Dental Materials Journal
Online ISSN : 1881-1361
Print ISSN : 0287-4547
ISSN-L : 0287-4547
Volume 32 , Issue 6
Showing 1-21 articles out of 21 articles from the selected issue
Original Paper
  • Jan-Frederik GÜTH, Timo ZUCH, Sebastian ZWINGE, Jörg ENGELS, Michael S ...
    2013 Volume 32 Issue 6 Pages 865-871
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The aim of this study was to compare the light translucency and fluorescence 5 manually and 11 CAD/CAM polymer materials to a glass-ceramic material. Light-transmission was measured using a spectrophotometer. Overall light transmission (n=40) was calculated as the integration (tc (λ) dλ [10−5]) of all tc values for the wavelengths from 400 to 700 nm. One-Way-ANOVA, (Scheffe’s post hoc) revealed following light transmission values: Artbloc Temp (33.1%; A), Polycon ae (33.6%; A), Cercon base PMMA (38.3%; B), Luxatemp Fluorescence (40.7%; C), Protemp 4 (41.6%; C), Structur 2 SC (43.1%; D), CAD Temp (45.0%; E), Paradigm MZ 100 (45.4%; E), New Outline (45.6%,E), Ambarino High-Class (45.9%; E, F), Fixtemp C&B (46.1%; E, F, G), Lava Ultimate (47.1%; F, G), Telio-CAD (47.3%; G), glass-ceramic Vita Mark II (50.8%; H), New Outline CAD (52.1%; H, I), QUATTRO DISC Eco PMMA (53.0%; I) and Zenotec PMMA (54.5%, J). Polymers from conventional and industrial polymerization show widely varying translucent and fluorescent properties when compared with glass-ceramics of the same color.
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  • Çağdaş ÇINAR, Mesut ODABAŞ, Mügem Aslı GÜREL, İlknur BALDAĞ
    2013 Volume 32 Issue 6 Pages 872-876
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The purpose of this study was to evaluate some physical and chemical properties of MTA incorporated with antibacterial silver zeolite (SZ). 0%, 0.2% or 2% mass fraction of SZ was added to MTA powder. The amounts of calcium released from the specimen in deionized water were measured with an atomic absorption spectrophotometer. The setting times of the samples were evaluated using Gilmore-type needles. For solubility and water absorption tests, the samples were placed in a cylindrical polystyrene-sealed container. At 7 days, the samples were removed from solutions and blotted dry for solubility and water absorption test. The highest calcium release was detected in 2% SZ MTA at 24 h. The addition of 2% SZ to MTA reduced the setting time statistically (p<0.05). 2% SZ MTA was significantly more soluble than MTA and 0.2 % SZ MTA (p<0.05). Further research is needed prior to clinical use of MTA with incorporated SZ.
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  • Begüm GÜRAY EFES, Batu Can YAMAN, Burak GÜMÜŞTAŞ, Murat TİRYAKİ
    2013 Volume 32 Issue 6 Pages 877-882
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    This in vitro study aimed to investigate the effects of glass-ionomer and flowable composite liners on the fracture resistance of Class II amalgam and composite restorations. Group 1 cavities were restored with amalgam and Group 4 cavities with nanofill composite after the application of a dentin-bonding agent. For the remaining groups, light-cured-glass-ionomer liner was used in a gingival floor proximal box (Groups 2, 5) or flowable composite was used as a liner (Groups 3, 6), the remainder of the cavity was restored with amalgam (Groups 2, 3) or composite (Groups 5, 6). The restorations were loaded in compression to failure. The data was analyzed using Tukey’s multiple comparison test. The fracture resistance was significantly higher (p<0.05) in Group 3 than in all other groups, except Group 2 (p>0.05). Flowable composite, glass-ionomer liners increased the fracture resistance of open-sandwich Class II amalgam restorations.
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  • Eiji YOSHIDA, Tohru HAYAKAWA
    2013 Volume 32 Issue 6 Pages 883-887
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    Initial stage of biofilm formation is the adhesion of salivary pellicle proteins on the material surfaces. The aim of the present study was to evaluate the adsorption behaviors of saliva pellicle proteins onto a gold, silica and titanium by using the 27 MHz quartz crystal microbalance method. As pellicle proteins, lactoferrin, lysozyme, defensin and mucin were evaluated. Adsorption amount of lactoferrin to silica was significantly lower than gold and titanium. Significant differences were detected between titanium and silicafor the adsorption amounts of lysozyme. Chemical bond formation of sulfur atom of lysozyme and gold could be suggested. There were no significant differences of the adsorption amount of β-defensin among each substrate. For mucin adsorption, gold showed the highest adsorption amount. It is presumed that electrostatic repulsion caused less adsorption amounts of mucin to titanium and silica. In conclusion, the differences of the adsorption behaviors of pellicle proteins could be clearly identified.
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  • Bogna STAWARCZYK, Florian BEUER, Andreas ENDER, Malgorzata ROOS, Danie ...
    2013 Volume 32 Issue 6 Pages 888-895
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    To evaluate the influence of cementation on fracture load of anterior crowns made of CAD/CAM-resin-blocks (ART), leucite-reinforced glass-ceramics (LRG), lithium disilicate ceramics (LIT), veneered zirconia (ZRO) and veneered alloy (DEG). Each crown group (n=15/subgroup) was cemented on the metal abutment as follows: i. using glass ionomer, ii. using self-adhesive resin cement, and iii. not cemented. Crowns were tested and analyzed with 2-way and 1-way ANOVA (Scheffé test), and Weibull statistics (p<0.05). Within LRG, self-adhesive cemented subgroup showed higher fracture load compared to other groups (p<0.001). Among DEG, lower results were measured for non-cemented crowns than for cemented (p<0.001). For ART, LIT and ZRO no influence of cementation was observed. For fracture load test methodology, metal ceramic crowns should be generally cemented. Glass-ceramic crowns should be cemented using adhesive cement. Cementation and cement type did not have an influence on the fracture load results for resin, zirconia or lithium disilicate crowns.
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  • Joshua J. CHEETHAM, Joseph EA. PALAMARA, Martin J. TYAS, Michael F. BU ...
    2013 Volume 32 Issue 6 Pages 896-905
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The objective of the study was to compare 1) the mean micro-shear bond strength and 2) failure mode of cements to metals in nonenclosed and mold-enclosed specimens. Specimens were prepared in mold-enclosed and non-enclosed formats from two RMGIC’s and a self-adhesive resin-cement. 3-way ANOVA analysis and Tukey post hoc tests were used to compare mean µSBS results (α=0.05). Failure mode was analysed with Pearson’s chi-square test (α=0.05). µSBS was significantly affected by the factors substrate and method (p<0.001) but not by material (p=0.077). There was an interaction between substrate, method and material F (2,144)=3.57, p=0.031, and method and material (2,144)=5.86, p=0.004. All mold-enclosed specimens for the three cements bonded to titanium and non-precious metal exhibited higher (p<0.001) mean µSBS than the non-enclosed specimens. Within this study, mold-enclosed specimens exhibited significantly higher (p<0.001) mean µSBS and adhesive failure compared to non-enclosed specimens.
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  • Xiaozhou LIU, Robert S. JONES
    2013 Volume 32 Issue 6 Pages 906-912
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The objective of this study was to determine the efficacy of Swept Source Optical Coherence Tomography (SS-OCT) imaging in assessing a novel fissure caries model. Samples were imaged by both near infrared based SS-OCT and high resolution x-ray tomography imaging to non-destructively quantify artificial lesions. The mean relative reflectivities of the demineralized fissures were at least 6 times higher than the corresponding sound fissures (p<0.02). Importantly, this study demonstrated that SS-OCT reflectivity images can be used to predict the depth of fissure demineralization. Despite correctly evaluating the depth, this work showed that the lesion width calculated from SS-OCT reflectivity images did not accurately predict the demineralized width. The relative reflectivity could not accurately determine the mineral density of the demineralized lesions. SS-OCT detected subsurface fissure demineralization and could be used to determine if the decay process was advancing toward the enamel-dentin junction.
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  • Yakup ÜSTÜN, Soley ARSLAN, Tuğrul ASLAN
    2013 Volume 32 Issue 6 Pages 913-919
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The aim of this study was to investigate the effects of calcium hydroxide (Ca(OH)2) and propolis intracanal medicaments on bond strength of AH Plus to root dentin. After chemomechanical instrumentation using Revo-S rotary system, three groups of root canal specimens were prepared: 10 root canals were left untreated as controls (G1), 10 received Ca(OH)2 intracanal medicament (G2), and another 10 received propolis intracanal medicament (G3). Canals were obturated with AH Plus and gutta-percha. After bond strength evaluation using micro push-out test, data were analyzed using ANOVA and Tamhane’s test (p=0.05). At coronal and middle thirds, there were no significant differences in bond strength among the three groups (p>0.05). At apical third, G3 was significantly superior to G2 (p<0.05) and G1 (p<0.05), but there was no significant difference between G2 and G1 (p>0.05). Therefore, when AH Plus was used as the sealer in endodontic treatments, its combined use with propolis as an intracanal medicament seemed to result in favorable sealer-dentin interfacial bond strength.
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  • Hiroki OHNO, Kazuhiko ENDO, Futami NAGANO-TAKEBE, Yusuke IDA, Ken KAKI ...
    2013 Volume 32 Issue 6 Pages 920-927
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The residual stress caused by polymerization shrinkage and thermal contraction of a heat-curing resin containing 4-META on a metal-resin structure was measured by a scanning acoustic microscope. The tensile residual stress in the resin occurred within 70 µm of the adhesion interface with a flat plate specimen. The maximum tensile stress was about 58 MPa at the interface. On a metal plate specimen with retention holes, ring-like cracks in the resin occurred around the retention holes with the adhesive specimen and many linear cracks occurred in the resin vertical to the longitudinal direction of the metal frame with the non-adhesive specimens. There was tensile residual stress on the resin surface at the center of the retention holes of the adhesion specimen, indicating that the stress in the specimen with surface treatment for adhesion was higher than in that without surface treatment.
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  • Haifeng XIE, Chen CHEN, Wenyong DAI, Gang CHEN, Feimin ZHANG
    2013 Volume 32 Issue 6 Pages 928-938
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    This study aimed to investigate and compare the resin bond strengths of zirconia conditioned as follows: alumina sandblasting; alumina sandblasting+application of 10-MDP-containing primer; alumina sandblasting+application of Z-Prime Plus or Metal/Zirconia Primer (new zirconia primers); tribochemical silica coating+silanization; hot acid etching in three different combinations [H2SO4/(NH4)2SO4, HF/HNO3, H2SO4/HF/HNO3]+application of 10-MDP-containing primer. Shear bond strengths (SBS) after water storage for 24 h and 40 days were measured to assess resin bonding performance. Surface and chemical properties of conditioned zirconia surfaces and primers were characterized using scanning electron microscopy, energy dispersive X-ray spectrometry, Fourier transform infrared spectroscopy, and atomic force microscopy. Surface roughness ranked in descending order was: hot acid etching > tribochemical silica coating > alumina sandblasting. Combination of tribochemical silica coating and silanization showed the highest initial SBS (12.46±2.13 MPa) (P<0.01). Etching with H2SO4/(NH4)2SO4 (13.15±3.24 MPa) and HF/HNO3 (13.48±2.15 MPa) showed significantly better bond durability (P<0.01). Hot acid etching seemed to be a promising surface roughening treatment to improve resin-zirconia bonding.
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  • Ryuta MURATOMI, Kohji KAMADA, Yohsuke TAIRA, Shizuo HIGUCHI, Ikuya WAT ...
    2013 Volume 32 Issue 6 Pages 939-945
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The purpose of this study was to evaluate and compare the bond strengths between resin composite veneer and laser-sintered cobalt-chromium (Co-Cr) alloy with and without retention devices (Laser-R and Laser-N respectively). Cast Co-Cr alloy with and without retention devices (Cast-R and Cast-N respectively) were also prepared for fabrication technique comparison. Disk-shaped Co-Cr alloy specimens were air-abraded with alumina and veneered with a veneering system, Estenia C&B (ES) or Ceramage (CE). After 20,000 thermocycles, tensile testing was performed. Data were analyzed by ANOVA and multiple comparison test. When no retention devices were present, no significant differences were observed between Laser-N/ES and Cast-N/ES, or between Laser- N/CE and Cast-N/CE, but ES exhibited significantly higher bond strength than CE. With retention devices, Laser-R/ES, Cast- R/ES and Laser-R/CE showed no significant differences, and their retention strengths were significantly higher than that of Cast- R/CE. Compared to cast Co-Cr alloy, laser-sintered Co-Cr alloy with retention devices provided better retention durability for resin composite-veneered prostheses.
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  • Dongyu FANG, Ning ZHANG, Hui CHEN, Yuxing BAI
    2013 Volume 32 Issue 6 Pages 946-951
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    Mechanical properties are crucial for screening orthodontic thermoplastic materials for invisible aligners. However, most of previous studies were carried out within laboratory conditions which limit our understanding of the mechanical behaviors of aligners within oral environment. In this study, we studied the dynamic stress relaxation of thermoplastic materials by combination of Bose ElectroForce and a homemade temperature-controlled water bath. The 3-h stress relaxation curves of five orthodontic thermoplastic materials were measured within 37°C water bath as well as comparatively in ambient atmospheric environment (~20°C). The percentage residual stress at 0, 30, 60, 90, 120, 150, and 180 min was selected for statistical analyses. As expected, the experimental results showed that the residual stress within all five materials decreased with time, and that this process was significantly accelerated in the 37°C water bath (p<0.05). Compared with other materials, Erkodur and Masel exhibited slower relaxing rates in the 37°C water bath (p<0.05).
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  • Klaus-Peter KRUG, Stephanie E. OTTER, Andreas W. KNAUBER, Kurt-Juergen ...
    2013 Volume 32 Issue 6 Pages 952-958
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The purpose of this study was to evaluate the influence of the number of proximal contacts and fiber-reinforced composite (FRC) post insertion on the fracture behavior of endodontically treated premolars with class II (MOD) cavities and direct composite restorations. Forty-eight single-rooted human premolars were endodontically treated and prepared with standardized MOD (mesio-occluso-distal) cavities. One-half of the teeth additionally received FRC-posts (DT Light SL) luted with Panavia F resin cement. All of the specimens were restored with direct composite restorations, and the teeth were embedded in proximal contact with either zero, one or two adjacent tooth-replicas. Eight sound premolars served as control. After thermomechanical ageing, the samples were loaded until fracture at an angle of 30°. The sound teeth showed the highest mean fracture load. Teeth with one or two proximal contacts and FRC-posts showed only statistically insignificantly lower values. All of the other groups had significantly lower values.
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  • Takashi KAMEDA, Kazuo OHKUMA, Hirotake ODA, Natsuki SANO, Nomintsetseg ...
    2013 Volume 32 Issue 6 Pages 959-969
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    Electric toothbrushes are widely used, and their electric motors have been reported to produce low-frequency electromagnetic fields that induced electric currents in metallic objects worn by the users. In this study, we showed that electric toothbrushes generated low-frequency magnetic fields (MFs) and induced electric currents in orthodontic appliances in artificial saliva (AS), which accelerated corrosion in stainless steel (SUS) appliances, but not in titanium (Ti) appliances; the corrosion was evaluated by using an inductively coupled plasma-optical emission spectrometer and a three-dimensional laser confocal microscope. The pH of AS used for appliance immersion did not change during or after MF exposure. These results suggested that MF-induced currents from electric toothbrushes could erode SUS appliances, but not Ti appliances, because of their high corrosion potentials. Further studies are required to clarify the mechanisms of metallic corrosion by induced currents in dental fields, which may trigger metal allergies in patients.
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  • Wallapat SANTAWISUK, Widchaya KANCHANAVASITA, Chakrit SIRISINHA, Cholt ...
    2013 Volume 32 Issue 6 Pages 970-975
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The purpose of this study was to evaluate the mechanical properties of experimental silicone elastomers, Silastic® MDX 4-4210 reinforced with silica fillers, to assess its potential as a denture soft lining material. The mechanical properties measured included tensile strength, percentage elongation, tear strength, and Shore A hardness. Using one-way ANOVA and Tukey’s HSD test, the results indicated that silicone elastomers with filler loadings of 6, 8, and 10 phr had significantly greater tensile strength, percentage elongation, tear strength with a softer surface compared with commercial materials (p<0.001). In conclusion, the experimental silicone elastomers revealed acceptable mechanical properties to be used as denture soft lining materials.
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  • Keijiro HAYASHI, Keisuke HANDA, Toshiyuki KOIKE, Takashi SAITO
    2013 Volume 32 Issue 6 Pages 976-985
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    Genistein, kind of soy isoflavones, is well-known as natural ingredients and consumed as health foods and supplements. They are expected to improve renal function. They have high-affinity to estrogen receptor β expressed predominantly in bone tissue, they prevent osteoporosis specifically and safely. We examined whether genistein can be a new direct capping agent. In this study, we examined the effect of genistein for the proliferation and differentiation of rat dental pulp cells in vitro and the ability of tertiary dentin formation in vivo. As a result, rat dental pulp cells with genistein were increased activity of ALPase and showed alizarin red positive-staining. Calcification-related genes expression has been confirmed by the addition of genistein. From in vivo study, high quality of tertiary dentin formation and minor pulp reaction were observed. From these findings, it was suggested that genistein may be useful agent for direct pulp capping.
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  • Elisabeth A. KOULAOUZIDOU, Panagiota TOUPLIKIOTI, Fany ZIOUTI, Konstan ...
    2013 Volume 32 Issue 6 Pages 986-991
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    Dental bonding agents may affect the cell cycle patterns and induce cell cycle arrest by blocking its progression. This study tested the cell cycle effects through cyclin-dependent kinase (cdc2) and Rb phosphorylation. Human lung fibroblasts (MRC5) were used for the experiments. The bonding agent tested was the total-etch XP bond. Extracts of the bonding agent were prepared and serial dilutions were tested. The effects of the bonding agent on cell survival, proliferation and DNA synthesis were tested by the SRB and BrdU assays. Analysis of cell cycle distribution was performed by flow cytometry. XP bond exhibited strong inhibition of DNA synthesis and after 48 h of exposure cells were accumulated in the G2/M phase. Cells exposed to the half maximal cell growth inhibitory concentration (IC50) showed an increase in cdc2 kinase and Rb phosphorylation. The results most likely indicate mutagenic effect of the tested agent.
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  • Wakae SAKANO, Masatoshi NAKAJIMA, Taweesak PRASANSUTTIPORN, Richard M. ...
    2013 Volume 32 Issue 6 Pages 992-998
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    This study investigated the polymerization behavior within the adhesive layer of one- and two-step self-etch adhesives at the dentincomposite interface. Dentin surfaces were applied with Clearfil S3 Bond (TS), Clearfil S3 Bond Plus (TSP) and Clearfil SE Bond (SE), and then placed with a light-curing resin composite. After water storage for 24 h, the bonded teeth were sectioned and polished perpendicular to the adhesive interface, and the degree of conversion (DC) of the adhesive layer between the dentin and composite were determined using micro-Raman analysis. For all the adhesives, the DCs of the adhesive layers significantly decreased near the adhesive-composite join (p<0.05). For the maximum DC value (Pmax) and the DC value at the adhesive-composite join (Pitf), TS was significantly lower than TSP and SE (p<0.05). The polymerization of oxygen-inhibited layer at the top of the adhesive could not reach maximum DC even after polymerization of the overlying resin composite.
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  • Takako YOSHIKAWA, Makoto MORIGAMI, Alireza SADR, Junji TAGAMI
    2013 Volume 32 Issue 6 Pages 999-1004
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The aim of this study was to evaluate the effect of two slow-start curing methods on acceleration of the curing of resin composite specimens at the bottom surface. The light-cured resin composite was polymerized using one of three curing techniques: (1) 600 mW/cm2 for 60 s, (2) 270 mW/cm2 for 10 s+0-s interval+600 mW/cm2 for 50 s, and (3) 270 mW/cm2 for 10 s+5-s interval+600 mW/cm2 for 50 s. After light curing, Knoop hardness number was measured at the top and bottom surfaces of the resin specimens. The slow-start curing method with the 5-s interval caused greater acceleration of curing of the resin composite at the bottom surface of the specimens than the slow-start curing method with the 0-s interval. The light-cured resin composite, which had increased contrast ratios during polymerization, showed acceleration of curing at the bottom surface.
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  • Fuat AHMETOĞLU, Neslihan ŞİMŞEK, Ali KELEŞ, Mevlüt Sinan OCAK, Kürşat ...
    2013 Volume 32 Issue 6 Pages 1005-1010
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    The aim of this study was to evaluate the efficiencies of the self-adjusting file (SAF) system, passive ultrasonic irrigation (PUI), and conventional irrigation (CI) in removing calcium hydroxide (CH) from root canals. Fifty-one mandibular premolars were used. After root canals were instrumented and filled with a CH paste, 45 teeth were randomly assigned to three experimental groups according to CH removal technique: SAF system, PUI, or CI. The remaining 6 teeth served as positive and negative controls. All samples were evaluated by scanning electron microscopy (SEM) and scored. None of the techniques removed CH completely. However, results at coronal, middle and apical thirds showed that PUI technique was significantly more effective than SAF and CI in removing CH dressing residues from root canal walls.
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  • Seiji BAN, Yuji OKUDA, Makoto NODA, Jiro TSURUKI, Tatsushi KAWAI, Hiro ...
    2013 Volume 32 Issue 6 Pages 1011-1019
    Published: November 28, 2013
    Released: November 30, 2013
    [Advance publication] Released: November 15, 2013
    JOURNALS FREE ACCESS
    Plate-like specimens were prepared, using a diamond saw, from Cercon —a pre-sintered yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) block. These specimens were treated with 10 kinds of dental materials which acted as contaminants, and then sintered at 1,350°C or 1,450°C. After the final firing, specimens were subjected to a three-point flexural test and Vickers hardness test. Their surfaces were also characterized by scanning electron microscopy and X-ray diffractometry. Phosphorus-containing contaminants reduced the three-point flexural strength and hardness of final sintered zirconia due to the formation of YPO4 and phase transformation from tetragonal to monoclinic zirconia. Gypsum also reduced both mechanical properties due to the formation of CaZrO3 and phase transformation from tetragonal to cubic zirconia. Other contaminants showed no adverse effects on the mechanical properties of final sintered zirconia.
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