Assessment of influence of LED curing units used on microhardness of resin-modified glass ionomer sealants

Aim: Resin modified glass ionomer (RMGI) is class of material that can be used as sealant for preventing and arresting the progression of caries in pits and fissures. As these are hybrid materials, their properties can be affected by factors related to the polymerization process. Therefore, this study aimed to evaluate the influence of different generations of LED curing units (Elipar DeepCure-L and VALO Grand) on Knoop microhardness values (KHN) of RMGI sealants (Clinpro XT and Vitremer). Methods: Forty cylindrical specimens (6mm ø x 1 mm high) were prepared according to the manufacturer's instructions and divided into four groups (n=10) according to the type of RMGI and LED used. The KHN of the top surface of each sample was calculated 7 days after light-curing. Data were submitted to two-way ANOVA (α = 0.05). Results: Vitremer had higher KHN values than Clinpro XT after using both LEDs (p<0.0001), but especially when light-cured with the use of VALO Grand (p<0.0001). Whereas the KHN value of Clinpro was not influenced by the LED device (p>0.05). Conclusions: Top surface microhardness values of RGMI sealants were affected by both material composition and generations of LED curing units used. Third generation LED curing units seemed to be more efficient for the polymerization of RMGI-based sealants

Effect of conventional and power office bleaching with diode laser and led light on enamel microhardness

Aim: The present study aimed to asses enamel microhardness after office bleaching with diode laser and LED light compared to the conventional bleaching procedure. Methods: Thirty-nine human premolar teeth were collected and randomly divided into three groups regarding of the bleaching technique. Group 1: Snow O bleaching gel with LED light-curing unit; Group 2: Snow L bleaching gel with diode laser irradiation; and Group 3: Opalescence Boost bleaching gel with no light source in group 3. Enamel surface changes were evaluated in one tooth in each study group and one intact tooth as a reference under a scanning electron microscope (SEM). In the remaining samples (n=12), enamel microhardness was determined by Vickers microhardness test before and after bleaching. Data were analyzed with repeated-measures ANOVA to compare microhardness changes, followed by post hoc Tukey tests at the 0.05 significance level. Results: Enamel microhardness decreased in all the groups after bleaching, with the maximum decrease in microhardness in the Snow O bleaching group with LED light, which was significantly higher than the other groups (P=0.002). The two other groups did not exhibit any significant difference in microhardness decrease (P>0.05). Conclusion:Based on the limitations of this study, it can be concluded power bleaching with 980nm diode laser was less time-consuming compare to conventional bleaching procedure and yielded better outcomes in terms of enamel surface microhardness compared to the use of an LED light-curing unit

Influência da profundidade e de um processo de envelhecimento acelerado em propriedades de resinas bulk fill / Influence of depth and an accelerated aging process on bulk fill resin properties

O presente estudo teve como objetivo avaliar o desempenho de quatro resinas bulk fill (Filtek Bulk Fill (FBF), Opus Bulk Fill (OBF), Sonicfill (SF) e Tetric N-Ceram Bulk Fill (TNBF)) e uma resina convencional (Charisma Diamond (CD)) quanto às seguintes propriedades: resistência à flexão (RF), módulo de elasticidade (ME) e dureza Knoop (KHN) em função da profundidade e após a realização de um envelhecimento acelerado. Corpos de prova em formato de barra foram confeccionados simultaneamente em diferentes profundidades (1, 2, 3, 4 e 5 mm) para realização dos testes de resistência à flexão (n=10), módulo de elasticidade (n=10) e dureza Knoop (n=3). Os testes foram realizados em dois momentos, previamente e após a realização de um envelhecimento acelerado, que consistiu na realização de uma termociclagem com banhos alternados em água a 5 e 55ºC, com 1 min de imersão em cada, por 2000 ciclos. Os resultados para o teste de RF e ME mostraram que os valores para estas duas propriedades diminuíram em função da profundidade e após a realização da termociclagem para todas as resinas estudadas. Apenas a resina TNBF não apresentou diferença estatística para valores de ME após o envelhecimento acelerado. Quanto à dureza, os valores também diminuíram em função da profundidade, porém aumentaram após a realização do envelhecimento acelerado. Apenas a resina SF não apresentou diferença estatística entre os valores de dureza antes e após o envelhecimento. A resina convencional CD após a ciclagem térmica foi a única que apresentou relação base/topo (2 mm) acima de 80%. Nenhuma das resinas do tipo bulk fill apresentou uma relação base/topo acima de 80% para a dureza quando avaliadas na espessura máxima recomendada. Com base nos resultados obtidos, pode-se afirmar que, quando fotoativadas na espessura máxima recomendada, apenas a resina convencional CD apresentou resultados condizentes com a homogeneidade esperada em todas as condições deste estudo. Entretanto, para as resinas do tipo bulk fill, pode-se observar que as propriedades estudadas, de modo geral, sofreram uma diminuição significativa em função da profundidade. Para o envelhecimento, a dureza, diferentemente dos outros parâmetros, mostrou uma tendência de aumento.

Effect of penetrating resin on the surface structure, microhardness and color of enamel after bleaching / 中华口腔医学杂志

Objective: To investigate the effect of permeable resin on the surface structure, microhardness and color of tooth enamel after bleaching. Methods: Premolars extracted for orthodontic needs were selected (provided by the Department of Oral and Maxillofacial surgery of the first affiliated Hospital of Zhengzhou University) and randomly divided into A, B and C 3 groups. Each group was randomly divided into control subgroup, resin subgroup, bleaching subgroup and combined subgroup. Samples in the control subgroup did not receive any treatment. Those in the bleaching subgroup and combined subgroup were treated with cold light whitening. Those in the resin group and combined group were treated with permeable resin. Samples in the group A were observed by scanning electron microscope immediately after treatment and 2 weeks after treatment, and the microhardness of samples in the group B was measured before treatment, immediately after treatment and 2 weeks after treatment (the sample size of each time point was 8 in each subgroup). In group C, chromaticity was measured and chromatic aberration (ΔE value) was calculated before treatment, immediately after treatment and 1 and 2 weeks after treatment (10 samples in each subgroup). Results: Scanning electron microscope showed that the enamel surface of the resin subgroup and the combined group was smooth immediately after treatment, which was basically the same as that of the control subgroup, but covered with resin, and microporous defects and mineral deposits could be seen on the surface of the bleaching subgroup. Two weeks after treatment, the enamel surface of each subgroup was smooth, there was no obvious difference. Immediately after treatment, the microhardness of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were (354±33), (364±21), (411±30) and (350±17) HV, respectively (F=9.39,P<0.05). The microhardness of the bleaching subgroup was significantly higher than that of the other subgroups (P<0.05). There was no significant difference in microhardness among the four subgroups before treatment and 2 weeks after treatment (F=0.34, 2.75, P>0.05). Immediately after treatment, the ΔE values of the control subgroup, resin subgroup, bleaching subgroup and combined subgroup were 0.00±0.00, 2.29±1.86, 7.20±1.94 and 8.00±0.88, respectively (F=74.21,P<0.05); except that there was no significant difference between bleaching subgroup and combined subgroup (P>0.05), there were significant differences among the other subgroups (P<0.05). There was no significant difference in ΔE value among control subgroup, resin subgroup and bleaching subgroup at each time point (F=1.66, 0.30, 0.96, P>0.05). The difference in the combined subgroup immediately after treatment was significantly higher than that at 1 and 2 weeks after treatment (t=4.73, 4.23,P<0.05), but there was no significant difference between 1 and 2 weeks after treatment (t=0.75, P>0.05), and the color tended to be stable. Conclusions: When whitening healthy enamel, simple cold light whitening or cold light whitening combined with permeation resin can achieve whitening effect.

Produção de biscoitos recheados com formação de organogel na base gordurosa / Production of sandwich cookies with the formation of organogel in the fatty base

A fim de atender à demanda do público que atualmente busca por alimentos mais saudáveis, as indústrias têm procurado alternativas que possibilitem a aplicação de ingredientes que agreguem valor nutricional aos produtos. A redução de gorduras saturadas e trans em produtos alimentícios, bem como a inserção de cereais ou farinhas nutricionais, vem sendo aplicadas em produtos de panificação. Biscoitos recheados possuem como bases geralmente biscoitos à base de farinha de trigo. O objetivo foi desenvolver formulação de biscoitos recheados com substituição de gordura vegetal por organogel no recheio e de farinha de trigo por farinha de sorgo no biscoito, a fim de agregar valor nutricional ao produto. Foram desenvolvidos biscoitos recheados: 1) recheio controle e com substituição da gordura vegetal dos recheios por organogel elaborado com sistema emulsionado (colágeno + óleo vegetal + água), a fim de diminuir concentrações de gorduras saturadas e trans. 2) para a base elaborouse biscoitos controle (farinha de trigo) e com substituição parcial e total de farinha de trigo por farinha de sorgo em 50% (50FS) e 100% (100FS). Foram conduzidas nos recheios e das bases dos biscoitos análises físicas e físico-químicas (textura, atividade de água, cor, composição centesimal e reologia) para avaliação e para análise de estabilidade de 6 semanas. Os resultados apresentaram que o biscoito 50FS obteve melhor valor de textura (Controle: 16,09 ± 1,28 N; 50FS: 19,63 ± 5,68 N e 100FS: 10,09 ± 0,65 N) e menor teor de atividade de água (Semana 01: 0,327±0,01 e Semana 06: 0,389 ± 0,00) do que o biscoito controle, durante análise de estabilidade. O biscoito 100FS apresentou coloração mais avermelhada. Os biscoitos 50FS e 100FS apresentaram maior teor proteico do que o controle (Controle: 5,37 ± 0,23 %; 50FS: 5,64 ± 0,49 % e 100FS: 5,75 ± 0,49 %). O recheio com organogel apresentou maior dureza (N) durante análise de estabilidade do que o recheio controle (Semana 6 Organogel: 6,81±1,48; Controle: 4,29±0,38). Os parâmetros de adesividade, coesividade e gomosidade do recheio com organogel não apresentaram diferenças significativas (p > 0,05). Os valores de atividade de água da formulação com organogel foram mais altos do que o recheio controle (Semana 6 Organogel: 0,730±0,00; Controle: 0,555±0,01). O valor de L* foi maior para o recheio controle, apresentando coloração mais amarelada do que a formulação com organogel. O recheio com organogel apresentou redução de 65 % do teor lipídico e aumento do teor proteico. Os recheios controle, com organogel e de mercado apresentaram comportamento tixotrópico durante a avaliação reológica, sendo que o produto de mercado teve comportamento próximo à formulação controle, com recuperação quase total da estrutura. Foram desenvolvidos cinco produtos, sendo três inovadores com valor nutricional agregado, atendendo às legislações vigentes, vida útil mínima de 6 semanas e ao apelo do mercado atual, podendo ser comercializados como biscoito recheado

In order to satisfy the demand of the public that is currently looking for healthier foods industries have been looking for alternatives that allow the application of ingredients that add nutritional value to the products. The reduction of saturated and trans fats in food products, as well as the insertion of cereals or nutritional flours, has been applied in bakery products. Filled cookies are usually based on wheat flour. The objective was to develop a formulation of filled cookies with replacement of vegetable fat for organogel in the filling and wheat flour for sorghum flour in the biscuit, in order to add nutritional value to the product. In this study, cookies filled with vegetable fat and wheat flour were used as a control where: 1) filling was replaced by organogel elaborated with an emulsified system (collagen + vegetable oil + water); and 2) base was prepared with partial and total replacer of wheat flour for sorghum flour in 50% (50FS) and 100% (100FS). Physical and physicochemical analyzes (texture, water activity, color, proximate composition and rheology) were carried out on the fillings and bases of the biscuits for evaluation and for the stability analysis of 6 weeks. The results showed that the 50FS cookies had a better texture value (Control: 16,09±1,28 N; 50FS: 19,63±5,68N and 10,09±0,65 N) and lower content of water activity (Week 1: 0,327±0,01 and Week 6: 0,389±0,00) than the control cookie during stability analysis. The 100FS had a more reddish color. The 50FS and 100FS cookies had a higher protein content than the control (Control: 5,37±0,23 %; 50FS 5,64±0,49 %). The fillings with organogel showed a higher hardness (N) than the control during stability analysis (Week 6 Organogel: 6,81±1,48; Control: 4,29±0,38). The parameters of adhesiveness, cohesiveness and guminess of the filling with organogel showed no significant differences (p> 0.05). The water activity values of the organogel formulation were higher than the control filling (Week 6 Organogel: 0,730±0,00; Control: 0,555±0,01). The value of L * was higher for the control filling, showing a more yellowish color than the formulation with organogel. The filling with organogel showed a 65% reduction in lipid content and an increase in protein content. The control, organogel and market fillings showed a thixotropic behavior in the rheological evaluation, and the market product had a behavior close to the control formulation, with almost total recovery of the structure. Five products were developed, three of which were innovative with added nutritional value, in compliance with current legislation, a minimum shelf life of 6 weeks, which can be sold as a stuffed cookies.

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.

Ação da clorexidina e do hipoclorito de sódio sobre a microdureza dentinária / Action of chlorhexidine and sodium hypochlorite over dentin microhardness

Objetivo: Avaliar a microdureza do tecido dentinário bovino após a exposição a soluções irrigantes em Endodontia. Métodos: Amostras de dentina bovina foram divididas aleatoriamente em seis grupos (n=10) e submetidas aos seguintes tratamentos: soro (60 min); NaOCl a 2,5% (hipoclorito de sódio) (60 min); CHX gel a 2% (clorexidina) (60 min); EDTA a 17% (ácido etilenodiaminotetracético) (1 min); NaOCl a 2,5% + EDTA a 17% (60 + 1 min) e CHX gel a 2% + EDTA a 17% (60 + 1 min). A microdureza Knoop foi utilizada para as medidas. Os dados foram avaliados pelo teste ANOVA, seguido pelo método de Duncan, com nível de significância de 5%. Resultados: A solução de NaOCl a 2,5%, seguida ou não de EDTA a 17%, reduziu significativamente a microdureza dentinária (p<0,05). A exposição à clorexidina gel a 2%, seguida ou não de EDTA a 17%, não resultou em alterações na microdureza dentinária (p>0,05). Conclusão: NaOCl a 2,5% reduziu significativamente a microdureza da dentina bovina após 60 minutos de exposição (AU).

Objective: Evaluate the microhardness of bovine den- tin tissue after exposure to endodontic irrigating solu- tions. Methods: Bovine dentin samples were randomly divided into 6 groups (n = 10) and submitted to the following treatments: saline (60 min); 2.5% NaOCl (sodium hypochlorite) (60 min); 2% gel CHX (chlorhexidine) (60 min); 17% EDTA (Ethylenediamine tetraacetic acid) (1 min); 2.5% NaOCl + 17% EDTA (60 + 1 min) and 2% gel CHX + 17% EDTA (60 + 1 min). Knoop microhardness was used for the measurements. Data were evaluated by ANOVA test followed by Duncans Method at 5% signifi- cance level. Results: The 2.5% NaOCl solution, followed or not by 17% EDTA, significative reduced the dentin microhardness (p <0.05). Exposures to 2% gel chlorexidine, followed or not by 17% EDTA, did not result in alterations at dentin tissue microhardness (p>0.05). Conclusion: 2.5% NaOCl significatively reduces the microhardness of bovine dentin after 60 minutes of exposure (AU).

Comparación de la microdureza superficial de discos de resina acrílica de termocurado y autocurado en distintos periodos de tiempo / Comparison of the surface microhardness of heat curing and self-curing acrylic resin discs in different time periods

Objetivo: Comparar la microdureza superficial de discos de acrílico de autocurado y termocurado en distintos periodos de tiempo. Metodología: Este estudio experimental, un ensayo en laboratorio in vitro, incluyó 80 discos de acrílico (Vitalloy), 40 de autocurado (A) y 40 de termocurado (T) divididos en 8 subgrupos: grupo control de autocurado GA0 (n = 10), grupo control de termocurado GT0 (n = 10), grupo de autocurado almancenado 1 día GA1 (n = 10), grupo de termocurado almacenado 1 día GT1 (n = 10), grupo de autocurado almacenado 7 días GA7 (n = 10), grupo de termocurado almacenado 7 días GT7 (n = 10), grupo de autocurado almacenado 21 días GA21 (n = 10), grupo de termocurado almacenado 21 días GT21 (n = 10); luego se evaluó la microdureza superficial Vickers de los discos de resina acrílica previamente almacenados en suero fisiológico en los distintos periodos de tiempo. Posteriormente, los datos fueron analizados estadísticamente mediante test de Anova y Tukey. El nivel de significancia estadística se tomó como p < 0,05. Resultados: Los valores encontrados fueron en el GT0 (20,45 ± 0,93 VHN); GA0(16,25 ± 0,79 VHN); GT1 (20,08 ± 0,66 VHN); GA1 (15,97 ± 0,78 VHN); GT7 (19,57 ± 1,54 VHN); GA7 (14,33 ± 0,48 VHN); GT21 (19,17 ± 1,26 VHN); GA21 (14,64 ± 0,52 VHN), presentando diferencias estadísticamente significativas ambos grupos autocurado y termocurado (p < 0,001). Conclusión: Los grupos de resinas acrílicas de termocurado presentaron mejores valores de microdureza que los grupos de resinas acrílicas de autocurado en los distintos periodos de tiempo evaluados. (AU)

Objective: To compare surface microhardness of self-curing and heat-curing acrylic discs in different periods of time. Methodology: This in vitro laboratory study, consisted of 80 acrylic discs (Vitalloy), 40 self-cured (A) and 40 heat-cured (T) divided into 8 subgroups: self-cure control group GA0 (n=10), heat-cure control group GT0 (n=10), self-cure group stored 1 day GA1 (n=10), heat-cure group stored 1 day GT1 (n=10), self-cure group stored 7 days GA7 (n=10), heat-cure group stored 7 days GT7 (n=10), self-cure group stored 21 days GA21 (n=10), and heat-cure group stored 21 days GT21 (n=10). Vickers surface microhardness of the acrylic resin discs previously stored in physiological serum was then evaluated at the different time periods. Subsequently, the data was statistically analyzed using ANOVA and TUKEY tests. The level of statistical significance was set at P <0.05. Results: The values found were in GT0 (20.45±0.93 Vickers hardness number [VHN]); GA0 (16.25±0.79 VHN); GT1 (20.08±0.66 VHN); GA1 (15.97±0.78 VHN); GT7(19.57±1.54 VHN); GA7 (14.33±0.48 VHN); GT21 (19.17±1.26 VHN); GA21 (14.64±0.52 VHN), with statistically significant differences between the self-cure and heat-cure groups (P<0.001). Conclusion: The groups of heat-curing acrylic resins presented better microhardness values than the groups of self-curing acrylic resins in the different time periods evaluated. (AU)

Análisis cinemático de la masticación de alimentos duros y blandos en participantes dentados utilizando articulografía electromagnética 3D / Kinematic analysis of hard and soft food mastication in dentate participants using 3D electromagnetic articulography

RESUMEN: Diversos estudios reportan que el tipo de alimento influye directamente en los patrones cinemáticos de la masticación. El objetivo de este estudio fue analizar y comparar los ciclos masticatorios de participantes adultos y completamente dentados durante la masticación de alimentos de diferente textura y dureza (maní y zanahoria) utilizando articulografía electromagnética 3D. Se evaluaron 11 participantes sanos (5 hombres; 6 mujeres), de 31,9 ± 5,2 años de edad. Mediante articulografía electromagnética 3D, se registró la masticación de dos alimentos de prueba (maní y zanahoria). Los datos de movimiento mandibular fueron procesados con MATLAB® y obteniendo diferentes parámetros-frecuencia masticatoria en ciclos por segundo, velocidad de descenso y ascenso mandibular, área de las proyecciones de cada ciclo masticatorio en los tres planos del espacio-que fueron comparados según tipo de alimento y género de los participantes. Se encontraron diferencias estadísticamente significativas entre las áreas de los ciclos masticatorios en el plano horizontal según tipo de alimento, siendo mayor para la masticación de zanahoria (P=,003). Así mismo, se detectaron diferencias estadísticamente significativas entre las áreas sagitales de los ciclos entre hombres y mujeres, siendo mayor en mujeres (P=,042). Nuestros resultados concuerdan con otros estudios que afirman que la textura del alimento influye en las características cinemáticas de los ciclos masticatorios.

SUMMARY: Several studies report that the type of food directly influences the kinematic patterns of mastication. The aim of this study was to analyze and compare the chewing cycles of adult and fully dentate participants during the mastication of foods of different texture and hardness (peanuts and carrots) using 3D electromagnetic articulography. Eleven healthy participants (5 men; 6 women), 31.9 ± 5.2 years old, were evaluated. By means of 3D electromagnetic articulography, the mastication of two test foods (peanuts and carrots) was recorded. The data associated to mandibular movement were processed with MATLAB® obtaining different parameters-masticatory frequency in cycles per second, mandibular descent and ascent rate, area of the projections of each masticatory cycle in the three planes of space-which were compared according to type of food and sex of the participants. Statistically significant differences were found between the areas of the masticatory cycles in the horizontal plane according to type of food, being greater for carrots (P=.003). Likewise, statistically significant differences were detected between the sagittal areas of the cycles between men and women, being greater in women (P=.042). Our results agree with other studies that affirm that the texture of the food influences the kinematic characteristics of the masticatory cycles.

Light transmittance and depth of cure of a bulk fill composite based on the exposure reciprocity law

Abstract The objective of this study was to evaluate the effect of the exposure reciprocity law of a multi-wave light-emitting diode (LED) on the light transmittance (LT), depth of cure (DOC) and degree of conversion in-depth (DC) of a bulk fill composite. A bulk fill composite (EvoCeram® bulk fill, Ivoclar Vivadent) was photoactivated using the multi-wave LED (VALO™ Cordless, Ultradent). The LED was previously characterized using a spectrophotometer to standardize the time of exposure when using the Standard or Xtra-Power modes with the same radiant exposure of 20J/cm2. LT was evaluated through samples of the bulk fill composite every millimeter till 4 mm in-depth. DOC was evaluated according to the ISO 4049. DC of the central longitudinal cross-section from each sample of the DOC test was mapped using FT-NIR microscopy. Data were statistically analyzed according to the experimental design (α=0.05; ß=0.2). The radiant exposure in the violet wavelength range for Standard and Xtra-Power was 4.5 and 5.0 J/cm2, respectively; for the blue wavelength range the radiant exposure for Standard and Xtra-Power was 15.5 and 15.0 J/cm2, respectively. There was no statistical difference in the DOC using Standard or Xtra-Power light-curing modes, but the DOC was lower than the claimed by the manufacturer (4 mm). The DC was not significantly affected by the light-curing mode up to 4 mm in depth (p>0.05). According to exposure reciprocity law, the reduction in exposure time using the same radiant exposure did not affect the depth of cure of the bulk fill composite.

Resumo O objetivo deste estudo foi avaliar o efeito da lei de reciprocidade de um diodo emissor de luz (LED) multi-wave na transmitância de luz (LT), profundidade de cura (DOC) e grau de conversão em profundidade (DC) de um compósito bulk fill. Material e Métodos: Um compósito bulk fill (EvoCeram®, Ivoclar Vivadent) foi fotoativado utilizando um LED multi-wave (VALO ™ Cordless, Ultradent). O LED foi previamente caracterizado usando um espectrofotômetro para padronizar o tempo de exposição utilizando os modos Standard ou Xtra-Power com a mesma dose de energia de 20 J/cm 2. A LT foi avaliada através de amostras do compósito bulk fill a cada milímetro até 4 mm de profundidade. O DOC foi avaliado de acordo com a ISO 4049. O DC foi realizado em forma de mapeamento da seção transversal longitudinal central de cada amostra do teste de DOC utilizando microscopia FT-NIR. Os dados foram analisados estatisticamente de acordo com o delineamento experimental (α=0,05; ß=0,2). A exposição radiante na faixa de comprimento de onda violeta para os modos Standard e Xtra-Power foi de 4,5 e 5,0 J/cm2, respectivamente; e para a faixa de comprimento de onda azul, a exposição radiante para os modos Standard e Xtra-Power foi de 15,5 e 15,0 J/cm2, respectivamente. Não houve diferença estatística no DOC utilizando os modos de fotopolimerização Standard ou Xtra-Power, mas o DOC foi menor do que o reivindicado pelo fabricante (4 mm). O DC não foi afetado significativamente pelo modo de fotopolimerização até 4 mm de profundidade (p>0,05). De acordo com a lei de reciprocidade da exposição, a redução no tempo de exposição utilizando a mesma exposição radiante não afetou a profundidade de cura do compósito bulk fill.

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.

Análise in vitro da capacidade de soluções contendo fluoreto e/ou hexametafosfato na remineralização da dentina / In vitro analysis of the capacity of solutions containing fluoride and/or hexametaphosphate on the remineralization of dentin

O objetivo do presente estudo foi avaliar a capacidade de soluções contendo HMP e F, sozinhos ou em associação, em induzir a remineralização dentinária em um protocolo in vitro. Blocos de dentina radicular bovina (4 × 6 cm, n = 100) foram preparados e submetidos à indução de lesões de cárie artificiais em dois terços da superfície; cada bloco foi utilizado como seu próprio controle. Em seguida, os blocos foram divididos em 10 grupos experimentais (n=10/grupo), de acordo com as soluções a serem testadas: (1) Placebo (sem F ou HMP); (2) 0,5% HMP; (3) 0,75% HMP; (4) 1% HMP; (5) 250 ppm F; (6) 500 ppm F; (7) 1100 ppm F; (8) 250 ppm F + 0,5% HMP; (9) 500 ppm F + 0,75% HMP e (10) 1100 ppm F + 1% HMP. Os blocos foram tratados por um minuto, duas vezes ao dia com as respectivas soluções, e submetidos a uma ciclagem de pH durante 7 dias. Em seguida, foram determinadas a porcentagem de recuperação da dureza de superfície (%RDS) e a área integrada da lesão de subsuperfície (ΔKHN). Os dados foram submetidos a ANOVA e teste de Fisher LSD (p<0.05). Uma relação dose-reposta foi observada entre as concentrações de F nas soluções sem HMP e as variáveis %RDS e ΔKHN; quanto às soluções contendo apenas HMP, uma relação dose-resposta foi observada somente para ΔKHN. Em relação à %RDS, os grupos placebo e 0,5% HMP, e os grupos 0,75% e 1% HMP não apresentaram diferenças significativas entre si. Quando associado ao F, o HMP aumentou a capacidade de remineralização da superfície e subsuperfície dentinária, visto que os grupos contendo F + HMP apresentaram resultados significativamente melhores em relação aos grupos contendo F sozinho. Em acréscimo, a solução contendo 250 ppm F + 0,5% HMP promoveu um efeito remineralizador semelhante à solução contendo 500 ppm F. Já em relação à ∆KHN, diferenças estatísticas foram observadas entre todos os grupos na área tratada, sem diferenças significativas quanto às áreas controle e desmineralizada. Os resultados permitem concluir que a adição de HMP às soluções fluoretadas potencializou o efeito destas sobre a remineralização das lesões artificiais de cárie em dentina, tanto na superfície quanto em profundidade(AU)

The present study aimed to investigate the ability of solutions containing HMP and F, alone or in association, in promoting dentin remineralization in an in vitro protocol. Bovine root dentin blocks (4 × 6 cm, n = 100) were prepared, and caries-like lesions were induced in two thirds of the surface; each block served as its own control. Then, blocks were divided into 10 experimental groups (n = 10 / group), according to the solutions to be tested: (1) Placebo (without F or HMP); (2) 0.5% HMP; (3) 0.75% HMP; (4) 1% HMP; (5) 250 ppm F; (6) 500 ppm F; (7) 1100 ppm F; (8) 250 ppm F + 0.5% HMP; (9) 500 ppm F + 0.75% HMP and (10) 1100 ppm F + 1% HMP. Specimens were treated for one minute, twice a day with the respective solutions, and subjected to a pH-cycling regime for 7 days. Next, the percentage of the superficial hardness recovery (%SHR) and integrated loss of subsurface hardness (ΔKHN) were determined. Data were submitted to ANOVA and Fisher LSD's test (p<0.05). A dose-response relationship was observed between F concentrations in solutions without HMP and the variables %SHR and ΔKHN; as for the solutions containing HMP alone, a dose-response relationship was only observed for ΔKHN. Regarding %SHR, no significant differences were observed Placebo and 0.5% HMP groups, nor between 0.75% and 1% HMP groups. When associated with F, HMP was shown to increase the remineralizing capacity of the solutions both at the surface and the subsurface of dentin specimens, since the groups containing F + HMP showed significantly superior results compared to groups containing F alone. In addition, the solution containing 250 ppm F + 0.5% HMP promoted a remineralizing effect similar to that containing 500 ppm F. Regarding ∆KHN, significant differences were observed among all groups in the treated area, while no significant differences were observed among the groups in the control and demineralized areas. The results allowed the conclusion that the addition of HMP to fluoridated solutions significantly enhanced their remineralizing potential on dentin artificial caries lesions, both at the surface and in depth(AU)

Influence of radiant exposure values from two third generation LED curing units on polymerization profile and microhardness of orthodontic composite under ceramic and metallic brackets

ABSTRACT Introduction: Third generation of LED light curing units might be used in short exposure periods for orthodontic brackets bonding. Objective: This study evaluated the effect of the different radiant exposure (RE) values: Manufacturers' instructions (MI), ½ MI, 1/4 MI and Turbo mode. Two third-generation LED curing units were used: VALO® and Bluephase 20i® . The degree of conversion (DC) and Vickers hardness (VHN) of an orthodontic composite (OC) (Transbond XT) under metallic (MB) or ceramic brackets (CB) were measured. Methods: OC was applied to the bracket base, which was then placed over an attenuated total reflectance (ATR) table coupled to an infrared light spectroscope, or to a glass surface for the VHN analysis. The specimens were light-cured and DC values were calculated. The VHN was obtained in a microhardness tester. The data were analyzed with 2-way ANOVA followed by Tukey's post-hoc test (pre-set α=0.05). Linear regression analysis evaluated the relationship between RE values and dependent variables. Results: CB allowed higher DC and VHN values than MB (p< 0.001). No significant difference was noted among groups when CB were used. For MB, MI groups showed the highest DC and VHN values. A significant, but weak relationship was found between delivered RE values and dependent variables. Conclusions: The decrease in RE values from third generation LED CU did not jeopardize the DC values when CB were used, but can compromise DC and VHN values when MB are used.

RESUMO Introdução: A terceira geração de LEDs fotopolimerizadores pode ser utilizada em curtos períodos de exposição para a colagem de braquetes ortodônticos. Objetivo: O presente estudo avaliou o efeito dos diferentes valores de irradiância (IR): instruções do fabricante (IF), ½ IF, » IF e modo Turbo. Dois fotopolimerizadores LED de terceira geração (VALO® e Bluephase20i®) foram utilizados. Foram mensurados o grau de conversão (GC) e a dureza Vickers (VHN) de um compósito ortodôntico (CO) (Transbond XT) sob braquetes metálicos (BM) ou cerâmicos (BC). Métodos: O compósito ortodôntico foi aplicado na base do braquete e foi posicionado sobre uma mesa de refletância total atenuada (ATR) acoplada a um espectroscópio de infravermelho ou a uma superfície de vidro para análise de VHN. As amostras foram fotopolimerizadas e os valores de GC foram calculados. O VHN foi obtido em um microdurômetro. Os dados foram analisados com ANOVA de 2 fatores seguida do teste post-hoc de Tukey (predefinido α = 0,05). A análise de regressão linear avaliou a relação entre os valores de IR e as variáveis dependentes. Resultados: BC permitiu valores maiores de GC e VHN do que BM (p<0,001). Nenhuma diferença significativa foi observada entre os grupos quando BC foi utilizado. Para BM, os grupos de IF mostraram os maiores valores de GC e VHN. Uma relação significativa, mas fraca, entre os valores de IR entregue e as variáveis dependentes foi encontrada. Conclusões: A diminuição dos valores de IR dos fotopolimerizadores LED de terceira geração não prejudicou os valores de GC quando BC foram utilizados, mas pode comprometer os valores de GC e VHN quando BM são utilizados.

Synthesis of a chitosan nanoparticle suspension and its protective effects against enamel demineralization after an in vitro cariogenic challenge

Abstract Objective Our study aims to synthesize, characterize, and determine the effects of a ChNPs suspension on human enamel after cariogenic challenge via pH-cycling. Methodology ChNPs were synthesized by ion gelation and characterized by Transmission Electron Microscopy (TEM) and Dynamic Light Scattering. Forty enamel blocks were divided into four groups (n=10/group): (i) ChNPs suspension; (ii) chitosan solution; (iii) 0.05% sodium fluoride (NaF) solution; and (iv) distilled water. Specimens were exposed to cariogenic challenge by cycling in demineralization solution (3 h) and then remineralized (21h) for 7 days. Before each demineralization cycle, the corresponding solutions were passively applied for 90 s. After 7 days, specimens were examined for surface roughness (Ra) and Knoop hardness (KHN) before and after the cariogenic challenge; % KHN change (variation between initial and final hardness), and surface topography by an optical profilometer. The data were analyzed by repeated-measures ANOVA, One-way ANOVA, and Tukey tests (α=0.05). Results TEM images showed small spherical particles with diameter and zeta potential values of 79.3 nm and +47.9 mV, respectively. After the challenge, all groups showed an increase in Ra and a decrease in KHN values. Optical profilometry indicated that ChNPs- and NaF-treated specimens showed uneven roughness interspersed with smooth areas and the lowest %KHN values. Conclusion The ChNPs suspension was successfully synthesized and minimized human enamel demineralization after a cariogenic challenge, showing an interesting potential for use as an oral formulation for caries prevention.

In vivo effect of fluoride combined with amoxicillin on enamel development in rats

Abstract Some evidence in vitro suggested that amoxicillin and fluoride could disturb the enamel mineralization. Objective: To assess the effect of amoxicillin and of the combination of amoxicillin and fluoride on enamel mineralization in rats. Methodology: In total, 40 rats were randomly assigned to four groups: control group (CG); amoxicillin group (AG - amoxicillin (500 mg/kg/day), fluoride group (FG - fluoridated water (100 ppm -221 mg F/L), and amoxicillin + fluoride group (AFG). After 60 days, the samples were collected from plasma and tibiae and analyzed for fluoride (F) concentration. The incisors were also collected to determine the severity of fluorosis using the Dental Fluorosis by Image Analysis (DFIA) software, concentration of F, measurements of enamel thickness, and hardness. The data were analyzed by ANOVA, Tukey's post-hoc test, or Games-Howell post-hoc test (α=0.05). Results: Enamel thickness of the incisors did not differ statistically among the groups (p=0.228). Groups exposed to fluoride (AFG and FG) have higher F concentrations in plasma, bone and teeth than those not exposed to fluoride (CG and AG). The groups showed a similar behavior in the DFIA and hardness test, with the FG and AFG groups showing more severe fluorosis defects and significant lower hardness when compared with the AG and CG groups, with no difference from each other. Conclusion: The rats exposed to fluoride or fluoride + amoxicillin developed dental fluorosis, while exposure to amoxicillin alone did not lead to enamel defects.

Physical-mechanical properties of bulk fill composites submitted to biodegradation by streptococcus mutans

Abstract The aim of this study was to evaluate the Streptococcus mutans biofilm influence on the roughness (Ra), gloss (GU), surface hardness (KHN) and flexural strength (FS) of high viscosity bulk fill composites. Filtek Bulk Fill (FBF), Tetric N Ceram Bulk Fill (TNC), X-tra fil Bulk Fill (XF) and Filtek Z350 (FZ) were used. Ten discs of each composite were prepared for Ra, KHN and GU and 20 bars for the FS. After 24 h, specimens were polished and initial analyzes performed. Samples were sterilized and subjected to biodegradation for 7 days and final analyzes performed. Representative samples of each group were evaluated in Scanning Electron Microscope. Data were submitted to ANOVA two factors and Tukey test. XF presented the highest values (p<0.05) of Ra before and after biodegradation (0.1251; 0.3100), and FZ (0.1443) the lowest after biodegradation (p<0.05). The highest GU values (p<0.05) were observed for FZ (71.7; 62) and FBF (69.0; 64.6), and the lowest (p<0.05) for TNC (61.4; 53.3) and XF (58.5; 53.5), both before and after biodegradation. For KHN the highest values were obtained by XF (151.7; 106), and the (p< 0.05) lowest values for TNC (62.2; 51.8), both before and after biodegradation. The highest values (p<0.05) of FS were observed for FZ (127.6) and the lowest (p<0.05) for TNC (86.9); after biodegradation, XF (117.7) presented the highest (p<0.05) values compared to TNC and FZ." In conclusion, biodegradation increased Ra and decreased GU and KHN for all. Concerning FS, degradation provided a significant decreased value only for FZ.

Resumo O objetivo deste estudo foi avaliar a influência do biofilme de S. mutans na rugosidade (Ra), brilho (GU), dureza superficial (KHN) e resistência à flexão (FS) de compósitos de Bulk Fill de alta viscosidade. Foram utilizados Filtek Bulk Fill (FBF), Tetric N Ceram Bulk Fill (TNC), X-tra fil Bulk Fill (XF) e Filtek Z350 (FZ). Dez discos de cada compósito foram preparados para Ra, KHN e GU e 20 barras para o FS. Após 24 h, os espécimes foram polidos e as análises iniciais realizadas. As amostras foram esterilizadas e submetidas a biodegradação por 7 dias e as análises finais foram realizadas. Amostras representativas de cada grupo foram avaliadas no Microscópio Eletrônico de Varredura. Os dados foram submetidos à ANOVA dois fatores e teste de Tukey. XF apresentou os maiores valores (p<0,05) de Ra antes e após a biodegradação (0,1251; o00,3100) e FZ (0,1443) os menores após a biodegradação (p<0,05). Os maiores valores de GU (p<0,05) foram observados para FZ (71,7; 62) e FBF (69,0; 64,6), e os mais baixos (p<0,05) para TNC (61,4; 53,3) e XF (58,5; 53,5), ambos antes e depois da biodegradação. Para KHN, os valores mais altos foram obtidos por XF (151,7; 106), e os (p<0,05) valores mais baixos para TNC (62,2; 51,8), antes e depois da biodegradação. Os maiores valores (p <0,05) de FS foram observados para a FZ (127,6) e os menores (p<0,05) para a TNC (86,9); após biodegradação, o XF (117,7) apresentou os maiores valores (p<0,05) em comparação ao TNC e FZ. Em conclusão, a biodegradação aumentou o Ra e diminuiu a GU e a KHN para todos. Em relação à FS, a degradação promoveu uma diminuição significativa apenas para a FZ.

Effect of the addition of manioc starch, water and inulin on the technological characteristics of bicuda pâté (Sphyraena tome, Fowler, 1903) / Efecto de la adición de almidón de mandioca, agua e inulina sobre las características tecnológicas del paté bicuda (Sphyraena tome, Fowler, 1903)

Fish and fish products are an outstanding source of essential protein and micronutrients. In cured meats, such as pâté, the technological characteristics are fundamental to the final quality of the product. The present study aimed to evaluate the effect of the addition of manioc starch, water and inulin on moisture, water holding capacity (WHC) and texture profile in pâtés using the underutilized marine fish bicuda (barracuda, Sphyraenatome) with total fat replacement by inulin. A Rotational Central Composite Design (RCCD) was used with the independent variables inulin, manioc starch, and water. Water, inulin, and manioc starch significantly influenced (p<0.05) the moisture content of pâtés, WHC, and texture, hardness, gumminess, and chewiness parameters. The technological action of inulin as a substitute for fat used in the formulations (3% to 6%) was underestimated. The percentages used were below perecentages of at least 20% of fat reported in the literature.Current legislation does not recommend WHR values and hardness parameters, only values for humidity. There is a need for revision of legislation to meet the characteristics of the identity pattern and quality of fish pâté.

El pescado y los productos pesqueros son una fuente excepcional de proteínas esenciales y micronutrientes. En embutidos (carne curada) como el paté, las características tecnológicas son fundamentales para la calidad final del producto. El presente estudio tuvo como objetivo evaluar el efecto de la adición de almidón de mandioca, agua e inulina sobre la humedad, la capacidad de retención de agua (WHC) y el perfil de la textura en patés fabricados con peces marinos subutilizados (barracuda, Sphyraena tome) con reemplazo total de grasa por inulina. Se utilizó un diseño compuesto central rotatorio (RCCD) con las variables independientes inulina, almidón de mandioca y agua. El agua, la inulina y el almidón de mandioca influyeron significativamente (p<0.05) en el contenido de humedad de los patés, WHC, y los parámetros de textura, dureza, gomosidad y masticabilidad. Se subestimó la acción tecnológica de la inulina como sustituto de la grasa en los contenidos utilizados en las formulaciones (3% a 6%). Los porcentajes utilizados estaban por debajo de lo que informa la literatura de al menos un 20% de grasa. La legislación actual no recomienda valores de WHR y parámetros de dureza, solo valores de humedad. Es necesario revisar la legislación para cumplir con las características del patrón de identidad y la calidad del paté de pescado.

Surface deterioration of indirect restorative materials

Abstract The objective of this work was to evaluate the effects of in vitro and in situ biodegradation on the surface characteristics of two resin cements and a hybrid ceramic system. One hundred and eighty specimens (4X1.5mm) of each material (Maxcem Elite, NX3 Nexus and Vita Enamic) were made and randomly distributed in twelve groups (n=15) according to the material and biodegradation method. The specimens were then submitted to the following challenges: storage in distilled water 37 ºC for 24 h or 7 days, storage for 7 days, at 37 ºC, in stimulated saliva or in situ. The in situ stage corresponded to the preparation of 15 intraoral palatal devices, used for 7 days. Each device presented 3 niches, where a sample of each materials was accommodated. Specimens from both saliva and in situ groups suffered a cariogenic challenge, corresponding to the application of a solution of 20% of sucrose, 10 times throughout each day. After each biodegradation method, the surface roughness (Ra), Vickers hardness (VHN) and scanning electron microscopy (SEM) analyzes were performed. The data collected were evaluated by Levene test, two-way ANOVA and Tukey`s test (α=5%). The in situ challenge promoted the greater biodegradation, regardless of the material. Regarding the materials, the Vita Enamic VHN was negatively affected by all biodegradation methods and the Nexus NX3 presented better performance than the self-adhesive cement tested. Therefore, within the conditions of this work, it was concluded that in situ biodegradation can affect negatively the surface characteristics of indirect restorative materials.

Resumo O objetivo deste trabalho foi avaliar os efeitos da biodegradação in vitro e in situ nas características superficiais de dois cimentos resinosos e de um sistema cerâmico híbrido. Cento e oitenta espécimes (4X1,5mm) de cada material (Maxcem Elite, NX3 Nexus e Vita Enamic) foram distribuídos aleatoriamente em doze grupos (n=15) de acordo com o material e o método de biodegradação. Os espécimes foram então submetidos aos seguintes desafios: armazenamento em água destilada 37ºC por 24 horas ou 7 dias, armazenamento por 7 dias, a 37ºC, em saliva estimulada ou in situ. O estágio in situ correspondeu à preparação de 15 dispositivos intra-orais palatinos, utilizados por 7 dias. Cada dispositivo apresentou 3 nichos, onde uma amostra de cada material foi acomodada. As amostras dos grupos saliva e in situ sofreram um desafio cariogênico, correspondendo à aplicação de uma solução de 20% de sacarose, 10 vezes ao longo de cada dia. Após cada método de biodegradação, foram realizadas as análises de rugosidade superficial (Ra), dureza Vickers (VHN) e microscopia eletrônica de varredura (MEV). Os dados coletados foram analisados por meio do teste de Levene, ANOVA two-way e teste de Tukey (α=5%). O desafio in situ promoveu maior degradação, independentemente do material. Em relação aos materiais, a VHN do Vita Enamic foi afetada negativamente por todos os métodos de degradação e o Nexus NX3 apresentou melhor desempenho que o cimento autoadesivo testado. Portanto, dentro das condições deste trabalho, concluiu-se que a biodegradação in situ pode afetar negativamente as características superficiais de materiais restauradores indiretos.

Can surface protection prevent the loss of hardness on dentin and composite resin surfaces exposed to erosive challenges? / ¿Puede la protección de la superficie prevenir la pérdida de dureza en las superficies de dentina y resina compuesta expuestas a erosión?

Objective: This study investigated the effect of endogenous erosion on the microhardness of dentine and a nanofilled composite resin. Procedures for preventing erosion were also studied. Materials and Methods: 90 bovine dentine specimens were divided into three groups in accordance with the method for preventing: negative control, topical application of fluoride and resin-modified glass ionomer varnish. 120 composite resin specimens were distributed into four groups, which also included a resin sealant, among the preventive procedures. Specimens were then randomly divided into three sub-groups according to the exposure to simulate gastric acid solution and subsequent remineralization: negative control, 9 and 18 cycles. Surface analysis was carried out by measuring the Knoop hardness. The data obtained were statistically analyzed using 2-way ANOVA and Tukey test. Result: The mean hardness of dentine and of the composite specimens resin exhibited lower hardness after 18 cycles. However, the resin-modified glass ionomer varnish resulted in greater values compared to the other preventive procedures. Conclusion: A resin-modified glass ionomer varnish seems to be a promising method for minimizing the damage caused by endogenous acid, but its protection can be reduced depending on the intensity of the erosive challenge.

Objetivo: Este estudio investigó el efecto de la erosión endógena sobre la microdureza de la dentina y una resina compuesta de nanorrelleno. También se estudiaron los procedimientos para prevenir la erosión. Materiales and Métodos:90 muestras de dentina bovina se dividieron en tres grupos de acuerdo con el método para prevenir: control negativo, aplicación tópica de fluoruro y barniz de ionómero de vidrio modificado con resina. Se distribuyeron 120 muestras de resina compuesta en cuatro grupos, que también incluían un sellador de resina, entre los procedimientos preventivos. Las muestras se dividieron al azar en tres subgrupos de acuerdo con la exposición para simular la solución de ácido gástrico y la remineralización posterior: control negativo, 9 y 18 ciclos. El análisis de la superficie se realizó midiendo la dureza Knoop. Los datos obtenidos se analizaron estadísticamente mediante ANOVA de 2 vías y prueba de Tukey. Resultados: La dureza media de la dentina y de la resina de muestras compuestas exhibió una dureza más baja después de 18 ciclos. Sin embargo, el barniz de ionómero de vidrio modificado con resina resultó en valores mayores en comparación con los otros procedimientos preventivos. Conclusión: Un barniz de ionómero de vidrio modificado con resina parece ser un método prometedor para minimizar el daño causado por el ácido endógeno, pero su protección puede reducirse dependiendo de la intensidad del desafío erosivo.