de uma via, teste de Tukey; e dados de rugosidade superficial, por ANOVA de duas vias, teste de Tukey (p<.05). A maior ΔE ocorreu em Saliva+DE (p<.05). Grupos tratados com PHS apresentaram menor alteração de cor do que Saliva+DE (p<.05). Biosilicate+DE demonstrou valores intermediários, similar (p>.05) aos outros grupos, exceto Saliva+DE. Todos os grupos presentaram média acima dos limites 50:50% de perceptibilidade (50:50%LP) e aceitabilidade (50:50%LA) exceto o controle que demonstrou média acima do 50:50%LA mas abaixo do 50:50%LP. Biosilicate+DE mostrou maior microdureza realativa do que Saliva+DE (p<.05), mas similar a PHS+DE e PHS+Biosilicato+DE. A rugosidade de superfície do esmalte aumentou para todos os grupos, exceto para o controle que presentou a menor alteração (p<.05). O Biosilicato apode prevenir perda mineral do esmalte indizido pela erosão melhor que a saliva. O PHS associado ou não ao Biosilicato demonstrou melhor estabilidade de cor que a saliva.

Experimental study on the therapeutic effect of different bleaching methods on white-spot lesions of the enamel using optical coherence tomography / 口腔医学

Objective@#To investigate the efficacy of different bleaching methods on white-spot lesions of the enamel using optical coherence tomography and to evaluate its feasibility for monitoring the therapeutic effects on white-spot lesions. @*Methods@#Forty-eight sound premolars extracted for orthodontic reasons were selected and cut for 4 mm×4 mm×2 mm enamel blocks in buccal surfaces of the crowns. The samples were covered with acid-resistant varnish (except for the buccal surfaces) and immersed in demineralization solution for 18 days to establish the white-spot lesion models of the enamels. Samples were randomly divided into four groups (n=12). Group A was given demineralization only. Specimens in Group B, C and D were treated with 40% hydrogen peroxide, resin infiltration and 40% hydrogen peroxide combined with resin infiltration, respectively. Eight samples in each group were randomly selected. OCT was applied to observe the optical changes of the enamel surface and according to the OCT scanning results, the demineralization depth of enamel samples in each group was calculated. Then, the enamel blocks were embedded in epoxy resins, except the buccal surfaces, and measured for the microhardness values of the enamel surface by a microindentation hardness tester. Four samples in each group were cut longitudinally, and the ultrastructural changes of enamel samples in each group were observed by scanning electron microscope. @* Results@#OCT showed that the light scattering characteristics of enamel surface changed in all groups, and the bright layer was formed, but the thickness of bright layer in Group C and D was significantly lower than that in Group A and B (P<0.05). The microhardness values (kg/mm2) of the samples in Group A-D were (214.99±31.70), (250.66±33.64), (312.42±18.01) and(286.53±26.65), respectively. The microhardness of enamel surfaces in Group C and D was significantly higher than that in Group A and B (P<0.05), and the ultrastructure of enamel surfaces in Group C and D were more flat and dense in SEM observation (P<0.05). @*Conclusion@#The methods of resin infiltration therapy or 40% hydrogen peroxide combined with resin infiltration could effectively improve white-spot lesions of the enamel and the non-invasive OCT can be used as a better evaluation method for the diagnosis and treatment of white-spot lesions of the enamel.

The effect of curing modes and times of Third-Generation led LCU on the mechanical properties of nanocomposites / Efecto del modo y tiempo de fotocurado de la lámpara LCU Led de tercera generación en las propiedades mecánicas de los nanocompuestos

Abstract This study evaluates the effect of curing modes and times on the mechanical properties of nanocomposites. Two nanocomposite resins were investigated: suprananohybrid (Estelite Posterior Quick; EP) and nanohybrid (Solare X; SX). They were polymerized with a light-emitting diode light-curing units (LED LCU, Valo) as follows: standard mode for 20s (ST20), high power mode for 12s (HP12), high power mode for 20s (HP20), extra power mode for 6s (XP6), and extra power mode for 20s (XP20). For Vickers microhardness (HV), disc-shaped specimens were fabricated (n=10). For the three-point bending test, bar-shaped specimens were fabricated (n=10). Flexural strength and resilience modulus were calculated. The fractured surfaces and specimen surfaces of composites were observed using scanning electron microscopy. The data were analyzed with repeated measures ANOVA, two-way variance, and Bonferroni tests (p<0.05). On the top and bottom surfaces of the EP nanocomposite resin, ST20 and HP12 revealed statistically higher HV than with XP6. Moreover, HP20 and XP20 had statistically higher HV than HP12 and XP6. For the SX nanocomposite resin, HP20 had statistically higher HV than HP12. For EP and SX, there were no significant differences in flexural strength and resilience modulus regarding the curing modes and times. Furthermore, SX demonstrated lower mechanical properties than EP. Scanning electron microscopy indicated that both nanocomposites had similar surface appearances. However, with all curing modes and times, SX exhibited layered fractures and more crack formations than EP. Different curing modes and times could influence the microhardness of nanocomposites.

Resumen Este estudio evalúa el efecto del modo y tiempo de fotocurado sobre las propiedades mecánicas de los nanocompuestos. Se investigaron dos resinas nanocompuestas: supra-nanohíbrida (Estelite Posterior Quick; EP) y nanohíbrida (Solare X; SX). Se polimerizaron con unidades de fotopolimerización de diodos emisores de luz (LED LCU, Valo) de la siguiente manera: modo estándar durante 20s (ST20), modo de alta potencia durante 12s (HP12), modo de alta potencia durante 20s (HP20) , modo extra power durante 6s (XP6) y modo extra power durante 20s (XP20). Para la microdureza Vickers (HV), se fabricaron especímenes en forma de disco (n=10). Para el ensayo de flexión de tres puntos, se fabricaron probetas en forma de barra (n=10). Se calcularon la resistencia a la flexión y el módulo de resistencia. Las superficies fracturadas se observaron mediante microscopía electrónica de barrido. Los datos se analizaron con ANOVA varianza de dos vías y pruebas de Bonferroni (p<0,05). En las superficies superior e inferior de la resina nanocompuesta EP, ST20 y HP12 revelaron un HV estadísticamente mayor que con XP6. Además, HP20 y XP20 tenían un HV estadísticamente más alto que HP12 y XP6. Para la resina nanocompuesta SX, HP20 tenía un HV estadísticamente más alto que HP12. Para EP y SX, no hubo diferencias significativas en la resistencia a la flexión y el módulo de resistencia con respecto al modo y tiempo de fotocurado. Además, SX demostró propiedades mecánicas inferiores que EP. La microscopía electrónica de barrido indicó que ambos nanocompuestos son similares en la superficie. Sin embargo, SX exhibió fracturas en capas y más formaciones de grietas que EP. Diferentes modos y tiempos de fotocurado podrían influir en la microdureza de los nanocompuestos.

Influence of Bleaching Agent Containing Bioactive Glass on Color and Microhardness of Bovine Enamel

To try to reduce the deleterious effects of tooth whitening, bioactive materials have been used. Forty enamel/dentin blocks were stained on dark tea and randomly assigned into four groups (n=10): control group (unbleached), HP35 % (35 % hydrogen peroxide), BG45S5 (Bioglass 45S5® incorporated into HP35 %), and BIO (Biosilicate® incorporated into HP35 %). Colorimetric analysis and microhardness evaluation was performed at baseline, 24 hours and 7 days after the final whitening session. Two-way ANOVA for repeated measures and Bonferroni test was used at a significance level of 5 %. All the coordinates (ΔL*, Δa*, Δb*, ΔE00 and WID) showed a difference between the control group and the experimental ones (p0.05), which suggest a color stability over a week. In contrast, after 7 days, the WID showed that control and PH35 % were different than the other groups (p 0.05). The microhardness did not change over time (p>0.05), except for 35 % HP. In conclusion Bioglass 45S5® and Biosilicate® prevented enamel damage without negatively affect the whitening efficacy.

Para intentar reducir los efectos nocivos del aclaramiento dental, se han usado materiales bioactivos. Cuarenta bloques de esmalte/dentina se tiñeron con té oscuro y se asignaron al azar en cuatro grupos (n=10): grupo de control (sin blanquear), HP35% (peróxido de hidrógeno al 35 %), BG45S5 (Bioglass 45S5® incorporado en HP35%) y BIO (Biosilicato® incorporado a HP35%). El análisis colorimétrico y la evaluación de la microdureza se realizaron al inicio del estudio, 24 horas y 7 días después de la última sesión de blanqueamiento. Se utilizó ANOVA de dos vías para medidas repetidas y la prueba de Bonferroni a un nivel de significancia del 5 %. Todas las coordenadas (ΔL*, Δa*, Δb*, ΔE00 y WID) mostraron diferencia entre el grupo control y el experimental (p0.05), lo que sugiere una estabilidad del color durante una semana. En cambio, a los 7 días, el WID mostró que el control y el PH35 % eran diferentes a los demás grupos (p 0.05). La microdureza no cambió con el tiempo (p>0.05), excepto para 35 % HP. En conclusión Bioglass 45S5® y Biosilicate® previnieron el daño del esmalte sin afectar negativamente la eficacia del blanqueamiento.

Influence of F-18 Bioactive Glass Incorporation into Whitening Gel on Properties of Bovine Dental Enamel

ABSTRACT: Bioactive materials have shown positive results in reducing the deleterious effects of tooth whitening. However, their effects on whitening efficacy is still uncertain. Therefore, the aim of this study was to evaluate the effects of F- 18 bioactive glass incorporation into a bleaching gel on color and microhardness of enamel after tooth whitening. Thirty bovine enamel-stained specimens were randomly divided into three groups (n=10) according to the whitening protocol: control group (unbleached), HP35 % (35 % hydrogen peroxide) and F-18 (F-18 bioactive glass incorporated into HP35 %). pH, color change and microhardness analyzes were performed at baseline, 24 hours and 7 days after tooth whitening. Color evaluation showed that experimental groups were different than control group for all coordinates (p 0.05). No differences in enamel microhardness were found among the groups within the same evaluation time (p > 0.118). Regarding the intragroup comparisons, no differences were observed for control and F-18 groups (p > 0.129). It was concluded that F-18 bioactive glass incorporation did not affect the whitening efficacy and the enamel microhardness.

RESUMEN: Los materiales bioactivos han mostrado resultados positivos en la reducción de efectos nocivos del aclaramiento dental. Sin embargo, sus efectos sobre la eficacia del aclaramiento aún son inciertos. Por lo tanto, el objetivo de este estudio fue evaluar los efectos de la incorporación de vidrio bioactivo F-18 en un gel aclarador sobre el color y la microdureza del esmalte después del aclariamiento dental. Treinta especímenes bovinos teñidos con esmalte se dividieron aleatoriamente en tres grupos (n=10) de acuerdo con el protocolo de aclaramiento: grupo control (sin aclaramiento), HP35 % (peróxido de hidrógeno al 35 %) y F-18 (vidrio bioactivo F-18 incorporado en HP35 %). Se realizaron análisis de pH, cambio de color y microdureza al inicio del estudio, 24 horas y 7 días después del aclaramiento dental. La evaluación del color mostró que los grupos experimentales eran diferentes al grupo de control en todas las coordenadas (p 0,05). No se encontraron diferencias en la microdureza del esmalte entre los grupos dentro del mismo periodo de evaluación (p > 0,118). En cuanto a las comparaciones intragrupos, no se observaron diferencias para los grupos control y F-18 (p > 0,129). Se concluyó que la incorporación de vidrio bioactivo F-18 no afectó la eficacia de aclaramiento ni la microdureza del esmalte.

Whitening efficacy of popular natural products on dental enamel

Abstract The objective of this study was to evaluate the effect of natural bleaching products on the color, whiteness, and superficial properties of dental enamel. Seventy fragments of bovine teeth were obtained (6mm x 6mm x 2mm). Initial surface roughness (Surfcorder SE1700, Kosakalab), microhardness (HMV-2, Shimadzu), color (EasyShade, VITA), and surface gloss (Micro-Gloss 45º BYK, Gardner) readings were done. Samples were separated into five groups (n=14) according to the treatments used: CT-conventional toothpaste (negative control); CH-charcoal; TU-turmeric; BP-banana peel, and CP16%-16% carbamide peroxide gel (positive control, 4 h/day for 14 days), and then brushed for 560 cycles (T1) and 1200 cycles (T2), equivalent to 14 and 30 days of brushing. New measurements were performed after T1 and T2. The whiteness index for dentistry change (∆WID) and Weight loss (Wl) were calculated. CP16% demonstrated the highest (p<.05) color change (ΔE00) and ∆WID (2-way ANOVA, Bonferroni, p<.05). Surface gloss alterations were lower for TU, CP16%, and BP. CT and CH increased surface roughness (p<.05). CP16% decreased enamel microhardness. CH presented medium abrasiveness, and CT and TU, low abrasiveness. The popular bleaching products were not efficient for tooth whitening. Furthermore, brushing with charcoal increased the enamel surface roughness, and CP16% decreased enamel microhardness over time

Resumo O objetivo deste estudo foi avaliar o efeito de produtos clareadores naturais na cor, efeito clareador e propriedades superficiais do esmalte dentário. Setenta fragmentos de dente bovino foram obtidos (6mm x 6mm x 2mm). Foram realizadas leituras iniciais de rugosidade de superfície (Surfcorder SE1700, Kosakalab), microdureza (HMV-2, Shimadzu), cor (EasyShade, VITA) e brilho (Micro-Gloss 45º BYK, Gardner). As amostras foram separadas em cinco grupos (n=14), de acordo com os tratamentos utilizados: DC - dentifrício convencional (controle negativo); CA - carvão ativado; CM - cúrcuma; CB - casca de banana e PC16% - gel de peróxido de carbamida a 16% (controle positivo, 4h/dia por 14 dias), foram então escovadas por 560 ciclos (T1) e 1200 ciclos (T2), equivalente a 14 e 30 dias de escovação. Novas leituras foram realizadas após T1 e T2. A alteração do whiteness index for dentistry (∆WID) e perda de massa (Pm) foram calculadas. PC16% demonstrou a maior (p<0,05) alteração de cor (ΔE00) e ∆WID (2-way ANOVA, Bonferroni, p<0,05). A alteração de brilho foi menor para CM, PC16% e CB. DC e CA aumentaram a rugosidade de superfície (p<0,05). PC16% diminuiu a microdureza do esmalte. CA apresentou abrasividade média, e DC e CM, baixa abrasividade. Os produtos clareadores populares não foram eficientes para clareamento dental. Ademais, a escovação com carvão ativado aumentou a rugosidade de superfície do esmalte dentário, e com maior tempo PC16% diminuiu a microdureza do esmalte.

How a 16% Carbamide peroxide home Bleaching agent affects the surface properties of chairside CAD/CAM materials? / ¿Cómo afecta un agente blanqueador casero de peróxido de carbamida al 16% a las propiedades de la superficie de los materiales CAD/CAM de consultorio?

Abstract Surface changes of restorative materials after bleaching have clinical importance in terms of the durability and survival of restorations. This study aimed to evaluate the effect of home bleaching on the surface roughness, microhardness, and surface analysis of four different types of chairside computer-aided design and computer-aided manufacturing (CAD/CAM) materials. Specimens were prepared from composite resin (Brilliant Crios: BC), resin nanoceramic (Lava Ultimate: LU), polymerinfiltrated ceramic-network (Vita Enamic: VE), and zirconia-reinforced lithium silicate glass-ceramic (Vita Suprinity: VS) CAD/CAM materials. Specimens were polished using 800, 1000, 1200, and 2000 grit SiC papers. Each restorative material was randomly divided into two groups; control and bleaching (n=10). The 16% carbamide peroxide bleaching agent (Whiteness Perfect 16%, FGM) was applied to the specimens for 4 h/ day for 14 days. Surface roughness values (Ra) were obtained using a profilometer, and microhardness values (VHN) were obtained using a Vickers microhardness test. Surface analysis of specimens was evaluated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Data were analyzed Two-way ANOVA and Fishers Least Significant Difference (LSD) test (p<0.05). After bleaching, the surface roughness of BC (p<0.001) and VE (p<0.032) significantly increased. Bleaching did not significantly affect the microhardness of CAD/CAM materials. SEM evaluation showed material-dependent surface damages after bleaching procedures. The effect of 16% carbamide peroxide home bleaching agent on surface roughness and microhardness of chairside CAD/CAM materials is material-dependent. Before bleaching, restorative materials should be protected by applying a protective barrier and contact with the bleaching agent should be minimized. Also, after bleaching, the restoration surface should be carefully inspected, and re-polishing might be beneficial.

Resumen Los cambios en la superficie de los materiales de restauración tras el blanqueamiento tienen importancia clínica en cuanto a la durabilidad y supervivencia de las restauraciones. Este estudio tenía como objetivo evaluar el efecto del blanqueamiento en casa sobre la rugosidad de la superficie, la microdureza y el análisis de la superficie de cuatro tipos diferentes de materiales de diseño asistido por computadora y fabricación asistida por computadora (CAD/CAM). Se prepararon especímenes de materiales CAD/CAM de resina compuesta (Brilliant Crios: BC), de nanocerámica de resina (Lava Ultimate: LU), de cerámica en red infiltrada por polímeros (Vita Enamic: VE) y de cerámica de vidrio de silicato de litio reforzada con circonio (Vita Suprinity: VS). Las muestras se pulieron con papeles de SiC de grano 800, 1000, 1200 y 2000. Cada material de restauración se dividió aleatoriamente en dos grupos: control y blanqueo (n=10). El agente blanqueador de peróxido de carbamida al 16% (Whiteness Perfect 16%, FGM) se aplicó a las muestras durante 4 h/día durante 14 días. Los valores de rugosidad de la superficie (Ra) se obtuvieron utilizando un perfilómetro, y los valores de microdureza (VHN) se obtuvieron utilizando una prueba de microdureza Vickers. El análisis de la superficie de las muestras se evaluó mediante microscopía electrónica de barrido (SEM) y espectroscopia de rayos X de energía dispersiva (EDX). Los datos se analizaron mediante ANOVA de dos vías y la prueba de diferencia mínima significativa (LSD) de Fisher (p<0,05). Tras el blanqueamiento, la rugosidad de la superficie del CB (p<0,001) y del VE (p<0,032) aumentó significativamente. El blanqueamiento no afectó significativamente a la microdureza de los materiales CAD/CAM. La evaluación SEM mostró daños superficiales dependientes del material después de los procedimientos de blanqueo. El efecto del agente blanqueador casero de peróxido de carbamida al 16% sobre la rugosidad de la superficie y la microdureza de los materiales CAD/CAM en el sillón depende del material. Antes del blanqueamiento, los materiales de restauración deben protegerse aplicando una barrera protectora y debe minimizarse el contacto con el agente blanqueador. Además, después del blanqueamiento, la superficie de la restauración debe inspeccionarse cuidadosamente y puede ser beneficioso volver a pulirla.

Comparative evaluation of chelating efficacy of nano-chitosan, pomegranate extract, and ethylenediaminetetraacetic acid on primary radicular dentin An in vitro study

Background: Irrigation is a crucial aspect of root canal treatment, and it is imperative to employ chelating agents to eliminate the smear layer during biomechanical preparation. They in turn react with mineral content of dentin, leading to decreased strength and increased susceptibility to fracture. Aims: This study aimed to assess and compare mineral loss and microhardness from primary root canal dentin following the usage of different irrigating solutions and determine the least detrimental irrigant among the tested solutions. Materials and Methods: Sixty-six primary anterior teeth were divided into three groups with 22 in each– Group I: 17% ethylenediaminetetraacetic acid (EDTA) Group II: 0.2% Nano chitosan Group III: Pomegranate extract. The decoronated teeth were split longitudinally. Half of it was directly subjected to Vickers test, and the other half was immersed in a magnetic stirrer bath containing test solution to record the mineral loss from solution. Postmicrohardness values were recorded on the specimen and compared with initial values. Statistical Analysis Used: Statistical analysis was done using SPSS software (Version 20, SPSS, IBM, Armonk, NY, U. S. A). Results: Descriptive statistics were calculated, and the groups were compared using analysis of variance test and post hoc Tukey test. Pomegranate extract showed least effect on mineral content and microhardness compared to 17% EDTA and 0.2% nano chitosan. P ≤ 0.05 was considered statistically significant. Conclusion: Pomegranate aril extract showed better results with selected parameters.

Pre-Heating effect on the microhardness and depth of cure of Bulk-Fill composite resins / Efecto del precalentamiento de las resinas compuestas Bulk-Fill en la microdureza y la profundidad de curado

Abstract The aim of this study was to investigate the effect of preheating three bulk-fill and one conventional composite resin on the Vickers microhardness and depth of cure of these composites. In this study, three bulk-fill composites- SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), and one conventional composite resin G-ænial POSTERIOR (GP) were used as the control group. The samples were obtained at room temperature (24°C) and at 55°C in T2 mode after being placed in a heating device for 10 minutes. The samples were divided into eight groups (n=10) according to the type of material and heating process that was utilized (preheated and nonheated). All samples were tested with a Vickers microhardness (VHN) tester on the bottom and top surfaces. The first measurements were obtained at baseline; the second set of measurements was performed after the samples were stored in distilled water at 37°C for 24 hours. The depth of cure was calculated using a bottom/top hardness ratio of measurements. Statistical analysis was performed utilizing the SPSS V23 and Shapiro-Wilk tests. Lastly, the Duncan test was used for multiple comparisons (p<0.05). While the VHN increased after the preheating procedure in bulk-fill composites, it decreased in GP. There was no difference between the baseline and the 24-hour VHN values in SDR and GP. After 24 hours, while the VHN of EST increased, the VHN of AFX decreased. There was no difference between the hardness ratios of the AFX and EST samples (p<0.001) and hardness ratios were greater than GP and SDR. When comparing the baseline and the 24- hour values, the VHN depended on the type of materials. Sufficient curing depth was obtained in all groups with a thickness of 2mm.

Resumen El objetivo fue investigar el efecto del precalentamiento de tres resinas Bulk-fill, una resina compuesta convencional sobre la microdureza Vickers y la profundidad de curado de estas resinas. Se utilizaron tres composites Bulk-Fill-SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), y una resina compuesta convencional G-ænial POSTERIOR (GP) como grupo de control. Las muestras se obtuvieron a temperatura ambiente (24°C) y a 55°C en modo T2 después de haber sido colocadas en un dispositivo de calentamiento durante 10 minutos. Se dividieron en ocho grupos (n=10) según el tipo de material y el proceso de calentamiento que se utilizó (precalentado y no calentado). Se probaron con un medidor de microdureza Vickers (VHN) en las superficies inferior y superior. Las primeras mediciones se obtuvieron en la línea de base; la segunda se realizó después de que las muestras se almacenaran en agua destilada a 37°C durante 24 horas. La profundidad de curado se calculó utilizando una relación de dureza inferior/ superior de las mediciones. El análisis estadístico se realizó utilizando el SPSS V23 y las pruebas de Shapiro-Wilk. Por último, se utilizó la prueba de Duncan para las comparaciones múltiples (p<0,05). VHN aumentó tras el procedimiento de precalentamiento en las resina Bulk-Fill, disminuyó en los GP. No hubo diferencias entre los valores de VHN de referencia y de 24 horas en SDR y GP. Después de 24 horas, mientras que el VHN de EST aumentó, el VHN de AFX disminuyó. No hubo diferencias entre los ratios de dureza de las muestras de AFX y EST (p<0,001) y los ratios de dureza fueron mayores que los de GP y SDR. Al comparar los valores de referencia y los de 24 horas, el VHN dependió del tipo de materiales. Se obtuvo una profundidad de curado suficiente en todos los grupos con un grosor de 2mm.

Effect of resin infiltration and bleaching on surface roughness and microhardness of human enamel with induced white spot lesions / Efeito do infiltrante resinoso e do clareamento na rugosidade e microdureza de superfície do esmalte humano com lesões de mancha branca induzidas

Objective: To comparatively evaluate the effect of resin infiltration, bleaching and bleaching followed by resin infiltration on the surface roughness and microhardness of human enamel with induced white spot lesions (WSLs) and their resistance to acidic challenge. Material and Methods: Sixty human specimens were randomly divided into three groups (n=20) according to the treatment modality applied; group I Icon® resin infiltration, group II bleaching and group III bleaching followed by Icon® resin infiltration. For each treatment modality, 10 specimens were tested for surface roughness and another 10 for microhardness. WSLs were artificially induced in all specimens and after treatment, all specimens were subjected to acidic challenge. Surface roughness was measured by the tapping mode of the atomic force microscope (AFM) and microhardness was measured by digital Vickers hardness tester at baseline, after induction of WSLs, after treatment and after acidic challenge. Results: Groups I and III showed significant reduction in surface roughness after treatment, while group II showed significant increase. Groups I and III showed significant increase in the microhardness after treatment, while group II showed insignificant increase. The three tested groups showed significant increase in surface roughness values and significant reduction in microhardness after acidic challenge. Conclusion: Resin infiltration and bleaching followed by resin infiltration reduced the surface roughness and enhanced the microhardness of the WSLs. The three treatment modalities failed to resist acidic challenge resulting in increasing surface roughness and reducing microhardness. (AU)

Objetivo: Avaliar comparativamente o efeito do infiltrante resinoso, clareamento e clareamento seguido de infiltração resinosa sobre a rugosidade e microdureza superficial do esmalte humano com lesões de manchas brancas induzidas (WSLs) e sua resistência ao desafio erosivo. Material e Métodos: Sessenta espécimes humanos foram divididos aleatoriamente em três grupos (n = 20) de acordo com a modalidade de tratamento aplicada; grupo I infiltrante resinoso Icon®, grupo II clareamento e grupo III clareamento seguido de infiltração resinosa Icon®. Para cada modalidade de tratamento, 10 corpos-de-prova foram testados para rugosidade superficial e outros 10 para microdureza. WSLs foram artificialmente induzidos em todas as amostras e, após o tratamento, todas as amostras foram submetidas ao desafio erosivo. A rugosidade de superfície foi medida por microscopia de força atômica em modo de contato intermitente (AFM) e a microdureza Vickers foi medida inicialmente, após a indução de WSLs, após o tratamento e após o desafio ácido. Resultados: Os grupos I e III apresentaram redução significativa da rugosidade superficial após o tratamento, enquanto o grupo II apresentou aumento significativo. Os grupos I e III apresentaram aumento significativo na microdureza após o tratamento, enquanto o grupo II apresentou aumento insignificante. Os três grupos testados mostraram aumento significativo nos valores de rugosidade superficial e redução significativa na microdureza após o desafio erosivo. Conclusão: O infiltrante resinoso e o clareamento seguido de infiltração resinosa reduziram a rugosidade de superfície e aumentaram a microdureza dos WSLs. As três modalidades de tratamento falharam em resistir ao desafio erosivo, resultando em aumento da rugosidade de superfície e redução da microdureza.(AU)

Efecto de la exposición a bebidas carbonatadas en la dureza superficial de resinas acrílicas / Effect of Exposure to Carbonated Beverages on the Surface Hardness of Acrylic Resins

ABSTRACT: The purpose of this study was to evaluate and compare the effect of carbonated beverage on the surface microhardness of two acrylic materials used to fabricate temporary restorations. The study was experimental in vitro. Forty blocks of acrylic resins used in provisional restorations were made, 20 from Alike® (GC AMERICA INC., Lot 1712161) and 20 from Acryptemp® (Zhermack S.P.A., Lot 302334). After that, the blocks were immersed in distilled water for 24 hours. After this time, the initial surface microhardness was measured. Then the 20 samples of the experimental group were immersed in a carbonated drink (coca cola - soda) for 12 minutes per day, for 5 days. Finally, the final surface microhardness was measured using the Vickers microdurometer. Measures of central tendency and dispersion were used, and the Student's t test and ANOVA were performed. A mean surface microhardness of 8.8 and 7.2HV was found for the PMMA resin group (Initial and final respectively), and 9.5 and 8HV for the bisacrylate group. Statistically significant differences were found when comparing the beginning and end of each group and when comparing the two materials. The acrylic resin of polymethylmethacrylate (Alike® GC AMERICA INC.) Presented higher surface microhardness compared to the bis acrylic resin (Acrytemp® Zhermack S.P.A), after being exposed to a carbonated drink.

RESUMEN: El propósito de este estudio fue evaluar y comparar el efecto de la bebida carbonatada en la microdureza superficial de dos materiales acrílicos utilizados para confeccionar restauraciones provisionales. El estudio fue experimental in vitro. Se confeccionaron 40 bloques de resinas acrílicas utilizadas en provisorios, 20 de Alike® (GC AMERICA INC., Lote 1712161) y 20 de Acryptemp® (Zhermack S.P.A., Lote 302334). Posterior a ello, se sumergió los bloques en agua destilada por 24 horas. Pasado este tiempo se procedió a medir la microdureza superficial inicial. Luego las 20 muestras del grupo experimental se sumergieron en una bebida carbonatada (coca cola-gaseosa) durante 12 minutos por día, durante 5 días. Por último se midió la microdureza superficial final mediante el microdurómetro de Vickers. Se utilizaron medidas de tendencia central, dispersión y se realizaron la prueba t de Student y ANOVA. Se encontró una microdureza superficial media de 8,8 y 7,2HV para el grupo de resina PMMA (Inicial y final respectivamente), y 9,5 y 8HV para el grupo de bisacrilato. Se halló diferencias estadísticamente significativas al comparar el inicio y final de cada grupo y al comparar los dos materiales. La resina acrílica de polimetilmetacrilato (Alike® GC AMERICA INC.) presentó mayor microdureza superficial en comparación con la resina bis acrílica (Acrytemp® Zhermack S.P.A), después de ser expuestas a una bebida carbonatada.

Effect of Surface Wetting Resin on the Color Stability and Microhardness of Esthetic Composites / Efecto de la resina humectante de superficies sobre la estabilidad del color y la microdureza de resinas compuestas estéticas

ABSTRACT: Objective: The aim of this study was to evaluate and compare the effects of the superficial application of two different modeling resins on the surface microhardness and discoloration of composite resins. Material and Methods: The present study used two different composites and modeling resins. The composites were placed in plastic molds. Subsequently, the modeling resins were applied on the surface of the two composite groups. The microhardness and color pertaining to all the groups were evaluated. The current study used the One-Way ANOVA and Kruskal Wallis tests, in order to perform the statistical evaluation (p<0.05). Results: The present study compared the microhardness pertaining to the groups and the highest microhardness values were observed in the Estelite Asteria group (none), whereas the lowest values were observed in the GC Essentia group (Ultradent). Moreover, the current study evaluated the color stability and the greatest discoloration was observed in the control group of the GC Essentia group, whereas the least discoloration was observed in the Estelite Asteria group that included the samples prepared using Ultradent Wetting Resin. Conclusions: The results of the present study demonstrated that the use of modeling resins, which facilitate the placement of composite resins, reduced the microhardness and discoloration of composite resins. The aforementioned effect can be attributed to the variations in the structure of the filling. However, further studies are warranted to support and verify the results of the current study.

RESUMEN: Objetivo: El objetivo del presente estudio fue evaluar y comparar los efectos de la aplicación superficial de dos resinas humectantes sobre la microdureza superficial y la decoloración de las resinas compuestas. Material y métodos: El presente estudio utilizó dos resinas humectantes y resinas de modelado diferentes. Las resinas compuestas se colocaron en moldes de plástico. Posteriormente, se aplicaron las resinas humectantes sobre la superficie de los dos grupos. Se evaluó la microdureza y el color de todos los grupos. El presente estudio utilizó las pruebas One-Way ANOVA y Kruskal Wallis, para realizar la evaluación estadística (p<0.05). Resultados: Los valores más altos de microdureza se observaron en el grupo Estelite Asteria, mientras que los menores valores se observaron en el grupo GC Essentia (Ultradent). La mayor decoloración se observó en el grupo control o el grupo GC Essentia, mientras que la menor decoloración se observó en el grupo Estelite Asteria con Ultradent Wetting Resin. Conclusiones: Los resultados del presente estudio demostraron que el uso de resinas humectantes, que facilitan la colocación de resinas compuestas, redujo la microdureza y decoloración de las resinas compuestas. El efecto mencionado anteriormente se puede atribuir a las variaciones en la estructura del relleno. Sin embargo, se necesitan más estudios para respaldar y verificar los resultados del presente estudio.

Microdureza de dos materiales endodónticos a base de silicato de calcio. Un ensayo ex vivo / Surface microhardness of two calcium silicate-based endodontic materials. An ex vivo assay

esumen Objetivo: Comparar la microdureza de dos materiales endodónticos a base de silicato de calcio: MTA Densell Endo Sealer y TotalFill BC Sealer. Materiales y métodos: Se evaluó la microdureza de los selladores MTA Densell Endo Sealer (Grupo 1, n=5) y To- talFill BC Sealer (Grupo 2, n=5) contenidos en cilindros de dentina de vacuno a los 14 días posteriores a su fraguado. La medición se realizó a temperatura ambiente mediante la prue- ba de indentación Vickers. Se realizaron cinco indentaciones por probeta con una carga de 100 g durante 10 s cada una. Las mediciones se convirtieron a valores de dureza Vickers (HV) y los promedios de los valores HV de cada grupo se compararon por medio de la prueba t de Student con un nivel de significación de P <0,05. Resultados: A los 14 días, luego del fraguado, la mi- crodureza de MTA Densell Endo Sealer fue significativamen- te mayor (P=0,001) que la de TotalFill BC Sealer. Conclusiones: Los resultados sugieren que a causa de su dureza la remoción de MTA Densell Endo Sealer puede resultar dificultosa cuando está indicado un retratamiento (AU)

Aim: To compare the microhardness of two silicate-based endodontic materials: MTA Densell Endo Sealer and Total Fill BC Sealer. Materials and methods: Samples of MTA Densell Endo Sealer (Group 1, n=5) and Total Fill BC Sealer (Group 2, n=5) contained into cow dentine cylinders were subjected to the Vickers Microhardness Indentation test at room temper- ature and 14 days after setting. Five indentations per sample were performed under a load of 100 g for 10 s. The indenta- tion measurements were converted into hardness values (HV). Mean HV values of each group were compared using the Stu- dent t test at a significance level of P <0,05. Results: 14 days after setting, the microhardness of MTA Densell Endo Sealer was significantly greater (P=0,001) than that of Total Fill BC Sealer. Conclusions: The results of this study suggest that due to its hardness the removal of MTA Densell Endo Sealer could be difficult to perform when a root canal retreatment is indicated (AU)

Expiration Date Effect on Mechanical and Chemical Properties of Glass Ionomer Cements

ABSTRACT: The glass ionomer cements (GICs) is a generic name given to a group of materials widely used in clinical dentistry which if used after the specified expiration date, material properties may be affected. to evaluate the Vick ers microhardness, surface morphology and the energy dispersive X-ray microanalysis (EDX), of GICs with different expiration dates that were stored at room temperature. specimens of highly viscous glass ionomer cement (HVGIC) (Ketac Cem and Ketac Molar) and resin-modified glass ionomer cement (RMGIC) (Vitrebond) with different expiration dates (current, close to their expiration and expired) were prepared for Vickers microhardness test and scanning electronic microscopy (SEM) with EDX, measuring 5 mm in diameter and 2 mm length, per the manufacturer's instructions, in standard cylindrical teflon molds. For the comparison of obtained values, the ANOVA test was used, while Tukey test was used for the multiple comparisons. In all the GICs used, the microhardness decreased as the expiration date approached, finding a significant statistical differen ce (P<0.05) in Ketac Molar and Vitrebond. SEM sample analysis revealed similar cohesive cracks in all tested materials. The EDX analysis revealed the presence of the elements F, Al and Si in all GICs and Ca only in Ketac Molar and Ketac Cem. The elements were found in a higher atomic percentage in the GICs with an current date and in a lower percentage in those with an expired date. HVGIC and RMGIC with an expiration date finish and that were stored at room temperature, suffer significant physical and chemical changes, which could put doubts its clinical effectiveness.

RESUMEN: El cemento de ionómero de vidrio (CIV) es un nombre genérico que se le da a un grupo de materiales ampliamente utilizados en odontología clínica que si se usan después de la fecha de vencimiento especificada, las propiedades del material pueden verse afectadas. evaluar la microdureza Vickers, la morfología superficial y el microanálisis de energía dispersa de rayos X (EDX), de CIV con diferentes fechas de caducidad almacenados a temperatura ambiente. Muestras de cemento de ionómero de vidrio de alta viscosidad (CIVAV) (Ketac Cem y Ketac Molar) y cemento de ionómero de vidrio modificado con resina (CIVMR) (Vitrebond) con diferentes fechas de vencimiento (vigente, próximo a su vencimiento y vencido) de 5 x 2 mm, fueron preparadas para microscopía electrónica de barrido (MEB) con EDX y microdureza Vickers, según las instrucciones del fabricante, en moldes de teflón cilíndricos estándar. Para la comparación de los valores obtenidos se utilizó la prueba ANOVA, mientras que para las comparaciones múltiples se utilizó la prueba de Tukey. En todos los CIV utilizados, la microdureza disminuyó a medida que se acercaba la fecha de vencimiento, encontrándose una diferencia estadística significativa (P <0.05) en Ketac Molar y Vitrebond. El análisis de la muestra en MEB reveló grietas cohesivas similares en todos los materiales probados. El análisis EDX reveló la presencia de los elementos F, Al y Si en todos los GIC y Ca solo en Ketac Molar y Ketac Cem. Los elementos se encontraron en mayor porcentaje atómico en los GIC con fecha vigente y en menor porcentaje en aquellos con una fecha vencida. Los CIVAV y CIVMR con fecha de caducidad vencida y que fueron alma- cenados a temperatura ambiente, sufrieron cambios físicos y químicos importantes, lo que podría poner en duda su efectividad clínica.

Análisis Elemental de las Propiedades Morfológicas, Físicas y Químicas de Dos Instrumentos Rotatorios Protaper Universal

RESUMEN: Los instrumentos rotatorios utilizados en el tratamiento de conductos dentales necesitan cumplir con ciertas características físicas que le confieran un uso correcto, adecuado y seguro para su uso clínico. En el mercado comercial existen una serie de instrumentos importados que dejan en duda la autenticidad de estos debido a sus bajos costos. En este estudio evaluamos física, química y morfológicamente dos kits de instrumentos rotatorios Protaper universal (Dentsply) mediante análisis de MEB, EDX, microdureza y EDS. Uno de los kits (grupo 1) se adquirió directamente de la casa comercial y otro kit importado que a simple vista no parecía cumplir con los estándares de calidad de un correcto empaquetado (grupo 2). En el análisis de MEB se observaron características morfológicas muy diferentes entre ambos kits, el grupo 2 presentó diversas irregularidades en la superficie de las limas, sin embargo, en el EDS no se encontró diferencia alguna. En cuanto al análisis de microdureza se observó una estadística estadísticamente significativa y en el EDS se observaron mayores picos de intensidad en cuanto a la aleación de Ni-Ti en el grupo 2. Estos resultados sugieren que existen instrumentos rotatorios importados que a pesar de su bajo costo pueden presentar ciertas características muy similares a los kits auténticos, sin embargo, física y químicamente pueden resultar en un riesgo para su uso clínico debido a la diferencia entre estos.

ABSTRACT: Rotatory files are instruments used in the treatment of dental canals roots. These instruments need to comply with certain physical characteristics for a correct, adequate and safe use for clinical use. In the commercial market there are a series of imported instruments that cast doubt on their authenticity due to their low costs. In this study we physically, chemically and morphologically evaluated two Protaper universal rotary instrument kits (Dentsply) using SEM, EDX, microhardness and EDS analysis. One of the kits (group 1) was purchased directly from the commercial house and another imported kit that a simple view did not seem to meet the quality standards of a correct packaging (group 2). In the SEM analysis, very different morphological characteristics were observed between both kits, group 2 presented various irregularities on the surface of the files, however, no difference was found in the EDS. Regarding the microhardness analysis, a statistically significant statistic was observed and in the EDS, higher intensity peaks were observed in terms of the Ni-Ti alloy in group 2. These results suggest that there are imported rotary instruments that despite their low cost can present characteristics very similar to authentic kits, however, physically and chemically they can result in a risk for their clinical use due to the difference between them.

Microhardness homogeneity of RBCs light-cured with a multiple-peak LED and surface characterization after wear

Abstract This in vitro study evaluated the effect of the beam homogeneity of a multiple-peak light-curing unit on the surface microhardness and the effect of toothbrushing wear on the microhardness, surface roughness, roughness profile, volume loss, and gloss retention of incremental and bulk-fill resin-based composites (RBCs). A LED light-curing unit (VALO) with four LEDs at the tip end (405, 445, 465A, and 465B nm emission peak) was used according to each manufacturer-recommended time to obtain disks (n=10) of six RBCs: Estelite Sigma Quick, Charisma Classic, Tetric EvoCeram Bulk Fill, Filtek Z250, Filtek Supreme Ultra, and Filtek Bulk Fill. Microhardness values were obtained according to each LED positioning of the light-curing unit on the top surface of the RBCs and were analyzed before and after toothbrushing regarding microhardness, surface roughness, roughness profile, volume loss, and gloss retention. Microhardness was considered homogeneous on the top surface regardless of the type of RBC or wavelength tested (p>0.05). Overall, toothbrushing did not reduce the microhardness of the RBCs but influenced the gloss values for most RBCs (p<0.001). Charisma Classic presented the greatest surface roughness and roughness profile after toothbrushing (p<0.05). Volume loss did not differ among RBCs (p>0.05). In conclusion, different wavelengths of the LED did not affect the top surface microhardness, regardless of the RBCs tested; and bulk-fill composites presented similar surface changes (microhardness, surface roughness, roughness profile, volume loss, and gloss retention) when compared to conventional composites after toothbrushing.

Resumo Este estudo in vitro avaliou a homogeneidade do feixe de um fotopolimerizador de múltiplos picos na microdureza superficial e o efeito da escovação na microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e retenção do brilho de compósitos a base de resina (RBCs) incrementais ou bulk-fill. Um fotopolimerizador LED (VALO) com quatro LEDs na ponteira (405, 445, 465A e 465B nm de pico de emissão) foi usado de acordo com o tempo recomendado por cada fabricante para obtenção de discos (n=10) de seis RBCs: Estelite Sigma Quick, Charisma Classic, Tetric EvoCeram Bulk Fill, Filtek Z250, Filtek Supreme Ultra e Filtek Bulk Fill. Os valores de microdureza foram obtidos seguindo o posicionamento de cada LED na superfície superior das amostras e foram analisados antes e após a escovação quanto a microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e retenção do brilho. A microdureza foi considerada homogênea no topo da superfície, independentemente do tipo de RBCs ou comprimento de onda testados (p>0.05). No geral, a escovação não reduziu a microdureza das RBCs, mas influenciou o brilho para a maioria das RBCs (p<0.001). Charisma Classic apresentou os maiores valores de rugosidade superficial e perfil de rugosidade após a escovação (p<0.05). A perda de volume não diferiu entre as RBCs (p>0.05). Em conclusão, os diferentes comprimentos de onda do LED não alteraram a microdureza do topo da superfície, independentemente das RBCs testadas; e as resinas bulk-fill apresentaram alterações superficiais similares (microdureza, rugosidade superficial, perfil de rugosidade, perda de volume e manutenção do brilho) quando comparadas às resinas convencionais após a escovação.

Influência de substâncias irrigadoras endodônticas na microdureza da dentina radicular: revisão integrativa / Influence of endodontic irrigation substances on the microdurity of the radicular dentin: integrative review

As soluções de irrigação são essenciais como auxiliares na limpeza e desinfecção do sistema de canais radiculares (SCR). Entretanto, essas substâncias químicas podem gerar alterações na composição da dentina. Assim, o presente estudo teve como objetivo avaliar, por meio de uma revisão integrativa, os efeitos do hipoclorito de sódio (NaOCl) a 1%; 2,5%; 3%; 5%; 5,25%; 6% e 17%; digluconato de clorexidina (CHX) a 2% e EDTA 2,5%; 5%; 15% e 17% sobre a microdureza da dentina do canal radicular após sua utilização como solução irrigadora. Foi realizada uma revisão integrativa nas bases de dados: PubMed, Cochrane e Lilacs, utilizando-se os seguintes descritores em inglês: "irrigating solutions"; "chelaling agentes"; "dentin microhardness"; "EDTA"; "sodium hypochlorite"; "chlorhexidine gluconate". Foi utilizado o conector "and" associando dentin microhardness aos outros descritores. Critérios de inclusão: Artigos científicos na área da odontologia, escritos em inglês e português que aborda o tema "As soluções de hipoclorito de sódio (NaOCl), digluconato de clorexidina (CHX) e EDTA influenciam na microdureza da dentina radicular?''. Critérios de exclusão: artigos repetidos em mais de uma base de dados, livros, teses de doutorado, dissertações de mestrado, resumos e trabalhos publicados em congresso. Fortes evidências indicam que o hipoclorito de sódio, digluconato de clorexidina e EDTA influenciam na microdureza da dentina radicular, quando utilizadas como solução irrigadora durante o tratamento endodôntico... (AU)

Irrigation solutions are essential as an aid in cleaning and disinfecting the root canal system (SCR). However, these chemicals can cause changes in the composition of dentin. Thus, the present study aimed to evaluate, through an integrative review, the effects of 1% sodium hypochlorite (NaOCl); 2.5%; 3%; 5%; 5.25%; 6% and 17%; 2% chlorhexidine digluconate (CHX) and 2.5% EDTA; 5%; 15% and 17% on the microhardness of root canal dentin after its use as an irrigating solution. An integrative review was carried out in the databases: PubMed, Cochrane and Lilacs, using the following descriptors in English: "irrigating solutions"; "chelaling agents"; "dentin microhardness"; "EDTA"; "sodium hypochlorite"; "chlorhexidine gluconate". The "and" connector was used, associating dentin microhardness with other descriptors. Inclusion criteria: Scientific articles in the field of dentistry, written in English and Portuguese that address the topic "Do solutions of sodium hypochlorite (NaOCl), chlorhexidine gluconate (CHX) and EDTA influence the microhardness of root dentin?". Exclusion criteria: articles repeated in more than one database, books, doctoral theses, master's dissertations, abstracts and papers published in congress. Strong evidence indicates that sodium hypochlorite, chlorhexidine gluconate and EDTA influence the microhardness of root dentin when used as an irrigating solution during endodontic treatment... (AU)

Effect of Protein-Based Treatment on Chemical Composition, Hardness and Bond Strength of Remineralized Enamel

Abstract This study evaluated the chemical composition and microhardness of human enamel treated with an Enamel Matrix Derivative (EMD) solution, and the bond strength between composite resin and this enamel. Thirty human enamel samples were randomly divided into three groups: Untouched Enamel (UE), Demineralized Enamel (DE) and Demineralized Enamel Treated with EMD (ET). DE and ET groups were subjected to acid challenge and ET treated with EMD (EMD was directly applied over conditioned enamel and left for 15 min). Samples from each group (n=4) had chemical composition assessed through to attenuated total reflectance Fourier transform infrared (ATR-FTIR). Knoop microhardness of enamel samples from each group (n=10) was measured. For the microshear bond strength, the samples were etched for 30 s, and the adhesive was applied and cured for 10 s. Two matrixes were placed on the samples, filled with Filtek Z350 XT composite and cured for 20 s, each. The matrix was removed, and the microshear bond strength of each group (n=10) was tested. Data were subjected to Kruskal-Wallis test (for microhardness), to analysis of variance and to Tukey's test (for microshear bond strength); (α=0.05). FTIR results have shown phosphate (hydroxyapatite indicator) in 900-1200 cm-1 bands in the UE and ET groups, which were different from the DE group. Microhardness and microshear analyses recorded higher statistical values for the UE and ET groups than for DE. EMD application to demineralized enamel seems to have remineralized the enamel; thus, the microhardness and bond strength was similar between UE and ET groups.

Resumo Este estudo avaliou a composição química e microdureza do esmalte humano tratado com solução de Derivados da Matriz do Esmalte (EMD) e a resistência de união entre compósito e este esmalte. Trinta amostras de esmalte humano foram aleatoriamente divididas em três grupos: Esmalte Intocado (UE), Esmalte Desmineralizado (DE) e Esmalte Desmineralizado Tratado com EMD (ET). Os grupos DE e ET foram submetidos a desafio ácido e ET tratado com EMD (O EMD foi aplicado diretamente sobre esmalte condicionado e deixado por 15 minutos). Amostras de cada grupo (n = 4) tiveram composição química avaliada através de espectroscopia no infravermelho por transformada de Fourier com reflectância total atenuada (FTIR-ATR). A microdureza Knoop das amostras de esmalte de cada grupo (n=10) foi mensurada. Para a resistência ao microcisalhamento, as amostras foram condicionadas por 30 s, o adesivo aplicado e foto-ativado por 10 s. Duas matrizes plásticas (1 mm de comprimento) foram posicionadas sobre as amostras, preenchidas com compósito Filtek Z350 XT e foto-atiavadas por 20 s cada. As matrizes foram removidas e a resistência ao microcisalhamento de cada grupo (n=10) foi testada. Os dados foram submetidos ao teste de Kruskal-Wallis (para análise da microdureza), à análise de variância e ao teste de Tukey (para análise da resistência ao microcisalhamento); (α=0.05). Os resultados do FT-IR mostraram fosfato (indicador de hidroxiapatita) na banda entre 900-1200 cm-1 nos grupos UE e ET, diferentemente do grupo DE. Análises de microdureza e microcisalhamento demonstraram resultados estatisticamente superiores para os grupos UE e ET quando comparados ao DE. A aplicação de EMD ao esmalte desmineralizado parece ter remineralizado o esmalte; assim, a microdureza e a resistência de união foram semelhantes entre os grupos UE e ET.

Effect of Resin Coating on Surface Roughness and Microhardness of High Viscous Glass Ionomer Cements

ABSTRACT@#High viscous glass ionomer cement (HVGIC) was recently developed for atraumatic restorative treatment (ART). However, its moisture sensitivity remains a limitation thus protective coating application is recommended. This study investigated the effect of resin coating on the surface roughness and microhardness of two HVGICs (Riva Self Cure HVGIC [RV] and Equia® Forte Fil [EQ]) conditioned in food-simulating liquids (FSLs). Fifty standard disc-shaped samples were fabricated using customised stainless-steel mould (10 × 2 mm). Coating was applied on top surface of all samples and subsequently divided into five groups: air (control), distilled water, 0.02 N citric acid, heptane and 50% ethanol-water solution. The samples were conditioned in FSLs at 37°C for seven days. Subsequently, the surface roughness and microhardness of samples were measured using optical profilometry and microhardness tester, respectively. SEM analysis was done for qualitative observation of surface morphological changes. Data were analysed using one-way ANOVA, two-way ANOVA and posthoc Tukey’s test (α = 0.05). Interestingly, the results revealed that surface roughness was significantly influenced by FSLs immersion, presence of coating and the materials itself (p < 0.001). The lowest surface roughness was found on control coated samples: RV (50.98±4.25) nm and EQ (62.77±3.92) nm, while the highest values seen on uncoated surfaces in citric acid: RV (505.26±31.10) nm and EQ (350.33±15.36) nm. RV samples had the lowest microhardness of 54.97±2.48 Vickers hardness number (VHN) post-immersion in citric acid. In conclusion, with the exception of RV conditioned in heptane and ethanol, the uncoated HVGICs generally had higher surface roughness than the coated HVGICs. HVGICs conditioned in citric acid showed the most significant increase in surface roughness and reduction in microhardness.