Microhardness of dual-polymerizing resin cements and foundation composite resins for luting fiber-reinforced posts

Yoshida, Kazuhiko; Meng, Xiangjun

doi:10.1016/j.prosdent.2013.07.023

Cited by 10 publications

(8 citation statements)

References 28 publications

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“…However, the process of polymerization of resin cements was previously characterized using Knoop-hardness [30, 31]. Vickers [32, 33] and Knoop hardness [34] have been applied to test the degree of polymerization [32, 34] and polymerization shrinkage [33]. All 4 tested cements reached a constant level of hardness after 1 day of storage time, indicating that the polymerization was substantially finished.…”

Section: Discussionmentioning

confidence: 99%

Assessing degradation of composite resin cements during artificial aging by Martens hardness

2017

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BackgroundAim of the study was to verify the efficiency of Martens hardness measurements in detecting the degradation of composite resin cements during artificial aging.MethodsFour cements were used: Variolink II (VL2), RelyX Unicem 2 Automix (RUN), PermaFlo DC (PDC), and DuoCem (DCM). Specimens for Martens hardness measurements were light-cured and stored in water at 37 °C for 1 day to allow complete polymerization (baseline). Subsequently the specimens were artificially aged by water storage at 37 °C or thermal cycling (n = 6). Hardness was measured at baseline as well as after 1, 4, 9 and 16 days of aging. Specimens for indirect tensile strength measurements were produced in a similar manner. Indirect tensile strength was measured at baseline and after 16 days of aging (n = 10). The results were statistically analyzed using one-way ANOVA (α = 0.05).ResultsAfter water storage for 16 days hardness was significantly reduced for VL2, RUN and DCM while hardness of PDC as well as indirect tensile strength of all cements were not significantly affected. Thermal cycling significantly reduced both, hardness and indirect tensile strength for all cements. No general correlation was found between Martens hardness and indirect tensile strength. However, when each material was analyzed separately, relative change of hardness and of indirect tensile strength revealed a strong linear correlation.ConclusionsMartens hardness is a sensible test method to assess aging of resin composite cements during thermal cycling that is easy to perform.

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Section: Discussionmentioning

confidence: 99%

Assessing degradation of composite resin cements during artificial aging by Martens hardness

2017

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“…Additionally, the difficulty of curing lights to reach the most apical areas of roots canals (6,24) can impair the material polymerization, causing failure in the composite resin-dentin adhesive bond (25).…”

Section: Discussionmentioning

confidence: 99%

Effect of Light Sources on the Bond Strength of Resin Material to Thin-walled Roots

et al. 2014

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The aim of this study was to evaluate the bond strength to the dentin of an adhesive material used for root reinforcement light activated with different sources. Roots were divided into 4 groups (n=15) according to the light source used to activate the resin reinforcement: GI, non-weakened roots (control); GII, halogen light (H) 600 mW/cm 2 ; GIII, LED 800 mW/cm 2 and GIV, LED 1500 mW/cm 2 . The reinforcement was done with adhesive, composite resin and fiberglass posts. After 24 h, the specimens were sectioned and the first slice of each post region was used in the push out test in a universal testing machine with a crosshead speed of 0.5 mm/min. Failure modes of the debonded specimens were examined. Data (MPa) were analyzed by ANOVA and Holm-Sidak test (α=0.05). The second slice from each region was analyzed by scanning electron microscopy (SEM). LED-1500 (4.69 ± 1.74) provided bond strength similar to the control group (5.05 ± 2.63) and statistically different from H-600 (1.96 ± 0.94) and LED-800 (2.75 ± 1.90), which were similar to each other (p<0.05). Cervical (4.16 ± 2.32) and middle (4.43 ± 2.32) regions showed higher bond strength than the apical (2.25 ± 1.50) (p<0.05). There was a prevalence of adhesive failures in H-600 and LED-800 and cohesive failures in LED-1500. SEM showed the formation of long, numerous and fine tags. It was concluded that LED-1500 provided higher bond strength of resin reinforcement to the dentin.

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“…[1,14,18,[21][22][23] The autopolymerizing resin cement presented a totally opposite situation showing the highest hardness value in apical third, and the lowest value in cervical third, before and after thermocycling.…”

Section: Discussionmentioning

confidence: 99%

“…[10][11][12] These properties can be compromised if the cement does not reach its full polymerization, [13] accordingly, the root canal depth can hinder light irradiation, since it occurs from coronal to apical thirds, therefore, the cement can present different properties in the various depth levels into the cavity. [14,15] Microhardness testing has been described as a valid indirect method to determine the degree of cure because it presents a good correlation with the infrared spectroscopy approach. Since the degree of conversion achieved by a resin cement influence on its mechanical properties, biocompatibility and water and oral acids degradation, this work aims to analyze the microhardness and differences in cementation line at cervical, middle and apical cementing agents in cementation of fiberglass posts in bovine incisors submitted to thermocycling.…”

Section: Introductionmentioning

confidence: 99%

Microhardness of luting agents used for fiber post cementation submitted to thermo cycling

Zavanelli¹,

Mazaro²,

Kian³

et al. 2014

JCRI

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Aims and Objectives:The aim of this study was to analyze the microhardness of three resin cements used in cementing glass fiber posts in bovine incisor. The microhardness was analyzed in cervical, middle and apical thirds before and after thermocycling process. Materials and Methods: Bovine teeth were instrumented and divided into 3 groups composed of 10 teeth each. Then, the teeth were sectioned and obturated and had their canals prepared at a depth of 12mm. Once proceeded the desobturation, the roots and glass fiber posts were prepared for adhesive cementation. After cementation, the microhardness reading was carried out. After initial reading, the samples were placed in a thermocycler and subjected to 2,000 cycles and a new microhardness reading. The data collected were subjected to analysis of variance (ANOVA) and Turkey's test. Results: It was observed a statistical difference among the microhardness of resin cements. However, the statistical difference of microhardness before and after thermocycling appeared only in group U-200. Conclusion: Thermocycling reduced microhardness values in all cements evaluated in this study. The autopolymerizing cement Multilink presented the most stable microhardness mean values after thermocycling in the coronal, middle and apical thirds.

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Microhardness of dual-polymerizing resin cements and foundation composite resins for luting fiber-reinforced posts

Cited by 10 publications

References 28 publications

Assessing degradation of composite resin cements during artificial aging by Martens hardness

Assessing degradation of composite resin cements during artificial aging by Martens hardness

Effect of Light Sources on the Bond Strength of Resin Material to Thin-walled Roots

Microhardness of luting agents used for fiber post cementation submitted to thermo cycling

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