Effect of different composite core materials on fracture resistance of endodontically treated teeth restored with FRC posts

Abstract Objective This study evaluated the fracture resistance of endodontically treated teeth restored with fiber reinforced composite posts, using three resin composite core build-up materials, (Clearfil Photo Core (CPC), MultiCore Flow (MCF), and LuxaCore Z-Dual (LCZ)), and a nanohybrid composite, (Tetric N-Ceram (TNC)). Material and Methods Forty endodontically treated lower first premolars were restored with quartz fiber posts (D.T. Light-Post) cemented with resin cement (Panavia F2.0). Samples were randomly divided into four groups (n=10). Each group was built-up with one of the four core materials following its manufacturers’ instructions. The teeth were embedded in acrylic resin blocks. Nickel-Chromium crowns were fixed on the specimens with resin cement. The fracture resistance was determined using a universal testing machine with a crosshead speed of 1 mm/min at 1350 to the tooth axis until failure occurred. All core materials used in the study were subjected to test for the flexural modulus according to ISO 4049:2009. Results One-way ANOVA and Bonferroni multiple comparisons test indicated that the fracture resistance was higher in the groups with CPC and MCF, which presented no statistically significant difference (p>0.05), but was significantly higher than in those with LCZ and TNC (p<0.05). In terms of the flexural modulus, the ranking from the highest values of the materials was aligned with the same tendency of fracture loads. Conclusion Among the cores used in this study, the composite core with high filler content tended to enhance fracture thresholds of teeth restored with fiber posts more than others.

The effects of shade and light irradiation on the polymerization of composite resin core materials / 实用口腔医学杂志

Objective:To evaluate the effects of shade and light irradiation condition on the polymerization of composite resin core material.Methods:The light-proof silicon rubber cuboid mold with one end open were stringed and filled by dual-cured flowable composite resin core material with the shade of dentine and white(Paracore) respectively,then the open end of mold was irradiated directly by a light unit at 1 000 mW/cm2 ×20 s and 3 200 mW/cm2 ×6 s respectively.And all specimens of 4 groups(n =5) were stored in the light-proof box.1 h and 24 h after irradiation,Knoop microhardness was measured along the vertical surfaces of the specimens at the depth of 1,2 and 3 mm respectively.Data were analyzed by One-way ANOVA.Results:At all light irradiation conditions,the hardness of all specimens decreased with the increase of measurement depth.24 h after irradiation,the hardness of dentine shade specimens at each measurement depth showed no difference between 1 000 mW/cm2 × 20 s and 3 200 mW/cm2 × 6 s irradiation,while the white shade specimens irradiated by 1 000 mW/cm2 × 20 s showed higher hardness than those by 3 200 mW/cm2 × 6 s.Conclusion:To obtain sufficient polymerization of composite core material with different shade optimal light irradiation condition should be selected.

Research on bond durability among different core materials and zirconia ceramic cemented by self-adhesive resin cements / 华西口腔医学杂志

<p><b>OBJECTIVE</b>This research estimated shear bond durability of zirconia and different substrates cemented by two self-adhesive resin cements (Clearfil SA Luting and RelyX U100) before and after aging conditioning.</p><p><b>METHODS</b>Machined zirconia ceramic discs were cemented with four kinds of core material (cobalt-chromium alloy, flowable composite resin core material, packable composite resin, and dentin) with two self-adhesive resin cements (Clearfil SA Luting and RelyX U100). All specimens were divided into eight test groups, and each test group was divided into two subgroups. Each subgroup was subjected to shear test before and after 10 000 thermal cycles.</p><p><b>RESULTS</b>All factors (core materials, cements, and thermal cycle) significantly influenced bond durability of zirconia ceramic (P<0.00 1). After 10 000 thermal cycles, significant decrease was not observed in shear bond strength of cobalt-chromium alloy luted with Clearfil SA Luting (P>0.05); observed shear bond strength was significantly higher than those of other substrates (P<0.05). Significantly higher shear bond strength was noted in Clearfil SA Luting luted with cobalt-chromium alloy, flowable composite resin core material, and packable composite resin than that of RelyX U100 (P<0.05). However, significant difference was not observed in shear bond strength of dentin luted with Clearfil SA Luting and RelyX U100 (P>0.05).</p><p><b>CONCLUSIONS</b>Different core materials and self-adhesive resin cements can significantly affect bond durability of zirconia ceramic. 
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Effects of Different Materials Post-core Restoration on Fracture Resistance of Weakened Roots / 中国医科大学学报

Objective To investigate the influence of different kinds of post?core materials on fracture resistant ability of different walls during weakened root restoration. Methods Forty?eight human single root mandibular first premolars were randomly assigned to two groups(groupⅠwas repaired with quartz?fiber post?core and mental crown ,and groupⅡwas repaired with Co?Cr cast metal post?core and mental crown). Each main group was then divided into four subgroups of 6 specimens. All samples were tested on the universal test machine. We observed the fracture load and the fracture mode of the specimens. Results Cr?Co ally post?core group exhibited significantly higher resistance to fracture than quartz fiber post?core in the same number weakened root walls(P<0.05). With the increase in the quantity of weakened root walls ,the fracture resistance was significant decreased in the same post?core material(P<0.05). The possibility of repairable fractures in groupⅠwas significantly higher than that in groupⅡ(P<0.05). Conclusion Cr?Co alloy post?core can bear a higher bite ,but quartz fiber post?core has the most favorable fracture modes.

Influência de diferentes métodos de condicionamento superficial em pinos pré-fabricados resinosos fibro-reforçados em vidro e quartzo na resistência adesiva a compósito de polimerização dual: teste de push-out / Influence of different pretreatments in glass and quartz fiber posts on the bond strength of a dual-cure resin core material: push-out test

O objetivo deste estudo foi realizar uma avaliação tridimensional da rugosidade superficial em 3 tipos de pinos de fibra - DT LightPost®, FRC Postec Plus® e Transluma Post™ - submetidos a diferentes tratamentos de superfície e avaliar os efeitos dos pré-tratamentos na resistência adesiva a um compósito de presa dual Biscore™. Os tratamentos de superfície foram: imersão em ácido hidrofluorídrico, jateamento com óxido de alumínio a 50µm, imersão em peróxido de hidrogênio, jateamento com óxido de alumínio a 50µm seguido de imersão em ácido hidrofluorídrico e jateamento com óxido de alumínio a 50µm seguido de imersão em peróxido de hidrogênio. No experimento 1, 75 pinos foram divididos em 3 grupos (n = 25), de acordo com seu fabricante e subdivididos em cinco subgrupos. A rugosidade superficial foi medida usando um rugosímetro tridimensional e analisada com o software de análise 3D. Os valores de rugosidade foram obtidos antes e após diferentes tratamentos de superfície na área dos mesmos corpos-de-prova. Para o experimento 2, foram utilizados os mesmos corpos-de-prova, os mesmos grupos e subgrupos do experimento 1, tendo sido adicionado o subgrupo de controle (n=90) e a resistência adesiva a um compósito presa dual Biscore™ foi mensurada através de um teste push-out. A resistência adesiva foi medida em uma máquina universal de ensaios, com uma célula de carga tipo SLBL-5kN em uma velocidade de 0,5 mm / min. Os resultados do experimento 1 foram analisados através de um teste estatístico t-Student. Jateamento e jateamento seguido de imersão em ácido hidrofluorídrico produziram um aumento estatisticamente significante na rugosidade, contudo somente o tratamento por jateamento proporcionou um aumento significativo nos valores de rugosidade. Os resultados do experimento 2 foram obtidos através de um um teste t-unilateral de hipótese com variância desconhecida. Concluiu-se que o jateamento com óxido de alumínio a 50μm em uma distância de 30 mm a 2,5 bar ...

The aim of this study was to perform a tridimensional surface roughness test evaluation of different surface treatments to 3 types of fiber posts - DT LightPost®, FRC Postec Plus® e Transluma Post™ - and evaluate the effects of the different pretreatments on the bond strength of a dual-cure resin core material Biscore™. The different surface treatments were: immersion in hydrofluoric acid, sandblasting abrasion with 50 µ alumina particles, immersion in hydrogen peroxide, sandblasting abrasion with 50 µ alumina particles followed by immersion in hydrofluoric acid and sandblasting abrasion with 50 µ alumina particles followed by immersion in hydrogen peroxide. In the first experiment seventy five fiber posts were divided into 3 groups (n = 25), according to their manufacturer and subdivided into 5 subgroups. Surface roughness was measured using a tridimensional surface roughness test and analyzed with 3D analysis software. Surface roughness was obtained before and after the different surface treatments at the same post area. In the second experiment the same samples divided in groups and subgroups were used, but a control group (no treatment) was added (n = 90) and the bond strength to a composite resin core material Biscore™ was measured using a push-out design. The interfacial push-out bond strength was measured in a universal testing machine, with a load cell type SLBL-5kN at a crosshead speed of 0.5 mm/min. Results in experiment 1 were statistically analyzed using Student´s t-Test. Sandblasting and sandblasting followed by immersion in hydrofluoric acid produced a significant increase in roughness, but the sandblasting treatment was able to provide a significant roughness increase. Results in experiment 2 were statistically analysed using one-sided t-Test of Hypothesis with unknown variance. It was concluded that sandblasting airborne-particle abrasion with alumina 50µ at a distance of 30 mm at 2.5 bars pressure for 5 seconds was ...

Influência de diferentes métodos de condicionamento superficial em pinos pré-fabricados resinosos fibro-reforçados em vidro e quartzo na resistência adesiva a compósito de polimerização dual: teste de push-out / Influence of different pretreatments in glass and quartz fiber posts on the bond strength of a dual-cure resin core material: push-out test

O objetivo deste estudo foi realizar uma avaliação tridimensional da rugosidade superficial em 3 tipos de pinos de fibra - DT LightPost®, FRC Postec Plus® e Transluma Post™ - submetidos a diferentes tratamentos de superfície e avaliar os efeitos dos pré-tratamentos na resistência adesiva a um compósito de presa dual Biscore™. Os tratamentos de superfície foram: imersão em ácido hidrofluorídrico, jateamento com óxido de alumínio a 50µm, imersão em peróxido de hidrogênio, jateamento com óxido de alumínio a 50µm seguido de imersão em ácido hidrofluorídrico e jateamento com óxido de alumínio a 50µm seguido de imersão em peróxido de hidrogênio. No experimento 1, 75 pinos foram divididos em 3 grupos (n = 25), de acordo com seu fabricante e subdivididos em cinco subgrupos. A rugosidade superficial foi medida usando um rugosímetro tridimensional e analisada com o software de análise 3D. Os valores de rugosidade foram obtidos antes e após diferentes tratamentos de superfície na área dos mesmos corpos-de-prova. Para o experimento 2, foram utilizados os mesmos corpos-de-prova, os mesmos grupos e subgrupos do experimento 1, tendo sido adicionado o subgrupo de controle (n=90) e a resistência adesiva a um compósito presa dual Biscore™ foi mensurada através de um teste push-out. A resistência adesiva foi medida em uma máquina universal de ensaios, com uma célula de carga tipo SLBL-5kN em uma velocidade de 0,5 mm / min. Os resultados do experimento 1 foram analisados através de um teste estatístico t-Student. Jateamento e jateamento seguido de imersão em ácido hidrofluorídrico produziram um aumento estatisticamente significante na rugosidade, contudo somente o tratamento por jateamento proporcionou um aumento significativo nos valores de rugosidade. Os resultados do experimento 2 foram obtidos através de um um teste t-unilateral de hipótese com variância desconhecida. Concluiu-se que o jateamento com óxido de alumínio a 50μm em uma distância de 30 mm a 2,5 bar ...

The aim of this study was to perform a tridimensional surface roughness test evaluation of different surface treatments to 3 types of fiber posts - DT LightPost®, FRC Postec Plus® e Transluma Post™ - and evaluate the effects of the different pretreatments on the bond strength of a dual-cure resin core material Biscore™. The different surface treatments were: immersion in hydrofluoric acid, sandblasting abrasion with 50 µ alumina particles, immersion in hydrogen peroxide, sandblasting abrasion with 50 µ alumina particles followed by immersion in hydrofluoric acid and sandblasting abrasion with 50 µ alumina particles followed by immersion in hydrogen peroxide. In the first experiment seventy five fiber posts were divided into 3 groups (n = 25), according to their manufacturer and subdivided into 5 subgroups. Surface roughness was measured using a tridimensional surface roughness test and analyzed with 3D analysis software. Surface roughness was obtained before and after the different surface treatments at the same post area. In the second experiment the same samples divided in groups and subgroups were used, but a control group (no treatment) was added (n = 90) and the bond strength to a composite resin core material Biscore™ was measured using a push-out design. The interfacial push-out bond strength was measured in a universal testing machine, with a load cell type SLBL-5kN at a crosshead speed of 0.5 mm/min. Results in experiment 1 were statistically analyzed using Student´s t-Test. Sandblasting and sandblasting followed by immersion in hydrofluoric acid produced a significant increase in roughness, but the sandblasting treatment was able to provide a significant roughness increase. Results in experiment 2 were statistically analysed using one-sided t-Test of Hypothesis with unknown variance. It was concluded that sandblasting airborne-particle abrasion with alumina 50µ at a distance of 30 mm at 2.5 bars pressure for 5 seconds was ...

Comparison of mechanical properties of various post and core materials / 대한치과보철학회지

STATEMENT OF PROBLEM: Many kinds of post and core systems are in the market, but there are no clear selection criteria for them. PURPOSE: The purpose of this study was to compare the flexural strength and modulus of elasticity of core materials, and measure the bending strength of post systems made of a variety of materials. MATERIAL AND METHODS: The flexural strength and elastic modulus of thirteen kinds core buildup materials were measured on beams of specimens of 2.0 x 2.0 x 24 +/- 0.1mm. Ten specimens per group were fabricated and loaded on an Instron testing machine at a crosshead speed of 0.25mm/min. A test span of 20 mm was used. The failure loads were recorded and flexural strength calculated with the measured dimensions. The elastic modulus was calculated from the slopes of the linear portions of the stress-strain graphs. Also nine kinds commercially available prefabricated posts made of various materials with similar nominal diameters, approximately 1.25mm, were loaded in a three-point bend test until plastic deformation or failure occurred. Ten posts per group were tested and the obtained data were anaylzed with analysis of variance and compared with the Tukey multiple comparison tests. RESULTS: Clearfil Photo Core and Luxacore had flexural strengths approaching amalgam, but its modulus of elasticity was only about 15% of that of amalgam. The strengths of the glass ionomer and resin modified glass ionomer were very low. The heat pressed glass ceramic core had a high elastic modulus but a relatively low flexural strength approximating that of the lower strength composite resin core materials. The stainless steel, zirconia and carbon fiber post exhibited high bending strengths. The glass fiber posts displayed strengths that were approximately half of the higher strength posts. CONCLUSION: When moderate amounts of coronal tooth structure are to be replaced by a post and core on an anterior tooth, a prefabricated post and high strength, high elastic modulus core may be suitable.

THE PHYSCIAL PORPERTIES OFY Y2O3-CONTAINING GLASS INFILTRATED ALUMINA CORE MADE BY PRESSURELESS POWDER PACKING METHOD / 대한치과보철학회지

The objective of this study was to characterize the mechanical properties of Y2O3-containing glass infiltrated ceramic core material, which was made by pressureless powder packing method. A pure alumina powder with a grain size of about 4micrometer was packed without pressure is silicon mold to form a bar shaped sample, and applied PVA solution as a binder. Samples were sinterd at 1350degrees C for 1 hour. After cooling, Y2O3-containing glass (SiO2, Y2O3, B2O3, Al2O3, ect) was infiltrated to the sinterd samples at 1300degrees C for 2 hours and cooled. Six different proportions Y2O3 of were used to know the effect of the mismatch of the thermal expansion coefficient between alumina powder and glass. The samples were ground to 3x3x30 mm size and polished with 1microneter diamond paste. Flexural strength, fracture toughness, hardness and other physical properties were obtained, and the fractured surface was examined with SEM and EPMA. Ten samples of each group were tested and compared with In-Ceram(TM) core materials of same size made in dental laboratory. The results were as follows : 1. The flexural strengths of group 1 and 3 were significantly not different with that of In-Ceram, but other experimental groups were lower than In-Ceram. 2. The shrinkage rate of samples was 0.42% after first firing, and 0.45% after glass infiltration. Total shrinkage rate was 0.87%. 3. After first firing, porosity rate of experimental groups was 50%, compared with 22.25% of In-Ceram. After glass infiltration, porosity rate of experimental groups was 2%, and 1% in In-Ceram. 4. There was no statistical difference in hardness between two materials tested, but in fracture toughness, group 2 and 3 were higher than In-Ceram. 5. The thermal expansion coefficients of experimental groups were varied to 4.51~5.35x10-6/degrees C according to glass composition, also the flexural strengths of samples were varied. 6. In a view of SEM, many microparticles about 0.5microneter diameter and 4microneter diameter were observed in In-Ceram. But in experimental group, the size of most particles was about 4microneter, and a little microparticles was observed. The results obtained in this study showed that the mismatch of the thermal expansion coefficients between alumina powder and infiltrated glass affect the flexural strength of alumin/glass composite. The Y2O3-containing glass infiltrated ceramic core made by powder packing method will takes less time and cost with sufficient flexural strength similar to all ceramic crown made with slip casting technique.