Dental materials: official publication of the Academy of Dental Materials Journal Impact Factor & Information

Publisher: Elsevier

Journal description

Current impact factor: 4.16

Impact Factor Rankings

2015 Impact Factor Available summer 2015
2013 / 2014 Impact Factor 4.16
2012 Impact Factor 3.773
2011 Impact Factor 3.135
2010 Impact Factor 2.92
2009 Impact Factor 2.882
2008 Impact Factor 2.941
2007 Impact Factor 2.99
2006 Impact Factor 2.381
2005 Impact Factor 2.056
2004 Impact Factor 2.057
2003 Impact Factor 2.064
2002 Impact Factor 1.912
2001 Impact Factor 1.441
2000 Impact Factor 1.016
1999 Impact Factor 0.884
1998 Impact Factor 1.434
1997 Impact Factor 1.34
1996 Impact Factor 1.241
1995 Impact Factor 1.362
1994 Impact Factor 1.601
1993 Impact Factor 1.055
1992 Impact Factor 0.938

Impact factor over time

Impact factor
Year

Additional details

5-year impact 0.00
Cited half-life 5.50
Immediacy index 0.46
Eigenfactor 0.01
Article influence 0.80
ISSN 1879-0097

Publisher details

Elsevier

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    • Publisher last contacted on 18/10/2013
  • Classification
    ​ green

Publications in this journal

  • Dowon Ahn, Sameer S Sathe, Brian H Clarkson, Timothy F Scott
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    ABSTRACT: The aim of this study is to determine if hexaarylbiimidazoles (HABIs) are efficient, visible light-active photoinitiators for thiol-ene systems. We hypothesize that, owing to the reactivity of lophyl radicals with thiols and the necessarily high concentration of thiol in thiol-ene formulations, HABIs will effectively initiate thiol-ene polymerization upon visible light irradiation. UV-vis absorption spectra of photoinitiator solutions were obtained using UV-vis spectroscopy, while EPR spectroscopy was used to confirm radical species generation upon HABI photolysis. Functional group conversions during photopolymerization were monitored using FTIR spectroscopy, and thermomechanical properties were determined using dynamic mechanical analysis. The HABI derivatives investigated exhibit less absorptivity than camphorquinone at 469nm; however, they afford increased sensitivity at this wavelength when compared with bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide. Photolysis of the investigated HABIs affords lophyl radicals. Affixing hydroxyhexyl functional groups to the HABI core significantly improved solubility. Thiol-ene resins formulated with HABI photoinitiators polymerized rapidly upon irradiation with 469nm. The glass transition temperatures of the thiol-ene resin formulated with a bis(hydroxyhexyl)-functionalized HABI and photopolymerized at room and body temperature were 49.5±0.5°C and 52.2±0.1°C, respectively. Although thiol-enes show promise as continuous phases for composite dental restorative materials, they show poor reactivity with the conventional camphorquinone/tertiary amine photoinitiation system. Conversely, despite their relatively low visible light absorptivity, HABI photoinitiators afford rapid thiol-ene photopolymerization rates. Moreover, minor structural modifications suggest pathways for improved HABI solubility and visible light absorption. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 06/2015; DOI:10.1016/j.dental.2015.06.005
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    ABSTRACT: This study evaluated how the flexural strength and fracture behavior of a zirconia-based ceramic (Y-TZP) were affected by pre- and post-sintering mechanical and thermal treatments. Treatments included sandblasting with different particle size and type (30μm SiO2; 50 and 110μm Al2O3) and thermal conditioning. Two hundred bar-shaped specimens of pre-sintered Y-TZP ceramic (Lava Frame, 3M) were prepared (specimen dimensions: 25mm length×4mm width×0.7mm thickness) and divided into three groups (before sintering, after sintering and after sintering with heating treatment). The before sintering group specimens were airborne-particle abraded prior to dense sintering. Specimens from the after sintering group were airborne-particle abraded after sintering. The after sintering with heating treatment group specimens were submitted to a heating procedure after airborne-particle abrasion. The controls were the specimens that were sintered and not treated with any conditioning procedures. The specimens from all experimental conditions were analyzed by SEM, CLSM and XRD. All specimens were tested in four-point bending. Data were statistically analyzed using one-way ANOVA and Post Hoc tests (α=0.05). A Weibull analysis was used to analyze the strength reliability. Sandblasting pre-sintered zirconia before sintering significantly decreased the flexural strength, except when the smallest blasting particles were used (30μm SiO2). Phase transformation (t-m) was observed after sandblasting and reverse transformation (m-t) was observed after heating. Sandblasting with 30μm SiO2 and 50μm Al2O3 allowed lower phase transformation. However, 30mm SiO2 presented better reliability. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 06/2015; DOI:10.1016/j.dental.2015.05.008
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    ABSTRACT: This study reports on the synthesis, materials characterization, antimicrobial capacity, and cytocompatibility of novel ZnO-loaded membranes for guided tissue/bone regeneration (GTR/GBR). Poly(ɛ-caprolactone) (PCL) and PCL/gelatin (PCL/GEL) were dissolved in hexafluoropropanol and loaded with ZnO at distinct concentrations: 0 (control), 5, 15, and 30wt.%. Electrospinning was performed using optimized parameters and the fibers were characterized via scanning and transmission electron microscopies (SEM/TEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), contact angle (CA), mechanical testing, antimicrobial activity against periodontopathogens, and cytotoxicity test using human dental pulp stem cells (hDPSCs). Data were analyzed using ANOVA and Tukey (α=5%). ZnO nanoparticles were successfully incorporated into the overall submicron fibers, which showed fairly good morphology and microstructure. Upon ZnO nanoparticles' incorporation, the PCL and PCL/GEL fibers became thicker and thinner, respectively. All GEL-containing membranes showed lower CA than the PCL-based membranes, which were highly hydrophobic. Overall, the mechanical properties of the membranes were reduced upon ZnO incorporation, except for PCL-based membranes containing ZnO at the 30wt.% concentration. The presence of GEL enhanced the stretching ability of membranes under wet conditions. All ZnO-containing membranes displayed antibacterial activity against the bacteria tested, which was generally more pronounced with increased ZnO content. All membranes synthesized in this study demonstrated satisfactory cytocompatibility, although the presence of 30wt.% ZnO led to decreased viability. Collectively, this study suggests that PCL- and PCL/GEL-based membranes containing a low content of ZnO nanoparticles can potentially function as a biologically safe antimicrobial GTR/GBR membrane. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 06/2015; DOI:10.1016/j.dental.2015.06.004
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    ABSTRACT: This study evaluated the microtensile bond strength (μTBS) and nanoleakage (NL) of dentin bonded interfaces produced with ethanol-wet and water-wet bonding protocols under clinical and laboratory conditions. The sample was composed of forty primary second molars in advanced exfoliation process. Occlusal cavities were prepared leaving a flat dentin surface on the pulpal floor. In half of the teeth, the water-wet protocol was followed using a three-step etch-and-rinse adhesive. In the other half, dentin was dehydrated with ascending ethanol solutions (50%, 70%, 80%, 95% and 3×100%), 15s each for the ethanol-bonding protocol. An experimental hydrophobic primer was used, followed by the neat adhesive application. Resin build-ups were prepared, stored for 24h, sectioned into sticks and tested in tensile mode (0.5mm/min). NL was performed for all groups. The μTBS and NL data were submitted to two-way ANOVA and Kruskall-Wallis tests, respectively (α=0.05). Under clinical conditions, the highest μTBS was observed for the water-wet bonding while under the laboratory setting, the highest μTBS was obtained for the ethanol-wet bonding. Increased NL was observed in the water-wet bonding groups irrespective of the bonding condition. The immediate benefits of the ethanol-bonding observed in the laboratory setting was not confirmed when the same protocol was performed in vivo. However, as reduced nanoleakage was seen in adhesive interfaces produced with the ethanol-wet bonding technique, suggests that the hybrid layer may be more resistant to degradation. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 06/2015; DOI:10.1016/j.dental.2015.05.010
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    ABSTRACT: Poor interfacial adhesion between the fibers and resin matrix in the ultra high molecular weight polyethylene (UHMWPE) fiber reinforced composites (FRCs) is the main drawback of the composites. This study aims to evaluate the effect of corona and silane surface treatment of the fibers on the mechanical properties of the UHMWPE FRCs. UHMWPE fibers were exposed to corona discharges for different periods of time (0s, 5s, 7s). The surface characteristics of the UHMWPE fibers were investigated by attenuated total reflectance Fourier transformed infrared spectroscopy (ATR-FTIR), atomic force microscopy (AFM), scanning electron microscopy (SEM) and nanoindentation technique. The flexural strength and flexural modulus of the FRCs made of the treated fibers were determined on 2mm×2mm×25mm specimens. The fracture toughness (the critical stress intensity factor, KIC) of the composites was also evaluated using a three-point single edge notch beam (SENB) bending technique. Statistical analysis of the data was performed with ANOVA and the Tukey's post-hoc test. The fiber-resin interface and the fracture surface were investigated using SEM. The change in the surface mechanical properties and chemistry of the corona treated UHMWPE fibers were monitored. The fibers exposed to corona for 5s showed higher surface nanohardness. In the FRCs, the specimens reinforced with 5s corona treated silanized fibers showed higher mechanical properties (flexural modulus, flexural strength, and fracture toughness), SEM images revealed a better adhesion between the resin and fibers after 5s fiber corona treatment and silanization. Corona and silane treatment of UHMWPE fibers provide dental FRCs with improved mechanical properties. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 06/2015; DOI:10.1016/j.dental.2015.05.011
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    ABSTRACT: The aim of this study is to analyze the survival of posterior composite restorations published within the last 19 years (1996-2015). In this study only prospective, clinical trials with specification of the failure rate according to Class I/II composite fillings were included. Studies were analyzed according to the observation period (all studies vs. short-term vs. long-term studies). Retrospective studies and/or open laminate studies, tunnel restorations and Class V restorations were excluded. The following variables possibly influencing the failure rate were extracted from the studies: observation period, recall rate, average age of patients, number of patients, ratio of Class I/II fillings, number of restorations, ratio of premolars/molars, operator, method of isolation, bonding generation and filler size. A total of 88 studies were included for statistical analysis. The observation period of the studies varied between 1 and 17 years, while most of the studies did not last longer than 5 years. Fracture of the restorations, secondary caries and marginal gap are the main causes for failure in the first 5 years (in descending order), while fracture and secondary caries are similarly distributed in long-term studies. Variables of investigation differed greatly in significance according to the respective observation period. The observation period, the recall rate, the ratio of Class I/II fillings and the number of restorations and patients had a significant influence on the overall failure rate when including all studies (short- and long-term). A linear correlation between the observation period and the failure rate was observed. In long-term studies these variables were not significant any longer. No significant difference in the failure rates between the materials per study was observed. The most common commercial composites investigated were: Tetric Ceram, Surefil, Filtek Supreme (incl. XT), Filtek Z250. The mean annual failure rate was 1.46% (±1.74%) for short-term studies and 1.97% (±1.53) for long-term studies. There is still a big need for clinical studies lasting longer than 5 years, as failure rates of composite restorations in posterior teeth increases with longer observation periods. A decreasing failure rate with an increasing recall rate as observed in our study suggests a patient selection in regard to availability and dental awareness. Internationally standardized evaluation criteria are mandatory in order to allow comparisons of the outcomes of clinical studies. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 06/2015; DOI:10.1016/j.dental.2015.05.004
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    ABSTRACT: Elucidating the microstructural responses of the lithium disilicate system like the popular IPS e.max® CAD (LS2), made specifically for computer-aided design and computer-aided manufacturing (CAD-CAM), as a temperature-dependent system unravels new ways to enhance material properties and performance. To study the effect of various thermal processing on the crystallization kinetics, crystallite microstructure, and strength of LS2. The control group of the LS2 samples was heated using the standard manufacturer heating-schedule. Two experimental groups were tested: (1) an extended temperature range (750-840°C vs. 820-840°C) at the segment of 30°C/min heating rate, and (2) a protracted holding time (14min vs. 7min) at the isothermal temperature of 840°C. Five other groups of different heating schedules with lower-targeted temperatures were evaluated to investigate the microstructural changes. For each group, the crystalline phases and morphologies were measured by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. Differential scanning calorimeter (DSC) was used to determine the activation energy of LS2 under non-isothermal conditions. A universal testing machine was used to measure 3-point flexural strength and fracture toughness, and elastic modulus and hardness were measured by a nanoindenter. A one-way ANOVA/Tukey was performed per property (alpha=0.05). DSC, XRD, and SEM revealed three distinct microstructures during LS2 crystallization. Significant differences were found between the control group, the two aforementioned experimental groups, and the five lower-targeted-temperature groups per property (p<0.05). The activation energy for lithium disilicate growth was 667 (±29.0)kJ/mol. Groups with the extended temperature range (750-840°C) and protracted holding time (820-840°C H14) produced significantly higher elastic-modulus and hardness properties than the control group but showed similar flexural-strength and fracture-toughness properties with the control group. In general, rapid growth of lithium disilicates occurred only when maximum formation of lithium metasilicates had ended. Published by Elsevier Ltd.
    Dental materials: official publication of the Academy of Dental Materials 06/2015; DOI:10.1016/j.dental.2015.05.003
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    ABSTRACT: The aim of this study was to investigate antibiofilm effects of a recently developed glass ionomer cement (GIC) containing dimethylaminododecyl methacrylate (DMADDM) under oral conditions. Biofilms were allowed to form in situ on GIC specimens (n=216) which contained DMADDM (1.1wt.% or 2.2wt.%). Samples without DMADDM served as control (n=108). GIC specimens were fixed on custom made splints and exposed to the oral cavity in six healthy volunteers for 24, 48 and 72h, respectively. Biofilm viability and coverage were analyzed by fluorescence microscopy (FM) and evaluated by red/green ratios and an established scoring system. Bacterial morphology and biofilm accumulation were determined by scanning electron microscopy (SEM). Additionally, material properties as surface charge density of quaternary ammonium groups, surface roughness and DMADDM release were recorded. FM results showed a higher ratio (24h: 0%: 0.5, 1.1%: 1.2, 2.2%: 2.5) of red/green fluorescence on GIC samples containing DMADDM. Biofilm coverage and viability scores were significantly reduced (24h: q1/median/q3 for: 0%: 3/4/5, 1.1%: 2/3/3, 2.2%: 1/2/2) on DMADDM containing samples compared to controls after 24h as well as 48 and 72h in situ (p<0.05). While surface charge density of quaternary ammonium groups and DMADDM release increased with the DMADDM concentration, surface roughness was lowest on specimens containing 2.2wt.% DMADDM. An in situ dental biofilm model was used to evaluate the novel GIC containing DMADDM. This material strongly inhibited biofilms in situ and is promising to prevent bacterial colonization on the surface of restorations. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 06/2015; DOI:10.1016/j.dental.2015.05.005
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    ABSTRACT: The Schwickerath three point bending adhesion test is the basis of the International Standard ISO 9693:1999 procedure for assessing porcelain bonding to metals [1]. It has also been used to evaluate the adhesion of porcelain to zirconia. The purpose of this paper is a fracture mechanics analysis of this test, which allows determination of the crack-length load-displacement and toughness dependence of cracks extending along or near the interface. Linear elastic mechanics is used to develop expressions for the strain energy and compliance of Schwickerath geometry specimens as a function of crack extension along or near the interface. From the derivative of the compliance as a function of crack growth the strain energy release rate (G, N/m) is determined. The energy release rate for interface crack extension of Schwickerath geometry specimens is determined. It is found that a simple relationship between the minima of the force-displacement response and the strain energy release rate G exists. Further development enables the predicted force-displacement response as a function of crack length to be derived for different values of G. Experimental results of porcelain bonded to zirconia with and without notches of various lengths machined along the interface verify the expressions and analysis developed. With the fracture mechanics analysis developed in this paper it is possible to determine the quality of adhesion in Schwickerath specimens by the interface toughness in addition to the nominal interface shear bond strength. As the toughness of brittle materials has much less scatter than its strength, the interface toughness characterization of the adhesion should allow for a better distinction between the adhesion quality of bonding. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 06/2015; DOI:10.1016/j.dental.2015.05.007
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    ABSTRACT: The present study evaluated the effect of the coefficient of thermal expansion (CTE) mismatch and the cooling protocol on the distribution of residual stresses and crack propagation in veneered zirconia bilayers. Ceramic discs with two different CTEs (Vita VM9 and Lava Ceram) were fired onto zirconia plates and cooled following a slow (0.5°C/s) or a fast (45°C/s) cooling protocol. The residual stress distribution throughout the veneer thickness was assessed by means of depth-wise Vickers indentation after sequentially sectioning the bilayers parallel compared to normal to the interface. A mathematical solution for the residual stress distribution was used as reference. Additionally, Hertzian cone crack propagation in the veneers was induced by cyclic contact loading and measured at different number of cycles to estimate the crack growth rate. The higher CTE mismatch of the VM9 group generated an important stress gradient with high compressive residual stresses near the interface, hindering the crack propagation. The low CTE mismatch group (Lava Ceram) developed only a slight stress gradient and higher cone crack growth rates. No differences were observed between the two cooling protocols applied regarding stress magnitude and crack propagation behavior. The CTE mismatch has a predominant role in the generation of residual stress gradients within the veneer, which directly influences contact-induced crack propagation. Based on the results, the cooling protocol had no significant effect on the residual stress distribution in zirconia-veneer bilayers. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 05/2015; DOI:10.1016/j.dental.2015.05.001
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    ABSTRACT: Residual unbound resin monomers of 2-hydroxyethyl methacrylate (HEMA) and triethylene glycol dimethacrylate (TEGDMA) are known to diffuse in the saliva and through dentin and pulp into the blood and may affect cellular integrity. The current study was performed to investigate the genotoxic potential of both monomers in distinctly lower concentrations than known to cause cytotoxic damage. Lymphocytes from 10 healthy volunteers were treated with HEMA (10μM-1mM) and TEGDMA (1μM-100μM) for 24h. Cell viability, apoptosis and influence on cell cycle kinetics were assessed by flowcytometry. DNA damage was determined by the alkali version of the comet assay in combination with the FPG protein and by the cytokinesis-block micronucleus (CBMN) test. Additionally, the chromosome aberration (CA) test and sister chromatid exchange (SCE) test were performed. A slight decrease in cell viability was detected only at the highest concentration of TEGDMA. Genotoxic effects were measurable in the comet assay at 1mM of HEMA and 100μM of TEGDMA, with and without FPG protein, but not in the CBMN test or the cell cycle analysis. Contrary to these findings, a significant dose-dependent increase in the frequency of CAs and SCEs could be demonstrated in all tested concentrations. This is the first time clastogenic responses to HEMA and TEGDMA have been detected in concentrations distinctly lower than those reported for causing cytotoxic or even genotoxic effects. These findings underline the importance of using test batteries with different genotoxicological endpoints to describe the multiple effects of both resin monomers. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 05/2015; DOI:10.1016/j.dental.2015.04.009
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    ABSTRACT: This study tested whether treatment of demineralized dentin with polyacrylic acid (PAA) has any activatory or inhibitory activity on dentin matrix metalloproteinases (MMP)s or cathepsin K (CAT-K). Dentin beams (1mm×2mm×6mm; n=10) were completely demineralized with EDTA. After initial dry mass assessment, the beams were dipped into 37% phosphoric acid (PA), PA+2% benzalkonium chloride (BAC), PA+2% chlorhexidine digluconate (CHX), 10% PAA, PAA+BAC or PAA+CHX for 20s. Demineralized beams without treatment served as control. All beams were incubated in simulated body fluid (SBF) for 1 week and the dry mass loss was evaluated. Aliquots of SBF were used to analyze solubilized telopeptide fragments using ICTP as indicator of MMP-mediated collagen degradation and CTX for CAT-K-mediated degradation. Additional demineralized beams (n=10) were used to measure the influence of different chemical treatments on total MMP activity of EDTA-demineralized dentin using generic MMP assay. Data were analyzed by ANOVA (α=0.05). Dry mass loss ranged from 6% (PA) to 2% for (PA-BAC) or (PAA-BAC) (p<0.05). ICTP release of PAA-treated group was significantly higher (p<0.05) than the control, and not significantly different from the PA group (p>0.05). PA+CHX or PAA+CHX and PAA+BAC showed significantly lower ICTP than PA or PAA groups (p<0.05). CAT-K activity increased significantly after 10% PAA treatment compared to control (p<0.05) or to PA postreatment. Demineralized dentin treated with 10% polyacrylic acid activated CAT-K more than 37% phosphoric acid; 2% chlorhexidine digluconate seems to be a better inhibitor of MMPs and CAT-K than 2% benzalkonium chloride. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 05/2015; DOI:10.1016/j.dental.2015.04.018
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    ABSTRACT: To investigate the single-edge notched (SEN) bend fracture toughness (KIC) testing methodology as a reproducible and discriminatory mechanical testing protocol for encapsulated and hand-mixed glass-ionomers (GI). SEN bend test-pieces (35.0±0.1mm length, 6.0±0.1mm width, 3.0±0.1mm thickness with a sharp notch formed at mid-length by embedding a scalpel blade) were prepared for KIC testing using three encapsulated GI products (Chemfil Rock, Fuji IXGP Fast Capsule and Ionofil Molar AC). In addition, test-pieces were prepared from a hand-mixed GI product (Ionofil Molar) which contained between 100% and 20% of the manufacturer's recommended powder content (in 10% decrements) for a constant weight of liquid. Groups of 20 test-pieces were prepared for each encapsulated GI product (n=3) and hand-mixed GI powder:liquid mixing ratio (n=9). Data were statistically analyzed and the coefficients of variation (CoV) determined for each encapsulated GI product and hand-mixed GI powder:liquid mixing ratio. The KIC testing methodology failed to discriminate between the encapsulated GI products that were investigated (p=0.225). For the hand-mixed GI, the KIC testing methodology also failed to discriminate between the powder:liquid mixing ratios investigated (R(2)=0.576). The pooled CoV (10%) for the encapsulated GI products and for the powder:liquid mixing ratio groups (12%) identified the reproducibility of the test for this experiment. For the hand-mixed GI mixing ratio groups with between 100% to 50% of the recommended powder content, no trend could be discerned. The KIC testing methodology failed to discriminate between different encapsulated GI products and hand-mixed GI powder:liquid mixing ratio groups investigated, despite KIC being an intrinsic material property and the coefficient of variation being acceptable. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 05/2015; DOI:10.1016/j.dental.2015.04.014
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    ABSTRACT: to evaluate the influence of the occlusal resin cement thickness on the cyclic loads-to-failure of feldspathic crowns and to compare the results to data from monotonic tests. A large range of cement thickness (50μm and 500μm) was tested, in order to better measure the influence of this variable. Feldspathic ceramic crowns (Vita Mark II blocks, Vita Zahnfabrik) were bonded to dentin analog dies (G10 (NEMA grade G10, International Paper), with occlusal resin cement thicknesses of 50μm and 500μm (Multilink Automix, Ivoclar). The dies were prepared with microchannels for water transport to the cement layer. After 96-h water storage, the specimens (n=20) were submitted to cyclic loads (500,000 cycles at 20Hz; initial maximum load=40% of monotonic load, from previous data) following a staircase sensitivity design (step size=25N). Failure loads at 500,000 cycles were compared to monotonic failure loads (from a previous study with specimens produced by the same author, using the same materials, specimen configuration and cementation protocol). Crowns with an occlusal cement layer of 50μm were more resistant than those cemented with 500μm (246.4±22.9N vs. 158.9±22.9N), under wet cyclic testing conditions (p<0.001). The fatigue failure loads were reduced compared to monotonic loads: to 37% of monotonic for 50μm; to 53% of monotonic for 500μm. An occlusal cement thickness of 50μm was more favorable for the structural performance of feldspathic crowns than was 500μm. Cyclic fatigue reduced failure loads well below those found under monotonic loading. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
    Dental materials: official publication of the Academy of Dental Materials 05/2015; DOI:10.1016/j.dental.2015.04.019