Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement

Paula, Andréia Bolzan de; Tango, Rubens Nisie; Sinhoreti, Mário Alexandre Coelho; Alves, Marcelo Corrêa; Puppin-Rontani, Regina Maria

doi:10.1590/s0103-64402010000200005

Cited by 16 publications

(13 citation statements)

References 15 publications

(14 reference statements)

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“…Some clinical scenarios do not allow adequate polymerization of resin-based materials due to strong light attenuation caused by the distance from the light source and absorbing characteristics of restorative materials (1)(2)(3)(4). Curing light attenuation compromises the mechanical and adhesive properties of the resin cement because the low light intensity that reaches the resin cement is not sufficient to produce a high degree of conversion (DC) (5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

Indirect Restoration Thickness and Time after Light-Activation Effects on Degree of Conversion of Resin Cement

et al. 2015

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This study evaluated the effects of indirect restorative materials, curing conditions and time on the degree of conversion (DC) of a dual-cured resin cement using infrared spectroscopy. The resin cement (RelyX Unicem 2, 3M ESPE) was applied to the diamond surface of a horizontal attenuated-total-reflectance unit and activated using one of following conditions: self-cure, direct light exposure, light exposure through indirect restorative materials (resin nano-ceramic: Lava Ultimate, 3M ESPE or feldspathic ceramic: Vita Blocks Mark II, Vita Zahnfabrik). Four thicknesses (0.5, 1.0, 1.5 or 2.0 mm) of each indirect material were analyzed, and the light-activation was performed using a blue LED light. Data (n=5) were analyzed by three-way ANOVA, Tukey's post hoc and Dunnett's tests (a=5%). No significant differences in DC were observed between indirect materials of similar thickness. All groups exhibited higher DC after 10 min than after 5 min. At both times points, the self-cure group exhibited significantly lower DC than all the light exposure groups. Only when the overlying indirect restoration had a thickness of 2 mm did DC decrease significantly. The presence of a thick, indirect restoration can decrease the DC of resin cement. DC after 10 min was higher than after 5 min. The self-cure mode yielded lower DC than the light-activating one.

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Section: Introductionmentioning

confidence: 99%

Indirect Restoration Thickness and Time after Light-Activation Effects on Degree of Conversion of Resin Cement

et al. 2015

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“…However, as light passes through the bulk of the restorative material, its power density is greatly decreased due to the light absorption and scattering by dental composite resins, thus, decreasing the potential for polymerization [42,43].…”

Section: Discussionmentioning

confidence: 99%

Effect of different light-curing techniques on hardness of a microhybrid dental composite resin

Rastelli

Navarro

Saad

et al. 2014

BDS

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Objective: This study assessed the Vickers hardness provided by two LCUs when using (1) direct and indirect light-curing techniques, (2) 40 and 60 seconds and (3) top and bottom surfaces. Material and Methods: One halogen Curing Light 2500 (3M Espe) and one LED (MM Optics) were used by direct and indirect (0, 1.0, 2.0 and 3.0 mm of dental structure) techniques during 40 and 60 seconds. The samples were made with FiltekTM Z250 in a metallic mould with a central orifice (4 mm in diameter, 2 mm in thickness). The samples were stored in dry mean by ± 24 hours and the hardness measurements were performed in a testing machine (Buehler MMT-3 digital microhardness tester Lake Bluff, Illinois USA). A 50 gf load was used and the indenter with a dwell time of 30 seconds. The data were submitted to multiple ANOVA and Newman-Keuls‘s test (p<0.05). Results: Halogen LCU exhibited higher Vickers hardness values than LED mainly because of the power density used. Hardness values were influenced by LCUs, light-curing techniques, irradiation times and surfaces. For both LCUs, hardness values were found to decrease with indirect light-curing technique, mainly for the bottom surface. Samples irradiated for 60 s exhibited higher hardness values when the halogen LCU was used. For 60 seconds, the VHN values were statistically significant greater than 40 seconds. Significant differences in top and bottom surfaces Vickers hardness number (VHN) values were observed among different LCUs used 40 and 60 seconds. Conclusion: The LCUs, light-curing techniques, variations of irradiation times, and surfaces (top and bottom) influence the composite hardness. Keywords: Composite resin, LED, Halogen lamp, Hardness, Photo-activation.

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“…Since the introduction of bonding systems and composite resins, wear and microleakage were the primary clinical limitations, mainly in posterior restorations (1)(2)(3)(4)(5)(6)(7)(8). The relative porosity of the restorative and absorption/adsorption of oral fluids may also allow staining agents to penetrate the material (9).…”

Section: Introductionmentioning

confidence: 99%

Effect of different surface penetrating sealants on the roughness of a nanofiller composite resin

Lopes¹,

Saquy²,

Moura³

et al. 2012

Braz. Dent. J.

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This study evaluated the effectiveness of different sealants applied to a nanofiller composite resin. Forty specimens of Filtek Z-350 were obtained after inserting the material in a 6x3 mm stainless steel mold followed by light activation for 20 s. The groups were divided (n=10) according to the surface treatment applied: Control group (no surface treatment), Fortify, Fortify Plus and Biscover LV. The specimens were subjected to simulated toothbrushing using a 200 g load and 250 strokes/min to simulate 1 week, 1, 3 and 6 months and 1 and 3 years in the mouth, considering 10,000 cycles equivalent to 1 year of toothbrushing. Oral-B soft-bristle-tip toothbrush heads and Colgate Total dentifrice at a 1:2 water-dilution were used. After each simulated time, surface roughness was assessed in random triplicate readings. The data were submitted to two-way ANOVA and Tukey's test at a 95% confidence level. The specimens were observed under scanning electron microscopy (SEM) after each toothbrushing cycle. The control group was not significantly different (p>0.05) from the other groups, except for Fortify Plus (p<0.05), which was rougher. No significant differences (p>0.05) were observed at the 1-month assessment between the experimental and control groups. Fortify and Fortify Plus presented a rougher surface over time, differing from the baseline (p<0.05). Biscover LV did not differ (p>0.05) from the baseline at any time. None of the experimental groups showed a significantly better performance (p>0.05) than the control group at any time. SEM confirmed the differences found during the roughness testing. Surface penetrating sealants did not improve the roughness of nanofiller composite resin.

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Effect of thickness of indirect restoration and distance from the light-curing unit tip on the hardness of a dual-cured resin cement

Cited by 16 publications

References 15 publications

Indirect Restoration Thickness and Time after Light-Activation Effects on Degree of Conversion of Resin Cement

Indirect Restoration Thickness and Time after Light-Activation Effects on Degree of Conversion of Resin Cement

Effect of different light-curing techniques on hardness of a microhybrid dental composite resin

Effect of different surface penetrating sealants on the roughness of a nanofiller composite resin

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