Evaluation and comparison of silorane resin composite to glass ionomer in occluso-proximal restorations of primary molars A randomized controlled trial

Objective: In general, proximal restorations of primary molars fracture, so it is vital to study the new materials that could solve this problem. Hence, the present trial assessed the success of occluso-proximal atraumatic restorative treatment (ART) restorations using silorane and glass ionomer cement (GIC) in carious primary molars for a period of 2 years. Materials and Methods: One hundred and ninety-two children between the age group of 4 and 9 years were randomly allocated to GIC or silorane. In the clinical set up, they were treated by a pediatric dentist, and their restorations were evaluated at 3, 6, 12, 18, and 24 months. The primary outcome was the survival of restoration, which was analyzed using the Kaplan–Meier and superior Cox regression models. As a sensitivity analysis, intention-to-treat (ITT) was executed. Sex, age, molar, jaw, cavity volume, and caries incidence were the independent variables. Results: The restoration survival after 24 months for GIC and silorane was 82.75% and 88.88%, respectively, whereas ITT analysis showed a success of 84.37% and 89.58% for GIC and silorane, respectively. Conclusion: With regard to longevity, there was no statistically significant difference between silorane and GIC in primary molar occlusoproximal ART restorations.

Influence of Different Surface Treatments on the Bond Strength Between Composites and Resin Cement / INFLUÊNCIA DE DIFERENTES TRATAMENTOS DE SUPERFÍCIE NA RESISTÊNCIA DE UNIÃO ENTRE COMPÓSITOS E CIMENTO RESINOSO

The aim of this study was to evaluate the influence of different surface treatments on bond strength (BS) between composite and a resin cement trough microshear bond strength test. Seventy five discs (10x2 mm) of Filtek P90, Filtek Z250 and Filtek Z350 XT (3M ESPE), were divided into 5 groups according to the treatment: C= control - no treatment; sandblasting J= aluminum oxide (50µm); sandblasting JE = + 99.3% ethanol for 5 min; silica coating S = (3M-ESPE Cojet - 30 microns); SS = silica coating + silane. PVC tubes (0.5 x 0.80 mm) were attached on the composite disc, and then, inserted resin cement (3M ESPE-RelyX ARC). After 24 hours artificial saliva storage at 37oC, the specimens were tested for microshear crosshead speed of 1.0 mm/min. Data were evaluated in two-way ANOVA and Tukey's test (5%) for contrast. The results showed that sandblasting with aluminum oxide (J) was efficient in increasing the BS for composites Z350 and P90. For the Z250, there were no difference between treatments. Also, CS showed results similar to controls for all composites. SE showed the worst results for Z350 e P90. BS values were dependent on the type of composite and the surface treatment used. Sandblasting with aluminum oxide seems to be an effective surface treatment for composites and may lead to higher BS values, while the use of ethanol could be harmful.

O objetivo deste estudo foi avaliar a influência de tratamentos de superfície na resistência de união (RU) entre compósitos e um cimento resinoso. Setenta e cinco discos (10x2 mm) das resinas Filtek P90, Filtek Z250 e Filtek Z350 (3M ESPE) foram divididos em 5 grupos de acordo com o tratamento: N= sem tratamento; S= jateamento com óxido de alumínio (50µm); SE= jateamento de óxido de alumínio + 99,3% de etanol por 5 min; C= jateamento de sílica com Cojet - 30 microns (3M ESPE); CS= jateamento de sílica + silano. Tubos de PVC (0,5 x 0,80 mm) foram fixados nos discos e o cimento resinoso (RelyX ARC, 3M ESPE) foi inserido. Após 24 horas de armazenamento em saliva artificial a 37oC, os espécimes foram submetidos ao teste de microcisalhamento com velocidade de 1,0 mm/min. Os dados foram avaliados em ANOVA de dois fatores e no teste de Tukey (5%) para contraste. Os resultados mostraram que o tratamento com oxido de alumínio (J) foi eficiente no aumento da RU nos compósitos Filtek Z350 e P90. Não houve diferença entre tratamentos para a Z250. Grupo CS mostrou resultados semelhantes aos do controle para todos os compósitos. Já o SE mostrou os piores resultados de RU. Concluiu-se que os valores de RU foram dependentes do tipo de compósito e do tratamento de superfície utilizado. O jateamento com óxido de alumínio parece ser um tratamento de superfície eficaz e pode elevar os valores de RU, já o uso de etanol pode ser prejudicial

Microleakage in posterior teeth with different materials and different types of cavities

Background: The purpose of this study was to investigate the behavior of a resin-based 2,2-bis (p-[2′-hydroxy-3′-methacryloxypropoxy] phenylene) propane and a composite resin modified with oxirane, regarding the ability of marginal sealing, both with direct restorations and indirect restorations. Materials and Methods: To achieve this, mesio- and disto-occlusal cavities were made on the same tooth, totalling 100 cavities. These cavities were restored with two materials, Filtek P90 (3M ESPE) and Opallis (FGM). Then, they were divided into two groups: Fifty direct restorations, each sample restored with the two materials, following the manufacturer's protocol and fifty indirect restorations, and then cemented with a paste obtained by diluting the resin in its adhesive. The templates were thermally cycled, 30 s at 5°C and 30 s at 55°C for 500 cycles and then were immersed in methylene blue for 24 h. Afterward, they were trimmed using a plaster trimmer from occlusal toward a gingival direction. These samples were analyzed with stereomicroscope (×3) by two blinded observers. Then, a system which considers the average number of surrounding walls that have suffered infiltration on a scale of 0–3 was used. Results: Data were subjected to statistical analysis (Mann–Whitney and Kruskal–Wallis tests) with a significance level of 5% maximum. Conclusion: It was concluded that the indirect restorations showed the greatest number of restorations with score 0 and 1 (34) and lowest score 2 and 3 (16). This suggests that indirect restorations regardless of the material used behaved more effectively regarding the marginal sealing of restorations.

Evaluation of Finishing/Polishing Techniques on Low-Shrink Posterior Restorative After Mechanical Cycling / Avaliação de Técnicas de Acabamento/Polimento em Restaurações Posteriores de Baixa Contração Após Ciclagem Mecânica

The aim of this study was to evaluate the surface roughness of a silorane and methacrylate-based composite resins subjected to different finishing/polishing techniques. Twelve disk specimens were prepared from each composite resin: P90®, Z350® and Charisma, divided into 12 groups according to the finishing/polishing technique: no finishing/polishing (control); finishing with 1112 FF diamond burs; finishing with 1112 FF diamond burs associated to Enhance/Pogo; finishing with 1112 FF diamond burs associated to Enhance/Pogo/Polishing/Poli I and II pastes/Fotogloss. After initial readouts of surface roughness, the specimens were subjected to mechanical cycling (1.200.000 cycles) and immediately subjected to final roughness readouts. Surface roughness means was statistically analyzed by ANOVA and Tukey-Kramer test (α=0.05). SEM images were realized after finishing/polishing and after mechanical cycling. The P90 composite showed surface roughness values similar to other investigated composites. However, significant difference was observed in finishing/polishing techniques. The diamond burs group showed the highest surface roughness differing from the other composite resins (α < 0.05). Enance/Pogo showed the lowest results, which presented no difference compared to the polishing paste group (α > 0.05). The low-shrink posterior restorative showed similar surface roughness when compared to dimethacrylate composite resins and suitable to posterior restorations. (AU).

O objetivo deste estudo foi avaliar a rugosidade superficial de resinas compostas à base silorano e metacrilato submetidas a diferentes técnicas de acabamento/polimento. Foram preparadas 12 amostras de disco de cada resina composta: P90®, Z350® e Carisma, divididas em 12 grupos de acordo com a técnica de acabamento / polimento: sem acabamento / polimento (controle); acabamento com ponta diamantada 1112 FF; acabamento com ponta diamantada 1112 FF associada a Enhance / Pogo; acabamento com ponta diamantada 1112 FF associada a Enhance / Pogo / Polishing / Pastas Poli I e II / Fotogloss. Após as leituras iniciais da rugosidade da superfície, os espécimes foram submetidos a ciclos mecânicos (1.200.000 ciclos) e submetidos imediatamente a leituras de rugosidade final. As medias de rugosidade superfícial foram analisadas estatisticamente por ANOVA e teste de Tukey-Kramer (α = 0,05). As imagens de MEV foram realizadas após o acabamento / polimento e após a ciclagem mecânica. O compósito P90 mostrou valores de rugosidade superficial semelhantes a outros compósitos investigados. Tough, mostrou diferença significativa nas técnicas de acabamento / polimento. O grupo de pontas damantadas apresentou maior rugosidade superficial que diferiu das outras resinas compostas (α <0,05). Enance / Pogo mostrou os menores resultados, que não apresentaram diferença em relação ao grupo de pasta de polimento (α> 0,05). O material restaurador posterior de baixa contração apresentou rugosidade superficial semelhante quando comparado as resinas compostas de dimetacrilato e são restaurações adequadas para região posterior. (AU).

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.

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).

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.

Effect of organic acids in dental biofilm on microhardness of a silorane-based composite

OBJECTIVES: This study evaluated the effect of lactic acid and acetic acid on the microhardness of a silorane-based composite compared to two methacrylate-based composite resins. MATERIALS AND METHODS: Thirty disc-shaped specimens each were fabricated of Filtek P90, Filtek Z250 and Filtek Z350XT. After measuring of Vickers microhardness, they were randomly divided into 3 subgroups (n = 10) and immersed in lactic acid, acetic acid or distilled water. Microhardness was measured after 48 hr and 7 day of immersion. Data were analyzed using repeated measures ANOVA (p < 0.05). The surfaces of two additional specimens were evaluated using a scanning electron microscope (SEM) before and after immersion. RESULTS: All groups showed a reduction in microhardness after 7 day of immersion (p < 0.001). At baseline and 7 day, the microhardness of Z250 was the greatest, followed by Z350 and P90 (p < 0.001). At 48 hr, the microhardness values of Z250 and Z350 were greater than P90 (p < 0.001 for both), but those of Z250 and Z350 were not significantly different (p = 0.095). Also, the effect of storage media on microhardness was not significant at baseline, but significant at 48 hr and after 7 day (p = 0.001 and p < 0.001, respectively). Lactic acid had the greatest effect. CONCLUSIONS: The microhardness of composites decreased after 7 day of immersion. The microhardness of P90 was lower than that of other composites. Lactic acid caused a greater reduction in microhardness compared to other solutions.

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.

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. .

Repair on silorane-based composite

Introduction: Silorane-based composites have low polymerization shrinkage and good color stability. However, the effectiveness and the best surface treatment to carry out repairs to this type of restoration is unclear. Objective: To evaluate the effect of different types of repair made on a silorane-based composite. Material and methods: 80 disks of silorane-based composite were prepared (Filtek P90, 3M ESPE) and divided into eight groups (n = 10), according to the surface treatment being carried out before repairs of either the same silorane composite or a dimethacrylate material (Filtek Z350, 3M ESPE) were conducted. In two groups the immediate adhesion without repair (positive control) was evaluated. In other two groups repairs without any surface treatment (negative control) were evaluated. Surface treatments before the repair of the four remaining groups included the application of adhesive systems specific to silorane (Silorane System Adhesive, 3M ESPE) or to dimethacrylate (Adper Single Bond 2, 3M ESPE) and roughening followed by application of adhesive system. All groups were stored into distilled water at 37°C for 1 week prior to the microshear bond strength evaluation. Results: The group immediate adhesion silorane-dimethacrylate and group repair silorane-dimethacrylate without surface treatment showed lower microshear bond strength values and were statistically different from groups with surface treatment and immediate adhesion silorane-silorane (p < 0.05). Conclusion: Surface treatments with application of adhesive systems compatible with the repair material or roughening prior to the application of these adhesive systems are suitable for repairing silorane-based composites.

Effect of 38% carbamide peroxide on the microleakage of silorane-based versus methacrylate-based composite restorations

OBJECTIVES: This study aimed to assess the effect of 38% carbamide peroxide on the microleakage of class V cavities restored with either a silorane-based composite or two methacrylate-based composites. MATERIALS AND METHODS: A total of 96 class V cavities were prepared on the buccal surface of extracted human teeth with both enamel and dentin margins and were randomly assigned into three groups of Filtek P90 (3M-ESPE) + P90 system adhesive (3M-ESPE)(group A), Filtek Z250 (3M-ESPE) + Adper Prompt L-Pop (3M-ESPE)(group B) and Filtek Z350XT (3M-ESPE) + Adper Prompt L-Pop (group C). Half of the teeth were randomly underwent bleaching (38% carbamide peroxide, Day White, Discus Dental, applying for 15 min, twice a day for 14 day) while the remaining half (control) were not bleached. Dye penetration was measured following immersion in basic fuchsine. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests at a level of 0.05. RESULTS: No significant differences were found between composites in the control groups in enamel (p = 0.171) or dentin (p = 0.094) margins. After bleaching, microleakage of Z250 (in enamel [p = 0.867] or dentin [p = 0.590] margins) and Z350 (in enamel [p = 0.445] or dentin [p = 0.591] margins) did not change significantly, but the microleakage of P90 significantly increased in both enamel (p = 0.042) and dentin (p = 0.002) margins. CONCLUSIONS: No significant differences were noted between the bleached and control subgroups of two methacrylate-based composites in enamel or dentin margins. Microleakage of silorane-based composite significantly increased after bleaching.

The effect of resin thickness on polymerization characteristics of silorane-based composite resin

OBJECTIVES: This study examined the influence of the resin thickness on the polymerization of silorane- and methacrylate-based composites. MATERIALS AND METHODS: One silorane-based (Filtek P90, 3M ESPE) and two methacrylate-based (Filtek Z250 and Z350, 3M ESPE) composite resins were used. The number of photons were detected using a photodiode detector at the different thicknesses (thickness, 1, 2 and 3 mm) specimens. The microhardness of the top and bottom surfaces was measured (n = 15) using a Vickers hardness with 200 gf load and 15 sec dwell time conditions. The degree of conversion (DC) of the specimens was determined using Fourier transform infrared spectroscopy (FTIR). Scratched powder of each top and bottom surface of the specimen dissolved in ethanol for transmission FTIR spectroscopy. The refractive index was measured using a Abbe-type refractometer. To measure the polymerization shrinkage, a linometer was used. The results were analyzed using two-way ANOVA and Tukey's test at p < 0.05 level. RESULTS: The silorane-based resin composite showed the lowest filler content and light attenuation among the specimens. P90 showed the highest values in the DC and the lowest microhardness at all depth. In the polymerization shrinkage, P90 showed a significantly lower shrinkage than the rest two resin products (p < 0.05). P90 showed a significantly lower refractive index than the remaining two resin products (p < 0.05). CONCLUSIONS: DC, microhardness, polymerization rate and refractive index linearly decreased as specimen thickness linearly increased. P90 showed much less polymerization shrinkage compared to other specimens. P90, even though achieved the highest DC, showed the lowest microhardness and refractive index.

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.