Evaluation of the color stability of light cured composite resins according to the resin matrices / 대한치과재료학회지

The purpose of this study was to evaluate the color stability of light cured composite resins according to the resin matrices. Three kinds of resin matrices such as Bis-GMA (Venus® Diamond; VD), Silorane (FiltekTM P90; P90), and Ormocer (Admira; Ad) were selected. Each of them were used to prepare 30 specimens. The initial CIE L*a*b* values were measured by means of a Spectrophotometer (NF999, Nippon Denshoku, Japan). For accelerated aging process, the specimens were immersed in a circulating water bath with distilled water at 60℃. Spectrophotometric analyses were made after immersion of 8, 16, 24, 41 days and the color difference (ΔE*) was calculated. The L* value increased compared with initial L* value. VD had the greatest L* value change and Ad had the smallest L* value change (p<0.05). Ad had the greatest a* value change and VD had the smallest a* value change (p<0.05). The b* value of P90 increased steadily in positive value (+)(p<0.05). ΔE* of Ad had the smallest value and that of P90 had the greatest change with time. According to this study, the value of light cured composite resins was increased with water sorption and color of those changed into greenish and yellowish. And according to the evaluation of color stability, Ad with Ormocer as resin matrices had the best color stability with time in oral environment and P90 with Silorane as resin matrices had the lowest color stability with time. And VD had the greatest initial ΔE*.

Effect of different clinical applications on physico-mechanical properties of composite resins / Efeito de diferentes aplicações clínicas nas propriedades físico-mecânicas de resinas compostas

Although clinicians use fluoride agents to reduce the occurrence of caries, and surface sealing agents to protect composite restorations, the effects of these agents on composite resins have not yet been investigated. The goal of this study was to determine the effect of different surface applications (fluoride or surface sealant) on resin composites with different organic structures (Siloranes, Sonicfill, 3M Z550, Kalore). In this study, 120 discs and 120 bars made of composite resin were stored in water for three months before being thermally aged by cycling between 5°C and 55°C for 10,000 cycles. The discs were 15 mm in diameter and 1 mm thick; the bars were 25 × 2 × 2 mm. The surface sealant and fluoride were applied to the specimens, and evaluations were performed after 24h. Initial and final calculations were performed for flexural strength, microhardness, roughness, gloss, water sorption, and solubility. Silorane composite showed the lowest water sorption levels (p < 0.05) for both initial and aged groups. Silorane and SonicFill composite groups showed the lowest solubility (p < 0.05). Both before and after aging, the SonicFill group showed the highest values of flexural strength and microhardness. Silorane showed the highest roughness and lowest gloss values. Lower water sorption and solubility rates were seen on materials fabricated from hydrophobic monomers. High water sorption and solubility degrades the mechanical and surface properties. Fluoridation and surface sealant application can alter the surface properties but do not have any effect on the mechanical properties.

Embora os clínicos utilizem agentes de flúor para reduzir a ocorrência de cáries e agentes de vedação de superfície para proteger restaurações compostas, os efeitos desses agentes sobre as resinas compostas ainda não foram investigados. O objetivo deste estudo foi determinar o efeito de diferentes aplicações de superfície (fluoreto ou selante de superfície) em resinas compostas com diferentes estruturas orgânicas (Siloranes, Sonicfill, 3M Z550, Kalore). Neste estudo, 120 discos e 120 barras de resina composta foram armazenados em água por três meses antes de serem envelhecidos termicamente por ciclos alternados entre 5 °C e 55 °C por 10.000 ciclos. Os discos tinham 15 mm de diâmetro e 1 mm de espessura; as barras eram 25 × 2 × 2 mm. O selante de superfície e o flúor foram aplicados nos espécimes e as avaliações foram realizadas após 24 horas. Cálculos iniciais e finais foram realizados para resistência à flexão, microdureza, rugosidade, brilho, sorção de água e solubilidade. O compósito de silorano apresentou os menores níveis de sorção de água (p <0,05) para os grupos inicial e envelhecido. Os grupos compostos Silorane e SonicFill apresentaram a menor solubilidade (p <0,05). Tanto antes quanto depois do envelhecimento, o grupo SonicFill apresentou os maiores valores de resistência à flexão e microdureza. Silorane apresentou a maior rugosidade e menores valores de brilho. Baixas taxas de sorção e solubilidade da água foram observadas em materiais fabricados a partir de monômeros hidrofóbicos. A alta sorção e solubilidade da água degrada as propriedades mecânicas e de superfície. A fluoretação e a aplicação de selante de superfície podem alterar as propriedades da superfície, mas não afetam as propriedades mecânicas.

Influence of enamel acid-etching on mechanical properties and nanoleakage of resin composite after aging

The aim of this study was to evaluate how acid-etching of the cavosurface enamel in Class I resin composite restorations influences the bond strength to the pulpal wall and the restoration, Knoop microhardness and nanoleakage after thermomechanical aging. For this research 76 fresh human molars were selected and restored with Silorane or Clearfil SEBond/Z350XT composite divided in 4 groups (Silorane system restored with or without enamel cavosurface acid-etching and Clearfil SEBond/Z350XT with or without enamel cavosurface acid-etching). To induce artificial aging, samples were subjected to thermomechanical cycling through 200,000 and thermal cycling between 5 and 55 °C with 30 second filling and 15-second drainage steps. Microhardness and microtensile bond strength were evaluated in 32 teeth (n=8) each and nanoleakage evaluation was performed in 12 teeth (n=3). Samples restored by Clearfil SEBond/Z350 XT without cavosurface acid-etching showed significantly lower microtensile bond strength results. The resin composite Z350XT presented higher values of Knoop microhardness. It was observed little or no infiltration for Silorane groups and moderate infiltration for Clearfil SE Bond groups. Acid-etching of the cavosurface enamel during restoration procedure with Clearfil Se Bond resulted in a stronger bond after thermomechanical cycling. Silorane groups showed less infiltration than Clearfil SE Bond groups (AU)

Thermal-induced polymerization shrinkage in silorane versus methacrylate based resin composite / Contração de polimeração induzida termicamenteem resinas compostas a base de silorano e metacrilato

Shrinkage is a limitation of resin composite, compromising the clinical longevity of the restorative procedure. In an attempt to reduce their harmful effects, researchers have studied monomers with lower values of contraction. As a result, low-shrinkage composites were developed. This study evaluated quantitatively the shrinkage as a function of power density increase based on methacrylates, comparing them with silorane based resin, and qualitatively regarding gap formation between the adhesive interface as function of tooth substrate. Resin Filtek P90 and Filtek Z250 were polymerized with the device Blue Star 3 with 200, 400, 600, 800 and 1000 mW/cm2 keeping volume constant in 12 mm3. For qualitative analysis of restorative interface, class V cavity preparations in bovine incisors were restored in (2x2x2 mm3), photoactivated with the same values of irradiance, and analyzed by scanning electron microscopy at the interface of the wall surrounding enamel, dentin and axial. The quantitative results of the polymerization shrinkage were analyzed by two-way ANOVA and Tukey's test (p<0.05), while qualitative data were submitedd to Mann-Whitney's, Kruskal-Wallis' and Miller's tests. The progressive increase in power density directly influenced the polymerization shrinkage of the materials studied, although the silorane based resin demonstrated significantly lower values. The marginal integrity was influenced by the dental substrate and the power density used.

Este estudo avaliou quantitativamente a contração de polimerização em função do aumento dos valores de densidade de potência irradiados em compósitos à base de metacrilatos e silorano, e qualitativamente a interface restauradora em relação à abertura de fendas marginais, em função da variação do tipo de substrato dentário. As resinas Filtek Z250 e Filtek P90 foram fotoativadas com 200, 400, 600, 800 e 1000 mW/cm2, em um volume constante de 12mm3, e os valores de contração foram aferidos por meio da máquina de ensaios universal. Para análise qualitativa da interface restauradora, preparos cavitários classe V de (2x2x2mm3) foram restaurados em incisivos bovinos, fotoativados com os mesmos valores de irradiância, e analisados em microscopia eletrônica de varredura nas interfaces da parede circundante em esmalte, parede circundante em dentina e parede axial. Os resultados quantitativos da contração de polimerização foram analisados pelo teste ANOVA a dois critérios e Tukey (p<0,05) enquanto para os dados qualitativos os testes Mann- Whitney, Kruskal-Wallis e Miller foram empregados. O aumento progressivo da densidade de potência influenciou diretamente na contração de polimerização dos materiais estudados, não obstante a resina composta à base de silorano ter demonstrado valores significativamente menores. A integridade marginal sofreu influência do substrato dentário bem como da densidade de potência utilizada, para as duas resinas estudadas.

Effect of water storage on flexural strength of silorane and methacrylate-based composite resins

OBJECTIVES: This study assessed the effect of water storage on the flexural strength (FS) of low shrinkage composites. MATERIALS AND METHODS: A total of 165 bar-shaped specimens (2 × 2 × 25 mm) were fabricated of 2 low shrinkage composites (Filtek P90 [3M ESPE], GC Kalore [GC International]) and a conventional methacrylate-based composite (Filtek Z250 [3M ESPE]). The specimens were subjected to 3-point bending test at 6 time intervals, namely: immediately after curing, at 24 hours, 1 week, 1 month, 6 months, and 1 year following storage in wet and dry conditions. The FS of the specimens were measured by applying compressive load at a crosshead speed of 1.0 mm/min. Data was analyzed using 3-way analysis of variance (ANOVA) and Tukey's test. RESULTS: Three-way ANOVA revealed significant interactions between time, type of composite, and storage condition (p = 0.001). Tukey's multiple comparison test revealed significant reductions in FS of all composites after 6 months and 1 year of storage in distilled water compared to dry condition. CONCLUSIONS: Filtek P90 showed the highest and GC Kalore showed the lowest FS after 1 year storage in distilled water. The immediate high strength of Filtek Z250 significantly decreased at 1 year and its final value was lower than that of Filtek P90.

Cytotoxicity and cytokine expression induced by silorane and methacrylate-based composite resins

ABSTRACT The successful use of composite resins in Dentistry depends on physicochemical properties, but also on the biological compatibility of resins, because of the close association between pulp and dentin. Objective The aim of this study was to evaluate cytotoxicity and cytokine production induced by light-cured or non-light-cured methacrylate-based and silorane composite resins in RAW 264.7 macrophages. Material and Methods Cells were stimulated with the extracts from light-cured or non-light-cured composite resins. After incubation for 24 h, cytotoxicity was assessed with the lactate dehydrogenase (LDH) and methyl thiazolyl tetrazolium (MTT) assays, and total protein was quantified using the Lowry method. TNF-α detection was examined with an enzyme-linked immunosorbent assay (ELISA) conducted with cell supernatants after cell stimulation for 6, 12, and 24 h. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test (α=0.05). Results KaloreTM and FiltekTM Silorane were cytotoxic with or without light curing (p<0.05) after 24 h of incubation. KaloreTM stimulated the early production of TNF-α in comparison with control (p<0.05), whereas FiltekTM Silorane did not affect TNF-α levels after 6 and 12 h (p>0.05). However, after 24 h FiltekTM Silorane inhibited the production of TNF-α (p<0.05). Conclusions KaloreTM and FiltekTM Silorane were cytotoxic regardless of light curing. The extract obtained from KaloreTM after 15 days of incubation stimulated the production of TNF-α, unlike that obtained from FiltekTM Silorane.

Repair Strength in Simulated Restorations of Methacrylate- or Silorane-Based Composite Resins

Abstract The study verified the bond strength in simulated dental restorations of silorane- or methacrylate-based composites repaired with methacrylate-based composite. Methacrylate- (P60) or silorane-based (P90) composites were used associated with adhesive (Adper Single Bond 2). Twenty-four hemi-hourglass-shaped samples were repaired with each composite (n=12). Samples were divided according to groups: G1= P60 + Adper Single Bond 2+ P60; G2= P60 + Adper Single Bond 2 + P60 + thermocycling; G3= P90 + Adper Single Bond 2 + P60; and G4= P90 + Adper Single Bond 2 + P60 + thermocycling. G1 and G3 were submitted to tensile test 24 h after repair procedure, and G2 and G4 after submitted to 5,000 thermocycles at 5 and 55 ?#61616;C for 30 s in each bath. Tensile bond strength test was accomplished in an universal testing machine at crosshead speed of 0.5 mm/min. Data (MPa) were analyzed by two-way ANOVA and Tukey's test (5%). Sample failure pattern (adhesive, cohesive in resin or mixed) was evaluated by stereomicroscope at 30?#61655; and images were obtained in SEM. Bond strength values of methacrylate-based composite samples repaired with methacrylate-based composite (G1 and G2) were greater than for silorane-based samples (G3 and G4). Thermocycling decreased the bond strength values for both composites. All groups showed predominance of adhesive failures and no cohesive failure in composite resin was observed. In conclusion, higher bond strength values were observed in methacrylate-based resin samples and greater percentage of adhesive failures in silorane-based resin samples, both composites repaired with methacrylate-based resin.

Resumo O objetivo neste estudo foi verificar a resistência de união em restaurações simuladas de compósitos baseados em metacrilato ou silorano reparadas com compósito à base de metacrilato. Compósitos baseados em metacrilato (Filtek P60; 3M ESPE) ou silorano (Filtek P90; 3M ESPE) foram associados com adesivo (Adper Single Bond 2; 3M ESPE). Vinte e quatro amostras em forma de semi-ampulhetas foram reparadas com cada material (n=12), conforme os grupos experimentais: G1- P60 + Adper Single Bond 2 + P60; G2- P60 + Adper Single Bond 2 + P60 + termociclagem; G3- P90 + Adper Single Bond 2 + P60; e G4- P90 + Adper Single Bond 2 + P60 + termociclagem. Os grupos G1 e G3 foram submetidos ao ensaio de tração após 24 horas do procedimento de reparo e os grupos G2 e G4 depois de submetidos a 5.000 ciclos térmicos de 5 e 55 ?#61616;C por 30 s em cada banho. O teste de resistência à tração foi efetuado em máquina universal atuando numa velocidade de 0,5 mm/min. Os dados (MPa) foram submetidos a ANOVA a dois fatores e teste de Tukey (5%). O padrão de fratura das amostras (adesivo, coesivo em resina ou misto) foi avaliado em estereomicroscópio com aumento de 30x e imagens representativas foram obtidas em MEV. Os valores de resistência à tração das amostras feitas com compósito à base de metacrilato e reparadas com compósito à base de metacrilato (G1 e G2) foram maiores do que nas amostras feitas com compósito à base de silorano e reparadas nas mesmas condições (G3 e G4). A termociclagem diminuiu os valores de resistência à tração para ambos os compósitos. Todos os grupos mostraram predominância de fraturas adesivas e nenhuma falha coesiva foi observada em compósito. Em conclusão, valores maiores de resistência à tração foram observados em amostras de resina à base de metacrilato e maior porcentagem de fraturas adesivas nas amostras de resina à base de silorano, ambos os compósitos reparados com resina à base de metacrilato.

Effect of filling technique on the bond strength of methacrylate and silorane-based composite restorations

Abstract The bond strength of methacrylate (Z350, 3M ESPE) and silorane (P90, 3M ESPE) restorations, using different cavity filling techniques, was investigated. Cavities (6 × 3 × 3) in bovine teeth were filled using bulk, oblique, or horizontal increments. A push-out test was carried out after 24 h. Data were statistically analyzed (α = 5%). Methacrylate-based composites and the horizontal filling technique showed the highest bond strength values (10.2 ± 3.9, p < 0.05). Silorane-based composites showed no statistically significant differences regarding the filling techniques (p > 0.05).

Influence of tooth bleaching on the bonding strength of silorane-based restorative system / Influencia del aclaramiento dental en la fuerza de adhesion del sistema restaurativo a base de silorano

Bleaching procedures can interfere on adhesive bonding of methacrylate-based restorative materials. After introduction of silorane-based composites, little information is available about this interaction. The objective is evaluate the influence of bleaching on enamel shear bond strength of silorane-based restorative system. Forty sound incisive bovine teeth were randomly divided into 04 groups (n= 10), being: G1 (control) ­ not bleached + Clearfil SE Bond (CSEB)/Filtek Z250 (Z250), G2 (control) not bleached + Silorane Adhesive (SA)/Filtek P90 (P90), G3 ­ bleached + CSEB/Z250; G4 ­ bleached + SA/P90. The teeth were sectioned, had crowns included in a PVC rings, and the enamel surfaces gridded and polished with silicon carbide abrasive papers. G1 and G2 were stored in artificial saliva (37 C), daily renewed, for a period of 04 days. G3 and G4 were exposed to 02 sessions of 38% hydrogen peroxide (38HP), with 03 applications of 15 min in each session. Composite resin cylinders were built up on the enamel surfaces. Bonding procedures were performed according the manufacturer's instructions. After storage in distilled water for 24 h (37 C), the samples were submitted to shear bond test. Data were analyzed by two-way ANOVA and t (LSD) tests (5%). Intra group comparison showed significant difference for Z250 after bleaching, but not for P90. Shear strength was significant lower for P90, despite bleaching procedures. In conclusion, 38HP bleaching had no influence on the enamel bond strength of P90, even though presenting lower bond strength than Z250.

Los procedimientos de blanqueamiento dental pueden interferir en la unión adhesiva de los materiales de restauración a base de metacrilato. Después de la introducción de materiales compuestos a base de silorano, hay poca información disponible acerca de esta interacción. El objetivo fue evaluar la influencia del blanqueamiento en la cizalladura de la fuerza de adhesion sobre esmalte del sistema restaurativo a base de silorano. Cuarenta dientes incisivos bovinos fueron divididos aleatoriamente en 4 grupos (n= 10), siendo: G1 (control) - no aclarado + Clearfil SE Bond (CSEB)/Filtek Z250 (z250), G2 (control) - no aclarado + adhesivo de silorane (AS)/Filtek P90 (P90), G3 - aclarado + CSEB / Z250; g4 - aclarado + AS/P90. Los dientes fueron seccionados, tenían coronas incluidas en anillos de pvc, y las superficies de esmalte fueron molidas y pulidas con papeles abrasivos de silicona de silicio. G1 y G2 fueron almacenados en saliva artificial (37 °C), renovada diariamente, durante un período de 04 días. G3 y G4 se expusieron a 2 sesiones de peróxido de hidrógeno al 38% (38 HP) con 03 aplicaciones de 15 min en cada sesión. Los cilindros de resina compuesta fueron construidos en las superficies de esmalte. Los procedimientos de unión se realizaron según las instrucciones del fabricante. Después del almacenamiento en agua destilada durante 24 h (37 °C), las muestras fueron sometidas al ensayo de resistencia de adhesión al cizallamiento. Los datos fueron analizados por ANOVA de dos vías y prueba t (5%). La comparación intragrupo mostró diferencias significativas para Z250 después del aclaramiento, pero no para P90. La resistencia al corte fue significativamente menor para P90, a pesar de los procedimientos de blanqueamiento. En conclusión, el blanqueamiento con 38HP no tuvo influencia en la resistencia de la unión esmalte de P90, a pesar de presentar una fuerza de unión más baja que Z250.

The contribution of distance learning to the knowledge of nursing lecturers regarding assessment of chronic wounds / Contribuição da educação a distância para o conhecimento de docentes de enfermagem sobre avaliação de feridas crônicas / Contribución de la educación a distancia para el conocimiento de docentes de enfermería sobre evaluación de heridas crónicas

OBJECTIVE: to identify the contribution made by a refresher course on the assessment of chronic wounds, offered through the Moodle virtual learning environment (VLE), to the knowledge relating to this issue of nursing lecturers and nurses linked to higher education. METHOD: a prospective, quasi-experimental study, with data collection before and after the educational intervention. The study was undertaken in three stages using the Moodle VLE. The sample was made up of 28 participants who answered the pre-test on the knowledge, devised in accordance with international guidelines on chronic wounds. Afterwards, the refresher course was offered (intervention) and was accessed in accordance with individuals' schedules, during the established time period. At the end of the course, 26 participants answered the post-test. Those who did not participate in the post-tests were excluded from the study, as it is pairwise analysis of the sample. RESULT: the participants obtained, on average, 55.5% of correct answers in the pre-test on their knowledge, and 73.4% in the post-test, this difference being statistically significant. There was a negative correlation between the time of experience in lecturing and the performance in the test on their knowledge. CONCLUSION: the participation in the online refresher course contributed to improving the lecturers' performance in the test on their knowledge, in relation to the recommendations for assessing chronic wounds, based in scientific evidence. .

OBJETIVO: identificar a contribuição de um curso de atualização sobre a avaliação de feridas crônicas, oferecido pelo Ambiente Virtual de Aprendizagem (AVA) Moodle, para o conhecimento de docentes de enfermagem e enfermeiros vinculados ao ensino superior, acerca da temática. MÉTODO: estudo prospectivo, quase-experimental, com coleta de dados antes e após intervenção educativa. O estudo foi desenvolvido em três etapas, através do AVA Moodle. A amostra foi composta por 28 participantes, que responderam ao pré-teste de conhecimento, elaborado de acordo com diretrizes internacionais sobre feridas crônicas. Após, o curso de atualização foi oferecido (intervenção) e acessado conforme programação individual, durante prazo estabelecido. Ao término do curso, 26 participantes responderam ao pós-teste. Aqueles que não participaram do pós-teste foram excluídos do estudo, por tratar-se da análise pareada da amostra. RESULTADO: os participantes obtiveram, em média, 55,5% de acertos no pré-teste de conhecimento, e 73,4%, no pós-teste, sendo essa diferença estatisticamente significante. Houve correlação negativa entre o tempo de experiência na docência e o desempenho no teste de conhecimento. CONCLUSÃO: a participação no curso de atualização on-line contribuiu para melhor desempenho dos docentes no teste de conhecimentos, sobre as recomendações para avaliação de feridas crônicas, com embasamento em evidência científicas. .

OBJETIVO: identificar la contribución de un curso de actualización sobre la evaluación de heridas crónicas, ofrecido por el ambiente virtual de aprendizaje (AVA) Moodle, para el conocimiento de docentes de enfermería y enfermeros vinculados a la enseñanza superior, acerca de la temática. MÉTODO: estudio prospectivo, casi experimental, con recolección de datos antes y después de la intervención educativa. El estudio fue desarrollado en tres etapas a través del AVA Moodle. La muestra fue compuesta por 28 participantes, que respondieron a la preprueba de conocimiento, elaborada de acuerdo con directrices internacionales sobre heridas crónicas. Después, el curso de actualización fue ofrecido (intervención) y accedido conforme programación individual, durante un plazo establecido. Al término del curso, 26 participantes respondieron a la postprueba. Aquellos que no participaron de la postprueba, fueron excluidos del estudio, por tratarse de un análisis pareado de la muestra. RESULTADOS: los participantes obtuvieron, en promedio, 55,5% de aciertos en la preprueba de conocimiento, y 73,4%, en la postprueba, siendo esa diferencia estadísticamente significativa. Hubo correlación negativa entre el tiempo de experiencia en la docencia y el desempeño en la prueba de conocimiento. CONCLUSIÓN: la participación en el curso de actualización on-line contribuyó para mejorar el desempeño de los docentes en la prueba de conocimientos sobre las recomendaciones para evaluación de heridas crónicas, con base en evidencia científicas. .

Effect of thermal cycling on the composite- composite repair bond strength / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of aging of the composite and the adhesive interface on composite-composite repair bond strength.</p><p><b>METHODS</b>Methacrylate-based composite resin (Clearfil AP-X, composite A) and silorane-based composite resin (Filtek P90, composite B) and their corresponding adhesive, Clearfil SE Bond (adhesive a) and Filtek P90 System Adhesive (adhesive b), were selected in this study. Twenty-four substrates were prepared from composite A or B separately and divided into three groups, each group had 8 substrates: group one, new composites were adhered to the substrates with the use of adhesive a or b, followed by cutting the blocks into sticks; group two, new composites were adhered to the substrates using adhesive a or b, followed by cutting into sticks and thermal cycling; group three, substrates were thermocycled, then polished and adhered new composites using adhesive a or b, followed by cutting into sticks. Each group had 8 combinations of substrate(A, B)-adhesive(a, b)-repair composite (A, B). Fifteen sticks without flaws in each combination of 3 groups were selected utilizing stereomicroscope. The data were analyzed by independent samples t test.</p><p><b>RESULTS</b>In group two, the microtensile strength(MS) of combinations using adhesive a and composite A or B to repair [A-a-A: (45.0 ± 3.2) MPa, B-a-A: (41.7 ± 3.3) MPa, A-a-B: (28.6 ± 3.9) MPa, B-a-B: (47.7 ± 6.6) MPa], and using adhesive b and composite A to repair [A-b-A: (44.2 ± 4.7) MPa, B-b-A: (38.0 ± 3.2) MPa] decreased significantly compared with corresponding combinations in group 1[A-a-A: (70.7 ± 5.5) MPa, B-a-A: (60.3 ± 5.1) MPa, A-a-B: (44.2 ± 1.6) MPa, B-a-B: (54.1 ± 3.2) MPa, A-b-A: (65.6 ± 7.2) MPa, B-b-A: (59.1 ± 4.1) MPa] (P<0.05). However, there was no significant difference between the MS of combinations using adhesive b and composite B to repair in group one and the MS of combinations in group two (P>0.05). The MS of all combinations in group three decreased significantly (P<0.05).</p><p><b>CONCLUSIONS</b>Aging of the composite and the adhesive interface might affect the composite-composite repair bond strength.</p>

Aging of silorane- and methacrylate-based composite resins: effects on color and translucency / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the color stability and translucency of silorane-based low shrinkage composite after in vitro aging procedures of thermal cycling and water storage respectively, and to compare with those of conventional methacrylate-based posterior composite.</p><p><b>METHODS</b>Three light-cured composite resins, dimethacrylate-based composite A (Filtek™ Z350), B (Filtek™ P60) and silorane-based composite C (Filtek™ P90), were tested in this study. Ten specimens (10 mm in diameter, 1 mm in height) of each composite were prepared. The ten specimens in each group were then divided into two subgroups (n = 5). One subgroup underwent thermal cycling [(5.0 ± 0.5)~(55.0 ± 1.0) °C, 10 000 cycles] and the other was stored in 37 C° distilled water for 180 days. With a spectrophotometer, the CIE L * a * b * parameters of the specimens were tested before and after artificial aging against white, medium grey and black backgrounds, respectively. △E, TP and △TP were calculated and data were analyzed using independent-samples t test and partial analysis (P < 0.05).</p><p><b>RESULTS</b>With regard to color stability, silorane-based composite showed color alteration above the clinically acceptable levels (△E > 3.3), and also showed higher △E with a statistically significant difference in comparison with the other composites (B and C) (P < 0.05) after artificial aging. With regard to translucency, composite C showed more alteration compared with composite B (P < 0.05) after thermal cycling.</p><p><b>CONCLUSIONS</b>It may be concluded that the silorane-based composite underwent greater alteration with regard to color stability and translucency.</p>

Microtensile bond strength of silorane-based composite specific adhesive system using different bonding strategies

OBJECTIVES: The aim of this study was to evaluate the effect of pre-etching on the bond strength of silorane-based composite specific adhesive system to dentin. MATERIALS AND METHODS: Thirty human molars were randomly divided into 5 groups according to the different bonding strategies. For teeth restored with silorane-based composite (Filtek Silorane, 3M ESPE), the specific self-etching adhesive system (Adhesive System P90, 3M ESPE) was used with and without pre-etching (Pre-etching/Silorane and Silorane groups). Teeth restored with methacrylate based-composite (Filtek Z250, 3M ESPE) were hybridized with the two-step self-etching system (Clearfil SE Bond, Kuraray), with and without pre-etching (Pre-etching/Methacrylate and Methacrylate groups), or three-step adhesive system (Adper Scotchbond Multi-Purpose, 3M ESPE) (Three-step/Methacrylate group) (n = 6). The restored teeth were sectioned into stick-shaped test specimens (1.0 x 1.0 mm), and coupled to a universal test machine (0.5 mm/min) to perform microtensile testing. RESULTS: Pre-etching/Methacrylate group presented the highest bond strength values, with significant difference from Silorane and Three-step/Methacrylate groups (p < 0.05). However, it was not significantly different from Preetching/Silorane and Methacrylate groups. CONCLUSIONS: Pre-etching increased bond strength of silorane-based composite specific adhesive system to dentin.

The effect of different drinks on the color stability of different restorative materials after one month

OBJECTIVES: The aim of this study was to evaluate the effect of three different drinks on the color parameters of four different restorative materials. MATERIALS AND METHODS: Three different composites (Filtek Ultimate Universal Restorative, Filtek Ultimate Flowable, and Filtek Silorane, 3M ESPE) and a polyacid-modified composite resin material (Dyract XP, Dentsply DeTrey GmbH) were evaluated. Eighty-four disc-shaped specimens of 8 mm in diameter and 2 mm in thickness were prepared (n = 21 each). Color coordinates (L*a*b*, DeltaL*, Deltaa*, Deltab*, and DeltaE*) were measured using a VITA Easyshade Compact (VITA Zahnfabrik) after 24 hr of storage (baseline) and after 30 day of storage in three different beverages of black tea, Coca cola, or water (control) (n = 7). In each beverage, the specimens were stored three times a day, one hr each, for 30 day. The color changes (DeltaE) were calculated and were analyzed by Kruskal-Wallis and Dunn multiple comparison test. RESULTS: The color difference (DeltaE*) of the resin materials ranged between 1.31 and 15.28 after 30 day of immersion in the staining solutions. Dyract XP in Coca cola (15.28 +/- 2.61) and black tea (12.22 +/- 2.73) showed the highest mean DeltaE* value after 30 day, followed by Filtek Ultimate Universal Restorative (5.99 +/- 1.25) and Filtek Ultimate Flowable (4.71 +/- 1.40) in black tea (p < 0.05). CONCLUSIONS: The compomers displayed unacceptable color changes at the end of 30 day in all beverages. Among resin composites, the silorane based composite exhibited relatively good color stability than the others. Filtek Ultimate Universal Restorative and Filtek Flowable showed similar color changes in all beverages.

Effect of pre- heating on hardness of methacrylate- and silorane- based composites

AIM: To evaluate the effect of composite pre-heating on the microhardness of different monomer resin-based. MATERIALS AND METHOD: Circular specimens of methacrylate- and silorane-based composite resins pre-heated at 23, 39, and 55˚ C were carried out, and cured using a halogen light-curing unit at 650 mW/cm². After 24 h, the specimens were polished and Knoop hardness number (KHN) was measured using a microhardness tester with 50-g load for 15 s. The data were analyzed with ANOVA and Tukey's tests (α = 0.05). RESULTS: Top surface presented higher KHN than bottom, methacrylate-based composite showed higher KHN compared to silorane, and pre-heating increased the KHN of the composites tested. CONCLUSION: Pre-heating can be used to improve the microhardness of methracrylate- and silorane-based composites.

Radiant exposure effects on physical properties of methacrylate - and silorane-composites

AIM: To evaluate the effect of different radiant exposures on the degree of conversion (DC), Knoop hardness number (KHN), plasticization (P), water sorption (WS), and solubility (S) of different monomer resin-based composites. METHODS: Circular specimens (5 x 2 mm) were manufactured from methacrylate and silorane composite resins, and light-cured at 19.8, 27.8, 39.6, and 55.6 J/cm2, using second-generation LED at 1,390 mW/cm2. After 24 h, DC was obtained using a FT-Raman spectrometer equipped with a Nd:YAG laser, KHN was measured with 50-g load for 15 s, and P was evaluated on the top and bottom surfaces by the percentage of hardness reduction after 24 h immersed in absolute alcohol. WS and S were determined according to ISO 4049. Data were subjected to statistical analysis (α=0.05). RESULTS: Methacrylate material presented higher DC, KHN, P, and WS than silorane (p<0.05). There was no difference in the S values (p>0.05). The increased radiant exposures improved only the KHN (p<0.05). In general, top surfaces showed higher DC and KHN than bottom, for both materials (p<0.05). The increase of the radiant exposure did not improve most physical properties of the composites and were monomer-base dependent. CONCLUSIONS: Chemical composition of the composite resins resulted in different physical properties behavior and could affect the clinical longevity of dental restorations, but overall these properties were not influenced by the different radiant exposures evaluated in the study...

Impact of light-curing time and aging on dentin bond strength of methacrylate- and silorane-based restorative systems

AIM: To evaluate the impact of different light-curing times on dentin microtensile bond strength of two restorative systems after 24 h and 6 months of water storage. METHODS: Standardized Class II preparations were performed in 56 freshly-extracted human molars (n = 7), restored with methacrylate- or silorane-based restorative systems, and light-cured using a light-emitting diode at 1390 mW/cm2 by the recommended manufacturers' time or double this time. After storage for 24 h at 37 oC, the teeth were sectioned to yield a series of 0.8-mm thick slices. Each slab was trimmed into an hourglass shape of approximately 0.64 mm2 area at the gingival dentin-resin interface. Specimens were tested using universal testing machine at crosshead speed of 0.5 mm/min until failure, after 24 h and 6 months of storage. Data were statistically analyzed by three-way ANOVA and Tukey's test (α = 0.05). RESULTS: The highest bond strength values were recorded for the groups restored with methacrylate system (p<0.001) as well as for extended light-curing time (p = 0.0034). There was no statistically significant difference between 24 h and 6 months storage on bond strength (p>0.05). CONCLUSIONS: Bond strength was influenced by the material and light-curing time, but the 6-month storage did not affect the bond strength of restorations...

Evaluation of shear bond strength of two resin-based composites and glass ionomer cement to pure tricalcium silicate-based cement (Biodentine®)

Objectives: Tricalcium silicate is the major constituent phase in mineral trioxide aggregate (MTA). It is thus postulated that pure tricalcium silicate can replace the Portland cement component of MTA. The aim of this study was to evaluate bond strength of methacrylate-based (MB) composites, silorane-based (SB) composites, and glass ionomer cement (GIC) to Biodentine® and mineral trioxide aggregate (MTA). Material and Methods: Acrylic blocks (n=90, 2 mm high, 5 mm diameter central hole) were prepared. In 45 of the samples, the holes were fully filled with Biodentine® and in the other 45 samples, the holes were fully filled with MTA. The Biodentine® and the MTA samples were randomly divided into 3 subgroups of 15 specimens each: Group-1: MB composite; Group-2: SB composite; and Group-3: GIC. For the shear bond strength (SBS) test, each block was secured in a universal testing machine. Results: The highest (17.7±6.2 MPa) and the lowest (5.8±3.2 MPa) bond strength values were recorded for the MB composite-Biodentine® and the GIC-MTA, respectively. Although the MB composite showed significantly higher bond strength to Biodentine (17.7±6.2) than it did to MTA (8.9±5.7) (p<0.001), the SB composite (SB and MTA=7.4±3.3; SB and Biodentine®=8.0±3,6) and GIC (GIC and MTA=5.8±3.2; GIC and Biodentine=6.7±2.6) showed similar bond strength performance with MTA compared with Biodentine (p=0.73 and p=0.38, respectively). Conclusions: The new pure tricalcium-based pulp capping, repair, and endodontic material showed higher shear bond scores compared to MTA when used with the MB composite. .

Desempenho clínico de um sistema de resina composta e adesivo à base de silorano em restaurações classe I: estudo controlado e randomizado / Clinical performance of a silorane-based composite-resin in class I restoration: randomized clinical study

O objetivo deste ensaio clínico foi comparar o desempenho de uma resina composta e sistema adesivo à base de silorano com um sistema à base de metacrilato, em restaurações classe I. Em modelo de boca dividida, 51 pacientes receberam pelo menos um par de restaurações, que foram alocados aleatoriamente em grupos teste (Filtek P90 e sistema adesivo silorano, 3MESPE) e controle (Filtek P60 e sistema adesivo Adper SE Plus, 3MESPE). Um único operador realizou as restaurações, seguindo os protocolos estabelecidos. Depois de uma semana, as restaurações foram polidas e avaliadas de forma cega e independente por dois examinadores, treinados e calibrados...

Fracture resistance of endodontically treated maxillary premolars restored by silorane-based composite with or without fiber or nano-ionomer

PURPOSE: This in vitro study investigated the fracture resistance of endodontically treated premolars restored using silorane- or methacrylate-based composite along with or without fiber or nano-ionomer base. MATERIALS AND METHODS: Ninety-six intact maxillary premolars were randomly divided into eight groups (n = 12). G1 (negative control) was the intact teeth. In Groups 2-8, root canal treatment with mesio-occlusodistal preparation was performed. G2 (positive control) was kept unrestored. The other groups were restored using composite resin as follows: G3, methacrylate-based composite (Z250); G4, methacrylate composite (Z250) with polyethylene fiber; G5 and G6, silorane-based composite (Filtek P90) without and with the fiber, respectively; G7 and G8, methacrylate- and silorane-based composite with nano-ionomer base, respectively. After aging period and thermocycling for 1000 cycles, fracture strength was tested and fracture patterns were inspected. The results were analyzed using ANOVA and Tukey HSD tests (alpha=0.05). RESULTS: Mean fracture resistance for the eight groups (in Newton) were G1: 1200 +/- 169a, G2: 360 +/- 93b, G3: 632 +/- 196c, G4: 692 +/- 195c, G5: 917 +/- 159d, G6: 1013 +/- 125ad, G7: 959 +/- 148d, G8: 947 +/- 105d (different superscript letters revealed significant difference among groups). Most of the fractures in all the groups were restorable, except Group 3. CONCLUSION: Silorane-based composite revealed significantly higher strength of the restored premolars compared to that of methacrylate one. Fiber insertion demonstrated no additional effect on the strength of both composite restorations; however, it increased the prevalence of restorable fracture of methacrylate-based composite restored teeth. Using nano-ionomer base under methacrylate-based composite had a positive effect on fracture resistance and pattern. Only fiber-reinforced silorane composite restoration resulted in a strength similar to that of the intact teeth.