bluuebunny/crossref_metadata_2025_split huggingface dataset:
Contrast Ratio of Six Zirconia‐Based Dental Ceramics
Authors: Kanchanavasita Widchaya , Triwatana Premwara , Suputtamongkol Kallaya , Thanapitak Alisa , Chatchaiganan Mathura 
Published: April 2014

AbstractPurposeThe objective of this study was to determine the effect of thickness and brands on the contrast ratio of six zirconia dental ceramics.Materials and MethodsSix brands of yttria‐stabilized tetragonal zirconia polycrystalline (Y‐TZP) ceramics (ZENO® Translucent, Lava™ Plus High Translucency, inCoris TZI, Cercon® Base, Zeno®Zr, Lava™) were used in this study. Disc‐shaped specimens with 15 mm diameter were prepared in five thickness levels (0.3, 0.6, 0.9, 1.2, 1.5 mm, n = 10) for each brand. The contrast ratio (CR = Yb/Yw) was determined from the luminous reflectance over black (Yb) and white (Yw) backgrounds using a spectrophotometer. Two‐way ANOVA was performed to determine the significant differences among thicknesses and brands at α = 0.05.ResultsThe mean contrast ratio values of six zirconia ceramics were significantly different and influenced by both the thickness and brand. The mean contrast ratio values of all groups increased as their thickness increased from 0.3 to 1.5 mm. inCoris TZI was the most translucent, with the lowest contrast ratio at a thickness of 0.6 to 1.5 mm. The mean contrast ratio values of Lava™ and Lava™ Plus were significantly lower than those of Zeno®Zr, ZENO® Translucent, and Cercon® Base.ConclusionsThe thickness and brands had significant effects on the contrast ratio of six zirconia dental ceramics. The mean contrast ratio values of inCoris TZI, Lava™, and Lava™ Plus High Translucency were significantly lower than those of Cercon® Base, Zeno®, and ZENO® Translucent at all thicknesses.
Improvement in Dental Porcelain Bonding to Milled, Noncast Titanium Surfaces by Gold Sputter Coating
Authors: Lin Mau‐Chin , Huang Her‐Hsiung 
Published: April 2014

AbstractPurposeThis study evaluated the adherence of dental porcelain to a milled, noncast titanium (Ti) surface with a gold sputter coating to evaluate a possible new practical surface treatment for enhancing the bond strength between Ti and porcelain.Materials and MethodsMilled, noncast Ti strips were created by computer‐aided design and manufacturing processes. The milled, noncast Ti strips were sandblasted with alumina particles and were then sequentially subjected to gold sputter coating treatments of 150‐ and 300‐second duration. Low‐fusion dental porcelain was then sintered onto the surface‐treated Ti strips. The bond strengths of the Ti/porcelain specimens were evaluated using a three‐point bending test (ISO 9693). Surface characterizations of the specimens were carried out with X‐ray photoelectron spectrometry, scanning electron microscopy, and energy dispersive X‐ray spectroscopy.ResultsThe results indicated that the bond strengths of all the Ti/porcelain groups were greater than the minimum requirement (25 MPa) as prescribed by ISO 9693. The gold sputter coating increased the oxidation resistance (or decreased the oxide content) of the Ti surface during porcelain sintering, which positively affected the bond strength of Ti/porcelain (approximately 36 MPa) compared to the untreated Ti/porcelain specimen (approximately 29 MPa). The fracture morphologies of all the Ti/porcelain groups revealed an adhesive bond failure as the interfacial fracture mode between the Ti and the porcelain.ConclusionsA practical and simple sandblasting/gold sputter coating treatment of Ti surfaces prior to porcelain sintering significantly strengthens the bond between the milled, noncast Ti and the dental porcelain.
The Effect of Glass Fiber‐Reinforced Epoxy Resin Dowel Diameter on the Fracture Resistance of Endodontically Treated Teeth
Authors: Tey Kuan Chuan , Lui Joo Loon 
Published: April 2014

AbstractPurposeTo determine the effect of glass fiber‐reinforced epoxy resin (FRC) dowels of different diameters on the failure load of endodontically treated teeth with different remaining dentine and reinforcing resin composite (RRC) thicknesses and the mode of failure in each group.Materials and MethodsFifty extracted intact human maxillary central incisors were decoronated 2 mm incisal to the buccal cementoenamel junction and endodontically treated. The teeth were randomly assigned to one of five groups (n = 10): group B, dowel space prepared with size 0 dowel drill/size 0 FRC dowel/no RRC; group W, size 1 dowel space/size 1 FRC dowel/no RRC; group R, size 3 dowel space/size 3 FRC dowel/no RRC; group WR, size 3 dowel space/size 1 FRC dowel/RRC; group BR, size 3 dowel space/size 0 FRC dowel/RRC. Ferrules of 2 and 0.5 mm were prepared at the facio‐lingual and proximal margin respectively. All specimens were restored with a Ni‐Cr crown, thermocycled and loaded at 135° from the long axis in a universal testing machine at a 0.5 mm/min crosshead speed until fracture. Data were analyzed using ANOVA followed by post hoc comparisons (Bonferroni) with α = 0.05.ResultsMean failure loads (N) for groups B, W, R, WR, and BR were as follows: 1406 (SD = 376), 1259 (379), 1085 (528), 959 (200), and 816 (298). Significant differences were found between groups B and BR. Group B had the highest favorable failure mode.ConclusionWithin the limitations of this study, the use of a smaller FRC dowel and RRC is recommended rather than enlargement of dowel spaces to accurately fit larger FRC dowels, as the enlargement of dowel space may increase the risk of unfavorable failure.
A Novel Coping Design to Decrease Maximum Principal Stress in Zirconia Ceramic Restorations
Authors: Sung MooGyung , Han Chong‐Hyun , Kim Sunjai 
Published: April 2014

AbstractPurposeThe objective of this study was to evaluate the influence of coping design modifications on maximum first principal stress (MPS) in a mathematical zirconia ceramic crown model.Materials and MethodsFor a nonlinear, 3D finite element analysis, a simplified tooth model was built on the basis of the average dimensions of mandibular second molars. Virtual tooth reduction was performed to model an abutment with a flat occlusal surface and 16° convergence angle between facing walls. The cement layer was set to a thickness of 100 μm. Three different copings—one with 0.5‐mm constant thickness; one with constant thickness and extended lingual and proximal collars; and a novel design with zirconia beam reinforcement—were designed to simulate zirconia ceramic restorations. The novel design had strategically positioned zirconia beams on the lingual and marginal ridges to protect veneer ceramics, and was divided into three subdesigns according to the width of the zirconia beam (0.5, 0.8, and 1 mm). Combinations of vertical and horizontal load were applied over the distolingual marginal ridge, and the MPSs were evaluated.ResultsThe novel design showed the lowest MPS in veneer ceramics under most loading conditions. The only exception to this was the novel design with a 0.5‐mm zirconia beam width under mesial horizontal load.ConclusionsCompared to constant thickness coping with or without extended collars, the novel coping design reduced MPS in veneer ceramics; however, narrow zirconia beams should be avoided to prevent elevations in MPS in veneer ceramic layers.
Prosthetic Improvement of Pronounced Buccally Positioned Zygomatic Implants: A Clinical Report
Authors: Bacchi Ataís , dos Santos Mateus Bertolini Fernandes , Pimentel Marcele Jardim , Nóbilo Mauro Antonio de Arruda , Consani Rafael Leonardo Xediek 
Published: April 2014

AbstractThis report presents a prosthetic technique for the improvement of surgically positioned, buccally placed zygomatic implants with the use of custom abutments for improved retention screw position and an esthetic implant reconstruction. The patient presented four zygomatic implants with pronounced buccal inclination. The anterior implants were inclined toward the location where the anterior artificial teeth should be placed during rehabilitation. As the manufacturer does not provide angulated abutments, we attempted the waxing and overcasting of a prosthetic abutment, repositioning the access holes of the prosthetic screws to a more palatal position. This clinical report demonstrates that abutment customization could be an interesting way to relocate the access holes of the prosthetic screws in cases of zygomatic implants with pronounced buccal inclination.
Electrochemical Corrosion and Surface Analyses of a Ni‐Cr Alloy in Bleaching Agents
Authors: Tamam Evşen , Aydın A. Kevser , Bilgiç Semra 
Published: April 2014

AbstractPurposeThe aim of this study was to evaluate the corrosion behavior of a Ni‐Cr dental casting alloy subjected to 10% hydrogen peroxide (HP) and 10% carbamide peroxide (CP) bleaching solutions and to determine the composition of the surface oxide layer formed on the alloy specimens.Materials and MethodsTen cylindrical specimens (4 mm in diameter × 25 mm in height) were cast from a Ni‐Cr alloy (Wiron 99) and divided into two groups (n = 5). A potentiodynamic polarization test was used to compare the corrosion rates of specimens in HP and CP (pH = 6.5). Before cyclic polarization tests, all alloy specimens were allowed to reach a steady open circuit potential (Ecorr) for a period of 1 hour. Then tests were initiated at 100 mV versus standard calomel electrode (SCE) below Ecorr and scanned at a rate of 1 mV/s in the anodic direction until reaching 1000 mV over the Ecorr value. The scan then was reversed back to the Ecorr of the specimens. The open circuit potentials (Ecorr) and the current densities (Icorr) were determined using the anodic Tafel regions extrapolating from the curves. Differences in Ecorr and Icorr were determined using one‐way ANOVA (α = 0.05). In addition, corrosion rates were calculated from these curves. Before and after polarization tests, a scanning electron microscope (SEM) examination accompanied by energy dispersive X‐ray spectroscopy (EDS) was used to analyze the surface morphology. The surface characterization of the passive film formed on alloy specimens was also performed by using X‐ray photoelectron spectroscopy (XPS).ResultsIn this study, bleaching agents had an effect on the anodic process for two groups. Although no statistical difference was identified between the groups for both corrosion parameters, results indicated that the effect of CP on the corrosion behavior was less than that of HP. These results agreed with the SEM observations. XPS data showed that oxide layers formed on all groups contained mainly Cr2O3, NiO, and MoO3, and the amounts of oxides formed on CP‐treated specimens were higher than HP treated ones. Also, molybdenum rates were increased with CP application compared to HP.ConclusionsThe comparison of the effects of the two bleaching agents at 10% showed that the alloy suffered less corrosion with CP than HP. This result was also confirmed by the SEM and XPS data. The presence of Mo on the oxide layer affected the oxide layer, leading to lower corrosion rates
Influence of Implant/Abutment Connection on Stress Distribution to Implant‐Surrounding Bone: A Finite Element Analysis
Authors: Hanaoka Marcia , Gehrke Sergio Alexandre , Mardegan Fabio , Gennari César Roberto , Taschieri Silvio , Del Fabbro Massimo , Corbella Stefano 
Published: April 2014

AbstractPurposeThe objective of this study was to analyze and compare the stress distribution in the cortical and trabecular bone between the internal hexagon and the Morse taper systems, both with straight abutments.Materials and MethodsTwo implant systems (Morse taper and internal hexagon connections) were simulated in maxillary bone. Loads of 100 N (axial) and 50 N (oblique) in relation to the implant axes were applied. The 3D finite element method was used to simulate and analyze the present study. The analyzed parameters were ultimate tensile strength and Von Mises stress.ResultsBoth systems presented stresses below the bone tissue physiological limit as well as a similar distribution in quantitative values, with a higher concentration of tension in the cortical surface near the neck of the implant in the two conditions of applied loads, with higher values for the internal hexagon system. When the groups were evaluated individually, the internal hexagon system showed higher compressive stresses, while in the Morse taper system, the highest values were traction.ConclusionsThere was a difference in the stress location on the prosthetic components of the systems studied; however, it did not influence trabecular bone stress generation.
Effect of Beverages and Mouthwashes on the Hardness of Polymers Used in Intraoral Prostheses
Authors: Goiato Marcelo Coelho , dos Santos Daniela Micheline , Andreotti Agda Marobo , Nobrega Adhara Smith , Moreno Amalia , Haddad Marcela Filié , Pesqueira Aldiéris Alves 
Published: April 2014

AbstractPurposeThe mechanical properties of acrylic resins used in intraoral prostheses may be altered by frequent exposure to liquids such as beverages and mouthwashes. This study aimed to evaluate the effect of thermocycling and liquid immersion on the hardness of four brands of acrylic resins commonly used in removable prostheses (Onda Cryl, QC‐20, Clássico, Lucitone).Materials and MethodsFor each brand of resin, seven specimens were immersed in each of six solutions (coffee, cola, red wine, Plax‐Colgate, Listerine [LI], Oral B), and seven more were placed in artificial saliva (control). The hardness was tested using a microhardness tester before and after 5000 thermocycles and after 1, 3, 24, 48, and 96 hours of immersion. The results were analyzed using three‐way repeated‐measures ANOVA and Tukey's test (p < 0.05).ResultsThe hardness of the resins decreased following thermocycling and immersion in the solutions. Specimens immersed in cola and wine exhibited significant decreases in hardness after immersion for 96 hours, although the greatest significant decrease in hardness occurred in specimens immersed in LI. However, according to American Dental Association specification 12, the Knoop hardness of acrylic resins for intraoral prostheses should not be below 15. Thus, the median values of superficial hardness observed in most of the acrylic resins in this study are considered clinically acceptable.ConclusionsThe microhardness of polymers used for intraoral prostheses decreases following thermocycling. Among specimens immersed in beverages, those immersed in cola or wine experienced the greatest decrease in microhardness. Immersion of acrylic resins in LI significantly decreased the microhardness in relation to the initial value. Among the resins assessed, QC‐20 exhibited the lowest initial hardness.
Survival and Complication Rates of Fixed Restorations Supported by Locking‐Taper Implants: A Prospective Study with 1 to 10 Years of Follow‐Up
Authors: Mangano Francesco , Macchi Aldo , Caprioglio Alberto , Sammons Rachel Lilian , Piattelli Adriano , Mangano Carlo 
Published: April 2014

AbstractPurposeThe aim of this 10‐year follow‐up study was to evaluate the implant survival and complication rates of fixed restorations supported by locking‐taper implants.Materials and MethodsOver a 10‐year period (January 2002 to December 2011) all patients referred to a single private practice for treatment with fixed restorations (single crowns, SCs; fixed partial prostheses, FPPs; fixed full arches, FFAs) supported by dental implants were considered for inclusion in the study. At each annual follow‐up session, clinical, radiographic, and prosthetic parameters were assessed. The surviving implant‐supported restorations were defined as “complication free” in the absence of any biological or prosthetic (mechanical or technical) complication. The cumulative implant survival and the “complication‐free” survival of fixed implant‐supported restorations were identified using the Kaplan‐Meier method. The Log‐rank test was used to identify correlations between the study variables.ResultsIn total, 1494 locking‐taper implants (727 maxilla, 767 mandible) were placed in 642 patients (356 males, 286 females). Nineteen implants (12 maxilla, 7 mandible) failed. Implant failures were attributed to lack of osseointegration (14 implants), peri‐implantitis (4 implants), and mechanical overloading (1 implant). An overall 10‐year cumulative implant survival rate of 98.7% (98.3% maxilla, 99.1% mandible) was found. The implant survival rates did not significantly differ with respect to implant location, position, bone type, implant length and diameter, and type of restorations. Among the surviving implant‐supported restorations (478 SC, 242 FPP, 19 FFA), a few biological (11/739: 1.4%) and prosthetic (27/739: 3.6%) complications were reported. The incidence of mechanical complications was low (3/739: 0.4%), with three loosened abutments in three SCs (3/478: 0.6%), and no abutment fractures; technical complications were more frequent (24/739: 3.2%), with an incidence of decementation of 2.0% (SC 2.0%, FPP 1.6%, FFA 5.2%) and ceramic/veneer chipping/fracture of 1.2% (SC 0.0%, FPP 2.8%, FFA 10.5%). A 10‐year cumulative “complication‐free” survival of restorations of 88.6% (SC 91.7%, FPP 83.1%, FFA 73.8%) was reported. The complication rates differ significantly with respect to the type of restoration (p < 0.05).ConclusionsFixed restorations on locking‐taper implants seem to be a successful procedure for the rehabilitation of partially and completely edentulous arches.
Influence of Surgical and Prosthetic Techniques on Marginal Bone Loss around Titanium Implants. Part I: Immediate Loading in Fresh Extraction Sockets
Authors: Berberi Antoine N. , Tehini Georges E. , Noujeim Ziad F. , Khairallah Alexandre A. , Abousehlib Moustafa N. , Salameh Ziad A. 
Published: April 2014

AbstractPurposeDelayed placement of implant abutments has been associated with peri‐implant marginal bone loss; however, long‐term results obtained by modifying surgical and prosthetic techniques after implant placement are still lacking. This study aimed to evaluate the marginal bone loss around titanium implants placed in fresh extraction sockets using two loading protocols after a 5‐year follow‐up period.Material and MethodsA total of 36 patients received 40 titanium implants (Astra Tech) intended for single‐tooth replacement. Implants were immediately placed into fresh extraction sockets using either a one‐stage (immediate loading by placing an interim prosthesis into functional occlusion) or a two‐stage prosthetic loading protocol (insertion of abutments after 8 weeks of healing time). Marginal bone levels relative to the implant reference point were evaluated at four time intervals using intraoral radiographs: at time of implant placement, and 1, 3, and 5 years after implant placement. Measurements were obtained from mesial and distal surfaces of each implant (α = 0.05).ResultsOne‐stage immediate implant placement into fresh extraction sockets resulted in a significant reduction in marginal bone loss (p < 0.002) compared to the traditional two‐stage technique. Whereas mesial surfaces remained stable for the 5‐year observation period, significant marginal bone loss was observed on distal surfaces of implants after cementation of interim prostheses (p < 0.007) and after 12 months (p < 0.034).ConclusionsWithin the limitations of this study, immediate loading of implants placed into fresh extraction sockets reduced marginal bone loss and did not compromise the success rate of the restorations.
Removable Partial Dentures: Use of Rapid Prototyping
Authors: Lima Julia Magalhaes Costa , Anami Lilian Costa , Araujo Rodrigo Maximo , Pavanelli Carlos A. 
Published: April 2014

AbstractThe CAD/CAM technology associated with rapid prototyping (RP) is already widely used in the fabrication of all‐ceramic fixed prostheses and in the biomedical area; however, the use of this technology for the manufacture of metal frames for removable dentures is new. This work reports the results of a literature review conducted on the use of CAD/CAM and RP in the manufacture of removable partial dentures.
Comparative transcriptome analysis of Discosporangium mesarthrocarpum (Phaeophyceae), Schizocladia ischiensis (Schizocladiophyceae), and Phaeothamnion confervicola (Phaeothamniophyceae), with special reference to cell wall‐related genes
Authors: Yamagishi Takahiro , Müller Dieter G. , Kawai Hiroshi 
Published: April 2014

Within the stramenopile lineage, only brown algae (Phaeophyceae) have evolved complex multicellularity, although some other members of the lineage (e.g., Schizocladia in Schizocladiophyceae; Phaeothamnion in Phaeothamniophyceae) also develop simple multicellular thalli. The development of an adherent extracellular matrix (ECM) is considered to be one of the key steps in the evolution of multicellularity, because ECM is involved in adhesion of cells to each other and in cell–cell communication essential for developmental, reproductive, and sophisticated defense systems. Because there are no unicellular organisms within brown algae, we considered that comparison of other stramenopile taxa closely related to brown algae and having multicellular thalli could yield clues to elucidate the evolution of multicellularity in brown algae. In this study, we investigated transcriptomes involved in cell wall polysaccharide metabolism of three stramenopile species, Discosporangium mesarthrocarpum, which is suggested to be one of the most basal taxa within Phaeophyceae, S. ischiensis, and P. confervicola. We employed 454‐FLX high‐throughput pyrosequencing to generate expressed sequence tag (EST) databases for these species, and performed comparative analyses between these databases and the genome sequence of the brown alga Ectocarpus siliculosus. Results indicate that cell wall polysaccharide metabolism pathways of D. mesarthrocarpum are similar to E. siliculosus, whereas those of S. ischiensis and P. confervicola are significantly different from E. siliculosus, suggesting that the components of the cell wall in S. ischiensis and P. confervicola are likely to be different from those of E. siliculosus.
Long‐term stimulation of Toll‐like receptor 3 in primary human hepatocytes leads to sensitization for antiviral responses induced by poly I:C treatment
Authors: Broering R. , Lutterbeck M. , Trippler M. , Kleinehr K. , Poggenpohl L. , Paul A. , Gerken G. , Schlaak J. F. 
Published: April 2014

SummaryChronic hepatitis C infection is associated with increased expression of interferon‐sensitive genes (ISGs) in the liver, which is, paradoxically, correlated with the nonresponse to interferon (IFN)‐based therapies. In the present study PHHs were isolated from HCV‐infected or uninfected patients and stimulated with the TLR1‐9 ligands for 6–24 h. Expression of cytokines and ISGs was determined by ELISA and qRT‐PCR. A comparative analysis was performed for TLR3 signalling, which was also correlated with single nucleotide polymorphisms (SNPs) related to HCV pathogenesis. TLR‐activated PHHs produced pro‐inflammatory and anti‐inflammatory cytokines, whereas IFNs were exclusively induced by TLR3 stimulation. Here, IL‐29 and IL‐28A were significantly highly expressed than IFN‐α and IFN‐β. TLR3‐induced IFN response was enhanced in hepatocytes isolated from patients with HCV infection. This hyper‐responsiveness could be mimicked in naïve PHHs consistently stimulated with low dose of poly I:C, but not Guardiquimod. The higher responsiveness in PHH isolated from HCV‐infected patients could be partially explained by higher frequencies of unfavourable SNP alleles of different SNPs associated with HCV progression and treatment outcome. These data suggest that durable activation of TLR3 but not TLR7, by low doses of viral replicative intermediates, increases the sensitivity to viral invasion. These findings shed new light on the relevance of TLR3 in the pathogenesis of HCV and may provide a possible explanation for the increased ISG expression during chronic HCV infection, the so‐called IFN paradox.