Surface roughness of a resin composite / Rugosidade superficial de resina composta

ABSTRACT Objective: The aim of the present study was to evaluate the surface roughness (Ra) of the Z-350 resin composite following immersion in different media (distilled water, coca-cola, coffee, black tea and red wine). Methods: Fifty specimens of resin composite measuring 10 mm x 2 mm were prepared. Polymerization was performed using the conventional method (40 s). Each specimen was immersed for one hour per day. Evaluations were performed at baseline as well as after three, six, nine and 12 months. Three Ra readings were taken in opposite directions at each evaluation using a roughness meter. Mean Ra values were subjected to analysis of variance (ANOVA) followed by Tukey's test (p < 0.05). Results: A significant increase in Ra was found in the specimens submitted to coffee, coca-cola(r) and black tea between baseline and the three-month evaluation. Variance was also found among the remaining evaluation times (3 months to 12 months), but the differences did not achieve statistical significance. No statistically significant differences in Ra were found among evaluation times in the specimens submitted to red wine or distilled water. Conclusion: Based on the present findings, coca-cola, coffee and black tea exert an influence on the surface roughness of resin composites.

RESUMO Objetivo: Avaliar a rugosidade da superfície (Ra) do Z-350 resina composta após imersão em diferentes meios (água destilada, coca-cola, café, chá preto e vinho tinto). Métodos: Foram preparados cinquenta espécimes de resina composta medindo 10 mm x 2 mm. A polimerização foi realizada através do método convencional (40 s). Cada espécime foi imerso durante uma hora por dia. As avaliações foram realizadas na linha de base, bem como após três, seis, nove e 12 meses. Três leituras Ra foram levados em direções opostas em cada avaliação, utilizando um medidor de rugosidade. Os valores médios de Ra foram submetidos a análise de variância (ANOVA) seguido pelo teste de Tukey (p <0,05). Resultados: Um aumento significativo na Ra foi encontrada nas amostras submetidas ao café, coca-Cola(r) e chá preto entre o início e a avaliação de três meses. Variância também foi encontrado entre as épocas de avaliação restantes (3 meses a 12 meses), mas as diferenças não atingiram significância estatística. Não houve diferenças estatisticamente significativas na Ra encontrados entre os momentos de avaliação nos casos submetidos ao vinho tinto ou água destilada. Conclusão: Com base nos achados, coca-cola, café e chá preto exercem uma influência sobre a rugosidade superficial de resinas compostas.

One-year clinical evaluation of the retention of resin and glass ionomer sealants on permanent first molars in children

Abstract Aim : To compare the retention of glass ionomer cement (GIC) used as fissure sealant with a resinbased sealant. Methods: Six- to nine-year-old children (n=96) with all permanent first molars in occlusion were examined and assigned to two groups: GIC sealant or resin-based sealant. The sealants were applied according to the manufacturers' recommendations. The assessment of sealant retention was performed at two-month interval sessions (n=6), when each sample was scored according to the following criteria: complete retention, partial retention or complete loss. The visual and tactile examinations were carried out with a WHO probe, mouth mirror, air syringe and artificial light. The data were submitted to descriptive statistics and survival analysis. Results: A total of 384 occlusal surfaces were analyzed. Independent of the tooth and evaluation time, slightly better results were achieved by the resin-based sealant, but the difference was not statistically significant. Conclusions: GIC and resin-based sealants achieved similar results with regards to retention during a one-year follow-up period.

The relationship between masticatory and swallowing behaviors and body weight.

The present study aimed to compare the main objective parameters of mastication among individuals with different body mass indexes. One hundred and sixty participants matched for gender and age were divided in the following groups according to their body mass index (BMI): Obese group (30 ≤ BMI < 35), Overweight group (25 ≤ BMI < 30), normal range group (18.5 ≤ BMI < 25) and underweight group (17 ≤ BMI < 18.5). Each group was composed by forty subjects. The maximum bite force, the masticatory performance, chewing rate and three variables related to swallowing (number of chewing cycles, chewing time, and median particle size) were assessed in all groups. The oral conditions, including the number of teeth, number of occlusal units and salivary flow (unstimulated and stimulated) were also evaluated. Regardless of the BMI, males had a larger bite force and better masticatory and swallowing performances than females. They also chewed faster than females. Individuals of the obese group had the largest median particles sizes (both after 20 chewing cycles and at the moment of swallowing), which indicates a less good masticatory performance. The median particle sizes were negatively correlated with the number of teeth and number of occlusal units in the obese group. We did not observe large differences in masticatory performance and swallowing variables among the four weight groups, although there was a tendency that individuals of the obese group swallowed larger particles. The results of this study do not support the existence of an "obese chewing style".

Flexural strength of a composite resin light cured with different exposure modes and immersed in ethanol or distilled water media.

AIM: The aim of this in vitro study was to evaluate the flexural strength of a composite resin polymerized with three different modes of light exposure. MATERIALS AND METHODS: The three different modes of light exposure were conventional, 600 mW/cm2/40s; soft start, 300 mW/cm2/10s + 600 mW/cm2/30s; pulse delay, 600 mW/cm2/1s + 60 s of waiting time + 600 mW/cm2/39s). Twenty samples were prepared for each polymerization method. Flexural strength (FS) tests were carried out with a 2 kN load at a speed of 0.5 mm/ min. All tested groups were submitted to analysis of variance (one-way-ANOVA) and Tukey's test (P < 0.05). RESULTS: When stored in water, conventional and pulse delay groups presented higher FS values which were statistically different from the soft start group. When stored in 100% ethanol, conventional and soft start groups presented higher FS values which were statistically different from the pulse delay group. CONCLUSION: Different polymerization modes and immersion media can affect the physical properties (flexural strength) of composite resin.

Effect of ceramic surface treatment on the shear bond strength of a resin cement to different ceramic systems.

This study evaluated three surface treatments and their effect on the shear bond strength between a resin cement and one of three ceramics. The ceramic surfaces were evaluated with scanning electron microscopy (SEM) as well. Specimens were treated with 50 µm aluminum oxide airborne particles, 10% hydrofluoric acid etching, or a combination of the two. Using a matrix with a center hole (5.0 mm x 3.0 mm), the ceramic bonding areas were filled with resin cement following treatment. The specimens were submitted to thermal cycling (1,000 cycles) and the shear bond strength was tested (0.5 mm/minute). The failure mode and the effect of surface treatment were analyzed under SEM. Data were submitted to ANOVA and a Tukey test (α = 0.05). Duceram Plus and IPS Empress 2 composite specimens produced similar shear bond strength results (p > 0.05), regardless of the treatment method used. Hydrofluoric acid decreased the shear bond strength of In-Ceram Alumina specimens. For all materials, surface treatments changed the morphological surface. All treatments influenced the shear bond strength and failure mode of the ceramic/resin cement composites.

Effects of different surface treatments and accelerated artificial aging on the bond strength of composite resin repairs.

The purpose of the present study was to assess the bond strength of composite resin repairs subjected to different surface treatments and accelerated artificial aging. 192 cylindrical samples (CSs) were prepared and divided into 24 groups (n = 8). Half of the CSs were stored in water for 24 h, and the other half were subjected to C-UV accelerated aging for non-metallic specimens. The treatments were phosphoric acid + silane + adhesive (PSA); phosphoric acid + adhesive (PA); diamond bur + phosphoric acid + silane + adhesive (DPSA); diamond bur + phosphoric acid + adhesive (DPA); air abrasion + phosphoric acid + silane + adhesive (APSA); and air abrasion + phosphoric acid + adhesive (APA). The repair was performed and the specimens were again aged as described above. A control group (n = 8) was established and did not receive any type of aging or surface treatment. The specimens were loaded to failure in shear mode with a crosshead speed of 0.5 mm/min until fracture. Data were analyzed by one-way ANOVA/Tukey's test (p < 0.05). No statistically significant differences were found among DPSA, DPA, APSA, APA, and the control group. The aged PSA and PA achieved low bonding values and were statistically different from the control group, whereas the non-aged PSA and PA presented no statistically significant difference from the control group. Repairs with the proposed surface treatments were viable on both recent and aged restorations; however, phosphoric acid + adhesive alone were effective only on recent restorations.

Effects of different surface treatments and accelerated artificial aging on the bond strength of composite resin repairs

The purpose of the present study was to assess the bond strength of composite resin repairs subjected to different surface treatments and accelerated artificial aging. 192 cylindrical samples (CSs) were prepared and divided into 24 groups (n = 8). Half of the CSs were stored in water for 24 h, and the other half were subjected to C-UV accelerated aging for non-metallic specimens. The treatments were phosphoric acid + silane + adhesive (PSA); phosphoric acid + adhesive (PA); diamond bur + phosphoric acid + silane + adhesive (DPSA); diamond bur + phosphoric acid + adhesive (DPA); air abrasion + phosphoric acid + silane + adhesive (APSA); and air abrasion + phosphoric acid + adhesive (APA). The repair was performed and the specimens were again aged as described above. A control group (n = 8) was established and did not receive any type of aging or surface treatment. The specimens were loaded to failure in shear mode with a crosshead speed of 0.5 mm/min until fracture. Data were analyzed by one-way ANOVA/Tukey's test (p < 0.05). No statistically significant differences were found among DPSA, DPA, APSA, APA, and the control group. The aged PSA and PA achieved low bonding values and were statistically different from the control group, whereas the non-aged PSA and PA presented no statistically significant difference from the control group. Repairs with the proposed surface treatments were viable on both recent and aged restorations; however, phosphoric acid + adhesive alone were effective only on recent restorations.

Avaliação do comportamento mecânico de modelos odontológicos obtidos em resina de poliuretano / Evaluation of the mechanical behavior of odontological models in polyurethane resin

Este estudo avaliou o comportamento mecânico de uma resina de poliuretano Quartz-die (Zermack - Itália) empregada na modelagem odontológica comparando-a com o gesso tipo IV Durone (Dentsply - Brasil). Uma matriz metálica moldada com silicona de condensação Speedex (Coltène - Suiça) proporcionou corpos de prova com 12mm de altura por 6mm de diâmetro. Oito corpos de prova em resina de poliuretano e oito em gesso tipo IV (Durone) foram submetidos a ensaio de compressão na máquina de ensaios universal EMIC DL 2000, com célula de carga de 2000Kgf e velocidade de 0,05mm/min. Oito corpos de prova em resina de poliuretano e oito em gesso tipo IV obtidos a partir de uma matriz metálica hexagonal foram ensaiados noDurômetro Sussen Wolpert tipo Testor HTl, empregando penetrador esférico de 12,7mm, estabelecendo valores para dureza Rockwell. Os valores obtidos foram submetidos ao teste não-paramétrico de Kruskall-Walliscom p<0,05. Dentro dos parâmetros adotados neste estudo pôde-se concluir que a resina de poliuretano Quartz-die apresentou menor resistência à compressão e menor dureza superficial que o gesso tipo IV Durone.

Fatigue limits for composite restorations with and without glass ionomer cement liners.

This laboratory study compared the flexural endurance limits of clinical combinations of dental composite with and without glass ionomer cement (GIC) liners. Using only composite (Filtek Z350), specimens (10 mm long x 2 mm wide x 2 mm thick) in the control group were produced. Two GICs (Vitremer and Vitrebond) were used with the composite to prepare the test groups. Flexural strength and flexural fatigue limit (FFL) tests were performed. The FFL was determined using the staircase method. Data were analyzed by one-way ANOVA and Tukey's test. There was a significant difference in flexural strength values between the composite-only specimens and those produced by composite and GIC (p < 0.05). No statistical difference was observed in the flexural strength values between composite with Vitremer and composite with Vitrebond (p < 0.05). No statistically significant differences were detected in FFL values between composite with Vitremer and composite with Vitrebond; in addition, the mean value of the composite-only specimens differed statistically from those of both composite with Vitremer and composite with Vitrebond (p < 0.05). The FFL was lower than the flexural strength, indicating a decrease in flexural strength of 45 to 50%. Using GICs with composite decreased the mechanical properties (FFL and flexural strength) of the composite.

Effect of artificial accelerated aging on Vickers microhardness of composite resins.

Successful restoration depends on the mechanical resistance of dental restorative materials. The occlusal forces from masticatory contacts can affect the durability of restorations and cause fractures. Over time, monomers convert to polymers, leading to degradation of the organic matrix, which can interfere with mechanical resistance. This study sought to assess the effect of artificially accelerated aging on the microhardness of five composite resins: Filtek Z250, Charisma, Durafill VS, Filtek Supreme for body, and Filtek Supreme translucent. Ten test specimens were made of each material, using a 6.0 x 2.0 mm teflon matrix. After 24 hours, five test specimens of each material were submitted to the Vickers microhardness test (control group) for 10 seconds at a load of 300 kgf. The other five test specimens remained in the artificially accelerated aging machine for 196 hours and were submitted to the Vickers microhardness test. Filtek Z250 had the highest values and Durafill the lowest, both at 24 hours and after artificially accelerated aging. Artificially accelerated aging increased the microhardness of the composite resins.

Shear strength evaluation of composite-composite resin associations.

OBJECTIVE: The aim of this study was to investigate the shear strength between distinct associations of different commercial composite resins and their fracture modes. METHODS: Nine composite-composite associations (n=90) were prepared for shear strength evaluation and separated into the following groups: Z/Z (Filtek Z250 UD+Filtek Z250 A2); Z/D (Filtek Z250 UD+Durafill VS A2); Z/S (Filtek Z250 UD+Filtek Supreme YT); C/C (Charisma OA2+Charisma A2); C/D (Charisma OA2+Durafill VS A2); C/S (Charisma OA2+Filtek Supreme YT); H/H (Herculite XRV B2D+Herculite XRV B2E); H/D (Herculite XRV B2D+Durafill VS A2); H/S (Herculite XRV B2D+Filtek Supreme YT). Shear tests were carried out using universal mechanical test equipment with a load of 200kgf and speed of 0.5mm/min. Ultimate shear strength data (MPa) from all tested groups were submitted to analysis of variance (one-way ANOVA) and the Tukey test. The fractured surfaces of the test samples were visually evaluated by binocular stereomicroscope at 20 times magnification. Fractures were classified as either adhesive or cohesive or mixed. RESULTS: The highest ultimate shear strength observed for composite-composite associations was found for the groups: Z/Z, C/S, H/H, H/S, Z/S and C/C. Those associations containing the Durafill resin were weaker than the others. CONCLUSION: Microparticle RBC associations presented lower shear strength than hybrid and/or nanoparticle RBC associations, once the only significant difference was found when the Durafill resin was involved.

Study of dentinal adhesives compatibility using histological analysis

The objective of this study was to verify the biocompatibility of three different dental adhesives (Single Bond, Clearfil SE Bond and Prime & Bond NT). Thirty-six male rats (Rattus norvegicus, Holtzman) received two subcutaneous implants in the region of their backs. Artificial sponges containing the adhesive material were placed in the cavities and they were polymerized before the surgical site was sutured. As a control, one group was implanted with sponges containing water. Each rat received two implants containing the same adhesive; consequently each group consisted of 9 rats with two implants, resulting in 18 samples per group. After 7, 15 and 30 days, 3 animals of each group were killed and the tissues containing the sponges were analyzed by microscopy. The results showed a great similarity between the control group and the Single Bond implanted tissues, followed by the Clearfil SE Bond and Prime & Bond NT. The Prime & Bond NT adhesive system appeared to show less biocompatibility when compared with the other two tested materials.

Impact fracture strength applied to dental modeling materials

The aim of the present study was to analyze the impact fracture strength using plaster and resin modeling materials. The analysis was made using nine dies having plaster III bases and internal portion of laboratory-type addition silicone. Nine test specimens were produced of each following material: typeIV Durone plaster, type IV Fuji Rock plaster, type IV Rock Plus plaster, type V Durone plaster, Epoxiglass 1504 epoxy resin, epoxy resin modified with diatomite and epoxy resin modified with diatomite. The tests were performed in a Ceast testing machine. At the moment of fracture, the machine recorded avalue (Energy), using a formula to obtain the impact strength value in joules per meter. Statistical and variance analyses and Student's t test revealed that pure or silanized diatomite increased the impact fracture strength of models made of Epoxiglass 1504 epoxy resin and that silanizing the filler led toa further gain in impact fracture strength. The models made of Epoxiglass 1504 displayed greater impact fracture strength than those made of plaster types IV and V. No statistically significant differences were found among the analyzed plasters. Models prepared with epoxy resin displayed in general greater impact fracture strength than models made of plasters.

Rugosidade de diferentes tipos de gesso e dois tipos de resina epóxica utilizados como materiais de vazamento e análise da compatibilidade das resinas com materisis de moldagem / Roughness of dental stones and epoxy resin die materials and compatibility of the epoxy resins with impression materials

Este estudo avaliou a rugosidade superficial dos gessos Tipo IV e V e de uma resina epóxica pura e uma carregada com zirconita. Para a análise da rugosidade, os polímeros e os gessos foram vertidos em matrizes hexagonais apoiadas em lâmina de vidro, permitindo, após endurecimento dos materiais, três leituras em cada corpo-de-prova. Este estudo também avaliou a compatibilidade do polímero puro e da resina carregada com zirconita quando em contato com materiais elastoméricos utilizando dois critérios: aderência do molde e alteração na coloração do modelo. Para a análise da compatibilidade, os polímeros foram colocados em contato com quatro diferentes elastômeros e, após endurecimento dos materiais, realizou-se a inspeção com lupa de quatro aumentos. A resina foi 100% compatível com os materiais de moldagem. Com análise de variância e teste Tukey com significância 5%, verificou-se que não há diferença entre o gesso IV e o gesso V e que não há diferença entre a resina epóxica pura e a modificada com zirconita. Na comparação entre gessos e resinas, verificou-se que há diferença estatisticamente significante. Concluiu-se que: a adição de zirconita na proporção de 1/1 em peso na resina epóxica Epoxiglass 1504 e no endurecedor Epoxiglass 1603 proporcionou um material resinoso para obtenção de modelos compatível com os elastômeros mercaptana, poliéter, silicona de condensação e de adição; quando comparada aos gessos tipos IV e V, a resina epóxica Epoxiglass 1504 possibilitou obtenção de modelos com superior lisura superficial; a adição de zirconita na proporção de 1/1 na resina epóxica não comprometeu sua lisura superficial.

This study evaluated the surface roughness of Type IV and V dental plasters and epoxy resin with and without zirconite filler. To analyze the roughness, the polymers and plasters were poured into hexagonal dies supported on a sheet of glass, allowing, after hardening of the materials, for three readings of each test specimen. An evaluation was also made of the compatibility of this polymer, with and without zirconite filler, when in contact with elastomeric materials, based on two criteria: adherence of the die and alteration in the color of the model. To analyze the compatibility, the polymers were put into contact with four different elastomers and, after the materials hardened, they were examined with a magnifying glass with four times magnification. The resin was found to be 100% compatible with the molding materials. A variance analysis and Tukey’s test with 5% significance indicated that there was no difference between the IV and the V plasters, and that there was no difference between the pure epoxy resin and resin modified with zirconite. A comparison between plasters and resins revealed a statistically significant difference. It was concluded that the addition of zirconite in a 1:1 wt ratio to Epoxyglass 1504 resin and to Epoxyglass 1603 hardener produced a resinous material suitable for producing models compatible with the elastomers mercaptan, polyether, condensation silicone and silicone additive. When compared with the IV and V type plasters, the resinous epoxy Epoxyglass 1504 produced models with superior surface smoothness. The addition of zirconite in a proportion of 1:1 to epoxy resin did not affect the surface smoothness.

Entrenamiento de postura en pacientes portadores de disfunciones temporo-mandibulares / Posture training in patients with temporomandibular joint dysfunction

El objetivo de este trabajo fue el de realizar una revisión de literatura con el fin de identificar las alteraciones de posturales consecuentes de la Disfunción Temporomandibular y el tratamiento fisioterapéutico con entrenamiento postural. La metodología empleada fue una revisión bibliográfica por intermedio del sistema Medline y Lilacs, entre los años de 1993 y 2003, además de otros artículos y textos considerados importantes para este trabajo. Después de la lectura crítica fueron identificados dos temas: Las Disfunciones Temporomandibulares y su relación con la postura; las Disfunciones Temporomandibulares y el tratamiento fisioterapéutico por ejercicios y entrenamiento de postura. Conclusión: las alteraciones posturales pueden estar relacionadas a la Disfunción Temporomandibular y el uso de tratamiento fisioterapéutico con entrenamiento postural puede obtener resultados positivos.

O objetivo deste trabalho foi realizar uma revisão da literatura a fim de se obter um levantamento sobre quais alterações posturais sao decorrentes da Disfunção Temporomadibular e sua correlação com o tratamento fisioterapêutico e treino de postura. A metodologia empregada foi um levantamento bibliográfico realizado pelo sistema Medline e Lilacs, entre 1993 e 2003, além de outros artigos e textos considerados importantes para este trabalho. Após leitura crítica foram identificados dois temas: As Disfunções Temporomandibulares e sua relação com a postura; as Disfunções Temporomandibulares e o tratamento fisioterapêutico por exercícios e treino de postura. Conclusão: as alterações posturais podem estar relacionadas à Disfunção Temporomandibular, e o tratamento fisioterapêutico com treino de postura pode-se obter resultados positivos.

The aim of this work is to present survey on posture alterations due to Temporomandibular Joint Dysfunction and the related Physiotherapy treatment using posture training. The employed methodology was based on a large survey from 1993 to 2003 over well known datbases like Medline and Lilacs. Two main issues are present in almost all articles: how Dysfunction Temporomandibular Joint and posture are related and the Dysfunction Temporomandibular Joint treatment using training and exercises. The was observed that physiotherapy treatment using training and exercises was help patients to decrease the symptoms and, as a consequence, their posture.

Uso de una resina compuesta submicrohíbrida en dientes posteriores: relato de un caso clínico / The use of a microhybrid composite resin in posterior teeth: report of a clinical case

El presente trabajo relata la solución de un caso clínico en el cual fue utilizada una resina compuesta submicrohíbrida; con el objetivo de devolver no solo la función sino también la estética, por medio de la técnica restauradora directa. Después de realizados el examen clínico y radiográfico, se observo que las cúspides linguales y la restauración del diente 36 estaban fracturadas. Inicialmente fueron verificados los contactos oclusales así como el registro del color, que fue A3, de acuerdo con la escala Vita. El sistema adhesivo seleccionado fue Excite, asociado a la resina compuesta InTen-S, además de los pigmentos Tetric color. Se puede concluir que el uso de resina compuesta de bajo escurrimiento demostró buenos resultados clínicos.

The present study report a case which was used sub-microhibrid composite resin as aim to get better function and esthetic by a restorative protocol. At the clinical trial and x - ray, it was observed a deficient restoration allied with lingual cusp crack. The initial color was evaluated as A3, according by the Vita shade guide. The adhesion system used was Excite, restorative composite In Ten-S and Tetric color stain. It was conclude that this composite provide a healthier clinical aspects due to its proprieties.

Resistencia compresiva y traccional exhibida por un polímero alternativo utilizado en modelos odontológicos / Compressive and tensile resistance by an alternative polymer used in dental models

Este estudio pretendió evaluar el comportamiento de resistencia a la tensión de modelos odontológicos obtenidos a partir de una resina epóxica de uso industrial modificada con circonita. A la resina Epoxiglass 1504 y el endurecedor Epoxiglass 1603 les fue adicionada circonita en una proporción de 1 para 1 en peso; modificada de esta manera fue manipulada siguiendo las instrucciones del fabricante, el cual establece una proporción de 35 por ciento en peso entre la resina y el endurecedor. Fueron realizadas 15 impresiones de un modelo matriz, utilizando silicona de adición, siendo vaciados con Epoxiglass 1504, Epoxiglass 1504 modificada y Yeso Piedra tipo IV, obteniéndose 60 cuerpos de prueba en total. Las características de los mismos fueron: 12 mm. de altura y 6.0 mm. de diámetro. Los cuerpos de prueba fueron divididos en dos grupos de 30 cada uno, de estos uno de ellos fue sometido al ensayo mecánico de compresión y el otro al de tracción por compresión diametral, utilizando una máquina universal de ensayos DL2000 EMIC, con una célula de carga de 2000kgf y velocidad de 0,5mm/min. Los resultados fueron analizados con el análisis estadístico ANOVA y comprobación con el test de Tuckey con grado de exactitud de 5 por ciento verificando que: los modelos de resina epóxica Epoxiglass 1504 mostraron resistencia a compresión y resistencia a tracción por compresión diametral superior a los modelos de yeso tipo IV; la circonita aumenta la resistencia a tracción por compresión diametral de la resina Epoxiglass 1504. Frente a estos resultados, se puede concluir que la resina epoxica Epoxiglass 1504 se presenta como un material viable para la obtención de modelos odontológicos, así como también, que la circonita mejoró comportamiento mecánico del material en relación a las propiedades mecánicas estudiadas.

This study evaluated the tensil behavior of dental models obtained using an industrial epoxic resin modified with zirconita. The Epoxiglass resin 1504 and the hardener Epoxiglass 1603 were added with zirconita in a ratio of 1/1 in weight. The modified resin was manipulated in accordance with the manufacturer's specifications, which establishes a relation of 35% in weight between the resin and the hardener. Fifteen moldings of a matrix were conducted using addition silicone. Then, they were filled with epoxic resin Epoxiglass 1504, resin Epoxiglass 1504 modified or type IV Durone plaster, which provided 60 test specimens with 12mm of height and 6mm of diameter. Thirty specimens were submitted to the compression assay and thirty to the traction assay by diametrical compression, using the universal machine DL2000 (EMIC), with a load cell of 2000 Kgf and 0,5mm/mim speed. The results were analyzed by Variance analysis followed by Tukey test with significance level set at 5%. It was verified that models made of Epoxiglass 1504 presented superior tensile strenght for diametrical compression and also superior compressive strength than models made of plaster type IV. The zirconita increased the tensile strenght for diametrical compression of the epoxic resin Epoxiglass 1504. In accordance to the present results, it was verified that the epoxic resin Epoxiglass 1504 is a viable material for dental modeling and that the zirconita provides mechanical benefit for the epoxic resin.

Esse estudo avaliou o comportamento tensil de modelos odontológicos obtidos a partir de uma resina epóxica de uso industrial modificada com zirconita. A resina Epoxiglass 1504 e o endurecedor Epoxiglass 1603 foram carregados com zirconita numa proporção de 1/1 em peso. A resina modificada foi manipulada de acordo com as especificações do fabricante, que estabelece uma relação de 35% em peso entre a resina e o endurecedor. Foram realizadas quinze moldagens de uma matriz, os moldes foram obtidos com silicone de adição e preenchidos com resina epóxica Epoxiglass 1504, resina Epoxiglass 1504 modificada e gesso tipo IV Durone, o que proporcionou 60 corpos de prova com 12mm de altura e 6mm de diâmetro. Trinta corpos de prova foram submetidos ao ensaio de compressão e trinta ao ensaio de tração por compressão diametral, empregando-se a máquina universal de ensaios DL2000 da EMIC, com célula de carga de 2000Kgf e velocidade de 0,5mm/mim. Os resultados foram analisados com Teste de Variância e Tukey com significância de 5%, e verificou-se que: Modelos obtidos em resina epóxica Epoxiglass 1504 apresentam superior resistência à tração por compressão diametral que modelos obtidos em gesso tipo IV; Modelos obtidos em resina epóxica Epoxiglass 1504 apresentam superior resistência à compressão que modelos obtidos em gesso tipo IV; A zirconita aumenta a resistência à tração por compressão diametral da resina epóxica Epoxiglass 1504. Diante dos resultados encontrados, verificou-se que a resina epóxica Epoxiglass 1504 apresenta-se como material viável para a modelagem odontológica e que a zirconita proporciona ganho mecânico para a resina epóxica.

Influencia de las unidades de curado LED y luz halógena sobre la resistencia compresiva de las resinas compuestas / The influence of LED and halogen curing units on the compressive resistance of composite resins

El objetivo de este trabajo fue el de comparar la resistencia a compresión de tres diferentes marcas de resinas compuestas. Filtek Supreme (3M-ESPE), Charisma (Heraus-Kulzer), y Teric Ceram (Ivoclar-Vivadent), utilizando dos fuentes de fotopolimerización (Optilght,Gnathus y Ultraled (Dabi Atlante). En total fueron confeccionados 48 especímenes divididos en 6 grupos conteniendo 8 muestras cada uno. Para los grupos G1 (Filtek Supreme); G3 (Tetric Ceram) e G5 (Charisma) fue utilizada una lámpara de luz halógena; para los grupos G2 (Filtek Supreme); G4 (Tetric Ceram) e G6 (Charisma) fue utilizada una unidad de fotopolimerización por LEDs. El tiempo de polimerización fue el mismo recomendado por los propios fabricantes. Todas las muestras fueron almacenadas en recipientes plásticos negros herméticamente tapados durante 24 horas. Los ensayos mecánicos de compresión fueron realizados usando una Maquina Universal de Ensayos EMIC DL 2000, con célula de carga de 2000kgf con velocidad de acción de 0,5mm/minuto hasta producir la fractura. Los datos obtenidos fueron analizados usando los tests estadísticos ANOVA/Tukey (p<0,005). Las medias encontradas en MPa fueron: G1 248.37; G 2193.75; G3 222.00; G4 195.87; G5 280.37; G6 205.25. Se observó que las resinas compuestas Filtek Supreme y Charisma polimerizadas por luz halógena presentaron los valores de resistencia a compresión estadísticamente superiores a los mostrados por los grupos polimerizados con LEDs. El grupo de Tetric Ceram no mostró diferencia estadísticamente significante. El grupo 5 mostró valores superiores en relación a los otros grupos, siendo estadísticamente diferente de los grupos 2,3,4,6. El grupo 2 mostró los menores valores, siendo estadísticamente diferente de los grupos 1 y 5. Por los resultados obtenidos puede concluirse de que las resinas fotopolimerizadas por luz halógena presentaron los mejores resultados de resistencia a compresión con excepción de la resina compuesta Tetric Ceram.

This study main purpose was to evaluate the mechanical response of three different resin composite brands; Filtek Supreme, Charisma and Tetric Ceram cured by halogen or light emitting diode - LED (Optilght,Gnathus e Ultraled, Dabi Atlante). A nylon mold 4-mm in diameter and 8-mm in depth was used to obtain forty eight specimens dived in 6 groups of 8 varying the light-curing unit; G1 Filtek Supreme, G3 Tetric, G5 Charisma cured by halogen light-curing unit, and G2 Filtek Supreme, G4 Tetric, G6 Charisma cured by LED. The resin composites were inserted according to the incremental method. The resin composites were light cured according to the manufactures' instructions. The specimens were kept in plastic containers airtightly closed for 24 hours. In order to perform the evaluation, an EMIC DL 2000 was used at a crosshead speed of 0.5 mm/minute and a charge cell of 2000 Kg strength. The statistical analysis was performed using one-way analysis of variance (ANOVA) and Tukey test at a p<0.05 significance level. The mean were G1 248.37, G2 193.75, G3 222.00, G4 195.87, G5 280.37, G6 205.25. In conclusion, the resin composites light-cured by halogen scored higher in the compressive strength test. In the Tetric Ceram group there were no statistically relevant results.

Análise da fragilidade do Core- quando reconstruído com diferentes resinas e pinos pré-fabricados não metálicos / Analysis of the Core frailty whenever reconstructed with different composites resins and prefabricated no-metallic

Para realização deste estudo vinte condutos artificiais foram construídos em blocos formados por esmaltee dentina, a partir de dentes bovinos. Dez pinos de fibra de vidro e dez de fibra de carbono foram cimentadosnos condutos com cimento resinoso C&B. Empregou-se matriz de policarbonato para confecção do coreem resina composta, perfazendo quatro grupos: Grupo (1) pino de fibra de vidro e core com resina compostaCharisma; Grupo (2) pino de fibra de carbono e core com resina composta Charisma; Grupo (3) pino defibra de vidro e core com resina composta reforçada Enforce-core; Grupo (4) pino de fibra de carbono ecore com resina composta reforçada Enforce-core. Os ensaios mecânicos de compressão foram realizadosna máquina universal de ensaios EMIC DL 2000, com célula de carga 2000kgf e velocidade 1mm/mim.Verificou-se diferença estatística (p<0,05) (ANOVA) somente do fator resina no que tange as medidas daresistência à fratura do core, além disso, não há uma influencia significativa do tipo de fibra e nem mesmoda interação entre os fatores (resina x fibra). A conclusão para um fator é a mesma independentemente donível do outro fator. Os resultados para os dentes com resina composta reforçada diferem significativamentedos dentes que utilizaram resina composta não reforçada, onde, os dentes com resina composta reforçadaapresentaram medidas de resistência significativamente superiores aos dentes que utilizaram resina compostanão reforçada, independentemente do tipo de fibra (Teste de DUNCAN). Portanto, a fibra não influencia noresultado de resistência.