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Journal ArticleDOI

Polymerization kinetics of resin cements after light activation through fibre posts: an in vitro study.

01 Mar 2015-International Endodontic Journal (Newcastle University)-Vol. 48, Iss: 3, pp 261-267
TL;DR: The degree of conversion for VLV reduced after light activation through 9 mm Posts when compared to 3 mm and 6 mm posts, whilst the degree of Conversion for VLII decreased with every increase in post length.
Abstract: Aim To measure the polymerization of light-cured (Variolink Veneer, VLV) and dual-cured (Variolink II, VLII) resin luting cements after light activation through different lengths of fibre post ex vivo. Methodology Degree of conversion after prolonged direct light activation (PLA) [12 min after LED light activation for 3 min] was determined using ATR-FTIR. Models were then produced to allow samples of VLV and VLII (n = 5 each group) to be light-activated through 3, 6 and 9 mm lengths of fibre post (Fiber Lux). Degree of conversion was assessed by ATR-FTIR and expressed as a percentage of the degree of conversion achieved after PLA. Data were analysed using anova and Tukey's test (P < 0.05). Results Mean [SD] degree of conversion for VLV and VLII after PLA was 57.97% [1.51] and 54.71% [3.77], respectively. Light activation of VLV through a 3 mm post produced 81.62% of the PLA value, compared with 71.03% for the 6 mm and 46.04% for the 9 mm post. Conversion after activation through 9 mm posts was significantly less than through 3 mm and 6 mm posts (P < 0.05). For VLII, activation through a 3 mm post produced 66.51% of the PLA value, compared with 54.38% for the 6 mm and 41.56% for the 9 mm post. A significant decrease in degree of conversion was noted for VLII as post length increased (P < 0.05). Conclusions The degree of conversion for VLV reduced after light activation through 9 mm posts when compared to 3 mm and 6 mm posts, whilst the degree of conversion for VLII decreased with every increase in post length.

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Citations
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Journal ArticleDOI
TL;DR: The use of the Centrix syringe improved the homogeneity of the cement layer, reducing the defects in the layer and increasing adhesive strength values to dentin, even after mechanical cycling.
Abstract: Univ Estadual Paulista, UNESP, Inst Sci &Technol, BR-12245000 Sao Jose Dos Campos, SP, Brazil

20 citations

Journal ArticleDOI
TL;DR: The addition of 0.5 mol% DPIHFP improved the physical properties of dual‐polymerizing self‐adhesive resin cements and promoted less degradation after immersion in solvent.
Abstract: Statement of problem Dual-polymerizing self-adhesive resin cements present mechanical properties that may adversely affect the clinical performance of luted fiber-reinforced posts. Purpose The purpose of this in vitro study was to evaluate the properties of dual-polymerizing self-adhesive resin cements after the addition of an onium salt. Material and methods The experimental groups were set according to the molar concentration of diphenyliodonium hexafluorphosphate (DPIHFP) (0.5, 1, and 2 mol%). The resin cements were submitted to a push-out bond strength test and assessed for flexural strength (ISO 4049/2009), degree of conversion (Fourier-transformed infrared spectroscopy), depth of polymerization, swelling coefficient, and degradation in solvent. The data were statistically analyzed by ANOVA, Tukey test, Kruskal-Wallis test, Dunn multiple comparison, and paired Student t test (α=.05). Results All the RelyX U100 groups with onium salt showed the highest degree of conversion after 24 hours and 7 days ( P P =.054). The addition of 0.5 mol% DPIHFP increased the push-out bond strength and microhardness of RelyX U100 and promoted less degradation after immersion in solvent. The BisCem control group did not present a statistical difference from the experimental groups in terms of bond strength; the control group and the 0.5 mol% group showed no degradation in solvent. For swelling coefficient and flexural strength, no difference was found between the BisCem groups ( P =.067 and P =.173), and the RelyX U100 2 mol% group presented the lower value ( P P =.048). Depth of polymerization was not statistically different in the experimental groups for either resin cement ( P =.999). Conclusions The addition of 0.5 mol% DPIHFP improved the physical properties of dual-polymerizing self-adhesive resin cements.

9 citations


Cites background from "Polymerization kinetics of resin ce..."

  • ...For intracanal post cementation, light penetration is insufficient for polymerizing the material along the root canal.(5,6) Therefore, the use of dual-polymerizing resin cements is necessary to achieve increased strength in the middle and apical thirds of the canal....

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Journal ArticleDOI
TL;DR: Surface treatment of fiber post with TiF4 (4 wt/v%-4 min) solution exhibited higher bond strength to resin cement compared with other surface treatments, and flexural properties and microtensile bond strength were determined.
Abstract: This study evaluated the effect of titanium tetrafluoride (TiF4) solution on the bond strength of glass fiber post to resin cement. The specimens were divided into eight groups according to the method of surface treatment performed. Flexural properties and microtensile bond strength (µTBS) were determined. Data were analyzed using two-way ANOVA and Tukey's post hoc tests. The highest µTBS achieved with the TiF4 (4 wt/v%-4 min) group compared with the other groups (p 0.05). Surface treatment of fiber post with TiF4 (4 wt/v%-4 min) solution exhibited higher bond strength to resin cement compared with other surface treatments.

6 citations

Journal ArticleDOI
TL;DR: A quantitative investigation of the radial transmission of light through different fiber posts and its influence on the Knoop hardness number (KHN) and bond strength (BS) of a dual-cure self-adhesive resin cement at 3 different depths found LT depended on the type of post and on depth.
Abstract: Context: Light transmission (LT) into deeper areas of the dentin root is limited. Aim: The aim of this study is to perform a quantitative investigation of the radial transmission of light (LT) through different fiber posts and its influence on the Knoop hardness number (KHN) and bond strength (BS) of a dual-cure self-adhesive resin cement at 3 different depths. Materials and Methods: Four types of fiber posts (2 translucent and 2 conventional) were used. LT and KHN analyses were performed in a specially designed matrix, which allowed measurements at 3 different depths. LT was measured using a volt-ampere meter while KHN tests were performed in a microhardness tester. For BS analysis, endodontically treated bovine roots were divided into 4 groups, each group receiving one type of post. After cementation, cross sections of the root were tested for resistance to displacement using a universal testing machine. Statistical Analysis Used: Statistical analysis was performed by using this ANOVA and Tukey's test. Results: For LT, translucent posts showed significantly higher values at all depths compared to the conventional ones. For all posts, LT decreased at the deeper depths. The KHN results showed no statistical differences among the different posts, regardless of depth. For BS, a translucent post showed the highest values, and comparative analyses between the different depths of posts also showed statistically significant differences while comparisons among the different depths of the same post showed no differences. Conclusions: LT depended on the type of post and on depth. The type of post did not significantly influence the cement KHN. A translucent post showed higher BS in pooled data.

3 citations


Cites background from "Polymerization kinetics of resin ce..."

  • ...Although studies have revealed unfavorable results concerning the amount of luminous energy transmitted through translucent posts,[10,15,17,23,29,30] some of the manufacturers promise a sufficient transmission of light...

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Journal ArticleDOI
TL;DR: In this paper, the degree of conversion (DoC) of self-adhesive resin luting cements when irradiated through different fiber post lengths was evaluated with a total reflectance Fourier transform infrared spectroscopy reading.
Abstract: Purpose To evaluate the degree of conversion (DoC) of self-adhesive resin luting cements when irradiated through different fiber post lengths. Methods A total of 60 teeth were sectioned to achieve lengths of 4 mm, 7 mm, and 10 mm, while 60 fiber posts were trimmed to give 3 mm, 6 mm, and 9 mm lengths. Post space was created to accommodate the fiber post and 1 mm of luting cement apically. Two self-adhesive resin luting cements (Multilink Speed and RelyX U200) were used. A total of four cycles of 20 s irradiation was done with an attenuated total reflectance Fourier transform infrared spectroscopy reading between each cycle. Results The mean ± standard deviation DoC achieved with a light-emitting diode and quartz tungsten halogen for Multilink Speed was 67.4 ± 2.7% and 72.4 ± 4.0%, respectively, while for RelyX U200, the corresponding values were 56.5 ± 2.7% and 62.0 ± 3.8%, respectively. For Multilink Speed, there was no significant difference between the control and the 3 mm group, while for RelyX U200, no significant difference was found between the 6 mm and 9 mm groups. All the other groups showed significant differences. Conclusion The DoC reduced as the post length increased.

2 citations

References
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Journal ArticleDOI
TL;DR: The curing efficiency of 4 high-intensity light-emitting diode (LED) devices was evaluated by assessing percentage of residual C=C, surface microhardness (SM), depth of cure (DC), percentage of linear shrinkage-strain (LS), and percentage of wall-to-wall contraction (WWC).
Abstract: We evaluated the curing efficiency of 4 high-intensity light-emitting diode (LED) devices by assessing percentage of residual C=C (%RDB), surface microhardness (SM), depth of cure (DC), percentage of linear shrinkage-strain (%LS), and percentage of wall-to-wall contraction (%WWC). The light-curing units tested were a QTH light, the Elipar TriLight (3M/ESPE), and 4 LED devices - the Allegro (Denmat), the Bluephase (Ivoclar/Vivadent), the FreeLight2 (3M/ESPE), and The Cure TC-01 (Spring Health Products). The %RDB was measured by microFTIR spectroscopy. Microhardness measurements (Vickers) were performed at the surface (H0) and at depths of 3 mm (H3) and 5 mm (H5) of cylindrical specimens. Depth of cure was expressed as the ratio of microhardness at each depth, relative to the corresponding surface value (H3/H0 and H5/H0). The bonded disc method was used to evaluate %LS. For the %WWC evaluation, cylindrical resin restorations were imaged by high resolution micro-CT and the %WWC was calculated at depths of 0 mm and 2 mm. There were no statistical differences among the LEDs in %RDB or %LS. The Bluephase and Allegro had the highest SM values. As compared with the other LEDs, the Bluephase and The Cure TC-01 had lower values for depth of cure at depths of 3 mm and 5 mm. There were no significant differences in %WWC among the LEDs at either depth, and the QTH had the lowest %WWC at both depths. (J Oral Sci 52, 187-195, 2010)

36 citations

Journal ArticleDOI
TL;DR: For the two bonding systems tested, it appears that light curing of the adhesive is important in order to reach a high DC in the first moments after the bonding procedure.

31 citations


"Polymerization kinetics of resin ce..." refers background in this paper

  • ...Previ- ous studies have used the aromatic C=C peak at around 1610 cm 1 (Spencer et al. 2000, Faria-e-Silva et al. 2008, Kim et al. 2009), but this peak was absent for VLV, which is likely to be due to the absence of Bis-GMA, therefore ruling out the use of this peak for investigation....

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  • ...Published by John Wiley & Sons Ltd 261 expected to allow deeper penetration of light and improved conversion (Shadman et al. 2012), but inadequate conversion rates have been reported in middle and apical root thirds (Faria-e-Silva et al. 2008, Kim et al. 2009)....

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Journal ArticleDOI
TL;DR: The study indicates that polymerization of resin cements with different light-curing units may result in various polymer structures, and consequently different mechanical and physical properties.
Abstract: OBJECTIVE: The aim of this study was to compare the polimerization ability of three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) and their exposure modes (high-intensity and soft-start) by determination of microhardness, water sorption and solubility, and diametral tensile strength of 5 dual-curing resin cements. Material and methods: A total of 720 disc-shaped samples (1 mm height and 5 mm diameter) were prepared from different dual-curing resin cements (Duolink, Nexus, Bifix-QM, Panavia F and RelyX Unicem). Photoactivation was performed by using quartz tungsten halogen (high-power and soft-up modes), light-emitting diode (standard and exponential modes) and plasma arc (normal and ramp-curing modes) curing units through ceramic discs. Then the samples (n=8/per group) were stored dry in the dark at 37°C for 24 h. The Vickers hardness test was performed on the resin cement layer with a microhardness tester (Shimadzu HMV). For sorption and solubility tests; the samples were stored in a desiccator at 37°C and weighed to a constant mass. The samples were weighed both before and after being immersed in deionized water for different periods of time (24 h and 7 days) and being desiccated. The diametral tensile strength of the samples was tested in a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by nonparametric Kruskal Wallis and Mann-Whitney U tests at 5% significance level. RESULTS: Resin cement and light-curing unit had significant effects (p 0.05) were obtained with different modes of LCUs. Conclusion: The study indicates that polymerization of resin cements with different light-curing units may result in various polymer structures, and consequently different mechanical and physical properties.

28 citations


"Polymerization kinetics of resin ce..." refers background in this paper

  • ...The detailed dynamics of adhesive behaviour within post channels is, however, under-researched, and concerns have been expressed about the quality of curing as a function of compromised light penetration (Cekic-Nagas & Ergun 2011)....

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Journal ArticleDOI
TL;DR: The effective radiance along the post was diminished exponentially, which features the insufficient polymerization of a dual-cured resin cement surrounding the posts at apical region and might therefore influence the microleakage of post-restored teeth.

26 citations


"Polymerization kinetics of resin ce..." refers methods in this paper

  • ...The Fiber Lux post used in this study is glass fibre, and light transmission through this post is significantly greater than through an opaque glass fibre post from the same manufacturer, but light transmission drops by approximately 95% between 1 mm and 9 mm length (Ho et al. 2011)....

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Journal ArticleDOI
TL;DR: Using real-time Fourier transform infrared (FTIR)-attenuated total reflection (ATR) spectroscopy, photopolymerization and photobleaching of n-butyl acrylate/fumed silica composites were characterized in this article.

23 citations