Evaluation of the surface hardness of composite resins before and after polishing at different times

Chinelatti, Michelle Alexandra; Chimello, Daniela Thomazatti; Ramos, Renata Pereira; Palma-Dibb, Regina Guenka

doi:10.1590/s1678-77572006000300008

Cited by 36 publications

(37 citation statements)

References 19 publications

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“…Studies have demonstrated that water absorption by the matrix and oral temperature conditions may cause failures in these materials, altering the cohesion between the matrix and inorganic particles, consequently reducing their mechanical properties 22,[7][8][9][10][11] . The results of our study confirm this assertion since the resins with an organic matrix similarity showed similar mechanical behavior with regards to hardness.…”

Section: Discussionmentioning

confidence: 99%

“…Hardness determines the degree of deformation of a material and is generally accepted as an important property and a valuable parameter for comparison with the tooth structure 8 . To assess hardness, tests based on the materials' capacity to resist the penetration of a tip are performed, and the Knoop hardness test is the most commonly indicated method for resin composites 6 .…”

Section: Introductionmentioning

confidence: 99%

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Analysis of surface hardness of artificially aged resin composites

Tornavoi

Satoa²,

Silva

et al. 2012

Mat. Res.

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This study evaluated the effect of artificially accelerated aging (AAA) on the surface hardness of eight composite resins: Filtek Z250, Filtek Supreme, 4 Seasons, Herculite, P60, Tetric Ceram, Charisma, and Filtek Z100. Sixteen specimens were made from the test piece of each material, using an 8.0 × 2.0 mm teflon matrix. After 24 hours, eight specimens from each material were submitted to three surface hardness readings using a Shimadzu Microhardness Tester for 5 seconds at a load of 50 gf. The other eight specimens remained in the artificially accelerated aging machine for 382 hours and were submitted to the same surface hardness analysis. The means of each test specimen were submitted to the Kolmogorov-Smirnov test (p > 0.05), ANOVA and Tukey test (p < 0.05). With regard to hardness (F = 86.74, p < 0.0001) the analysis showed significant differences among the resin composite brands. But aging did not influence the hardness of any of the resin composites (F = 0.39, p = 0.53). In this study, there was interaction between the resin composite brand and the aging factors (F = 4.51, p < 0.0002). It was concluded that notwithstanding the type of resin, AAA did not influence surface hardness. However, with regard to hardness there was a significant difference among the resin brands.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of surface hardness of artificially aged resin composites

Tornavoi

Satoa²,

Silva

et al. 2012

Mat. Res.

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“…Therefore polishing was not carried out. Polishing also may result in heat generation that may affect polymerization [31]. Also, the use of Mylar strips in this study resulted in smooth and clear surfaces for the ease of VH indentation, which eliminated the need for surface polishing.…”

Section: Sample Thicknessmentioning

confidence: 91%

“…The latter has been shown to affect the reading of FTIR and micro-Raman when measuring the DC. As to the effect of polishing on VH measurements, it was reported that polishing sample surface will result in a higher VH value [31]. Conversely, Chung and Yap [32] concluded that surface hardness was independent of the surface finish provided because the indenter penetration was sufficiently deep.…”

Section: Sample Thicknessmentioning

confidence: 99%

“…Conversely, Chung and Yap [32] concluded that surface hardness was independent of the surface finish provided because the indenter penetration was sufficiently deep. In addition, in this study, the bottom to top surface VH ratio (%) was recorded and not each surface value in isolation, thus this should not affect the ratio as neither surface was polished [31]. Polishing of the composite surfaces is not clinically relevant and does not simulate the clinical situation especially when polishing the bottom surface.…”

Section: Sample Thicknessmentioning

confidence: 99%

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Bulk Fill Resin Composite Materials Cured with Single-Peak versus Dual-Peak LED LCUs

Aldossary

Roebuck

Santini

2016

Acta Medica Marisiensis

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Introduction: Manufactures claim that recently introduced bulk fill materials (BFM) can be cured adequately in 4 mm increments. This requires adequate light energy to be transmitted through the material to ensure adequate polymerization at the bottom of the increment. Aim: To compare the total light energy transmission through three BFMs and bottom/top (B/T) surface Vickers hardness (VH) when cured with single-peak versus dual-peak LED LCUs. Methods and Materials: Samples (n=5) of two viscous BFMs, Tetric EvoCeram ® Bulk Fill X-tra fil ® [XF] flowable SureFil, were prepared. A conventional RBC, Tetric EvoCeram ® was used as a control. Using MARC ® RC, the irradiance delivered to top surface of samples was adjusted to 1200 mW/cm 2 . Samples were cured with singlepeak EliparTM S10 or dual-peakBluephase ® G2 for 10 seconds and irradiance transmitted to the bottom surface measured. Samples were stored for 24 hours, prior to VH measurements B/T VH ratios were calculated. Statistically analysed used oneway ANOVA (α=0.05).Results: There was no statistically significant difference for B/T total energy transmission between materials except XF with EliparTM S10 (P<0.001). Total energy transmission ranged from 0.7 J/cm2 to 1.5 J/cm2. There was no statistically significant difference for B/T VH ratios between materials (P>0.05) when materials were cured with single-peak versus dual-peak LCU's, XF>SDR>TEC>TBF. TBF alone, did not reach the generally accepted B/T VH of 80%. Conclusions: Both single-peak and dual-peak LCU's were equally effective for curing the studied bulk fill materials. Manufacture's recommended total energy delivered to the top surface may not always be sufficient for effective curing.

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Wear of nanofilled dental composites at varying filler concentrations

Lawson

Burgess

2014

J Biomed Mater Res

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The aim of this study is to examine the effects of nanofiller concentration on the mechanisms of wear of a dental composite. Nanofilled composites were fabricated with a bisphenol A glycidyl methacrylate polymer and 40 nm SiO2 filler particles at three filler loads (25, 50, and 65 wt %). The elastic modulus, flexural strength, and hardness of the composites and the unfilled resin were measured. The materials (n = 8) were tested in the modified wear testing device at 50,000, 100,000, and 200,000 cycles with 20N force at 1 Hz. A 33% glycerine lubricant and stainless steel antagonist were used. The worn composite and antagonist surfaces were analyzed with noncontact profilometry and SEM. The volumetric wear data indicated that there are significant differences between filler concentrations and cycles (p < 0.05). A trend was noted that increasing filler content beyond 25% decreased the wear resistance of the composites. Increasing filler content increased hardness and modulus and increased flexural strength up to 50% fill. SEM evaluation of the worn specimens indicated that the resin and 25% filled materials exhibited cracking and failed by fatigue and the 50 and 65% filled materials exhibited microcutting and failed by abrasive wear. Based on the results of this study, composite manufacturers are recommended to use a filler concentration between 25 and 50% when using nanosized filler particles.

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Evaluation of the surface hardness of composite resins before and after polishing at different times

Cited by 36 publications

References 19 publications

Analysis of surface hardness of artificially aged resin composites

Analysis of surface hardness of artificially aged resin composites

Bulk Fill Resin Composite Materials Cured with Single-Peak versus Dual-Peak LED LCUs

Wear of nanofilled dental composites at varying filler concentrations

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