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Mojtaba MAHMOUDI, Alireza SAIDI, Saied Abdolreza GANDJALIKHAN NASSAB, ...
2012 Volume 31 Issue 2 Pages
171-179
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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This article has been retracted by the Editorial Board of Dental Materials Journal due to violation of our publishing policies and procedures as of December 1,2013.
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Rebecca FREEMAN, Srinivas VARANASI, Ian A. MEYERS, Anne L. SYMONS
2012 Volume 31 Issue 2 Pages
180-188
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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This study examined the effect of air abrasion and thermocycling on the adaptation and shear bond strength, of composite resin bonded to dentin using etch-and-rinse and self-etch resin adhesives. Confocal microscopy showed both adhesives closely adapted to dentin and a significantly (
p<0.001) greater number of resin tags were observed for the etch-and-rinse adhesive. Air abrasion significantly increased resin tag length (
p<0.05) for the etch-and-rinse adhesive and significantly increased the number (
p<0.001), length (
p<0.001) and thickness (
p<0.01) of tags for the self-etch adhesive. However, air abrasion resulted in defect formation within the hybrid layer and thermocycling caused separation of the hybrid layer from adjacent dentin containing resin tags. A significant (
p<0.05) reduction in shear bond strength was observed for the etch-and-rinse adhesive following thermocycling. Both adhesive systems adapted well to dentin
in vitro and shear bond strengths were similar. The area of tag penetration into dentin was significantly (
p<0.0001) enhanced following air abrasion.
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Daiichiro YOKOYAMA, Akikazu SHINYA, Harunori GOMI, Pekka K. VALLITTU, ...
2012 Volume 31 Issue 2 Pages
189-196
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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Using finite element analysis (FEA), this study investigated the effects of the mechanical properties of adhesive resin cements on stress distributions in fiber-reinforced resin composite (FRC) adhesive fixed partial dentures (AFPDs). Two adhesive resin cements were compared: Super-Bond C&B and Panavia Fluoro Cement. The AFPD consisted of a pontic to replace a maxillary right lateral incisor and retainers on a maxillary central incisor and canine. FRC framework was made of isotropic, continuous, unidirectional E-glass fibers. Maximum principal stresses were calculated using finite element method (FEM). Test results revealed that differences in the mechanical properties of adhesive resin cements led to different stress distributions at the cement interfaces between AFPD and abutment teeth. Clinical implication of these findings suggested that the safety and longevity of an AFPD depended on choosing an adhesive resin cement with the appropriate mechanical properties.
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Akiko SAKAI, Alireza VALANEZAHAD, Masao OZAKI, Kunio ISHIKAWA, Shigeki ...
2012 Volume 31 Issue 2 Pages
197-205
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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Sr-containing carbonate apatite (SrCAp) specimens of varied Sr contents, ranging from 0 to 13.3 mol%, were prepared through a phosphate treatment of set gypsum-and-carbonate mixture at 100°C for 7 days. Effects of Sr content in SrCAp on microstructure, osteoblast-like cell (MC3T3-E1) attachment and proliferation, and alkaline phosphatase (ALP) activity were evaluated. Sr
2+ ion substituted Ca
2+ ion in the apatite lattice. Carbonate content was about 9–13.6 wt%, increasing in content level as Sr content increased. Sr addition benefited cell attachment but had no significant influence on cell proliferation, although the latter was inhibited at the highest Sr content. ALP activity reached a peak in specimen containing 3.4 mol% of Sr. The present study revealed that SrCAp is a promising candidate for use as a bone substitute material with good resorbabilty and osteoconductivity.
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Ozgul BAYGIN, Fatih Mehmet KORKMAZ, Ipek ARSLAN
2012 Volume 31 Issue 2 Pages
206-214
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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The aim of this
in vitro study was to evaluate the effects of different types of adhesive systems on the microleakage of compomer restorations in Class V cavities prepared by erbium, chromium: yttrium scandium gallium garnet (Er,Cr:YSGG) laser. There were five test groups according to the type of adhesive applied to the cavities: Adper Single Bond 2 (Group 1), Scotchbond Multi-Purpose Plus (Group 2), Xeno III (Group 3), Clearfil Protect Bond (Group 4), Prime&Bond NT (Group 5). Dye penetration was evaluated under a stereomicroscope, and data were statistically analyzed by Kruskal-Wallis and Wilcoxon Signed Ranks tests. Gingival margins showed significantly higher microleakage than occlusal margins in all the test groups (
p<0.05). Groups 1 and 2 showed significantly less microleakage than Group 5 (
p<0.05), and there were no statistically significant differences among Groups 3, 4, and 5 (
p>0.05). None of the dentin bonding agents eliminated microleakage completely, and higher microleakage scores were observed along the gingival margin than the occlusal margin.
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Yujin AOYAGI, Kozo UMEMOTO, Shigeaki KURATA
2012 Volume 31 Issue 2 Pages
215-218
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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This study evaluated the chemical properties such as water sorption, water solubility and solvent resistance of a new resin material consisting of 1,3-bis(3-methacryloxypropyl)-1,1,3,3-tetramethyldisiloxane (BMPMS) and methyl methacrylate (MMA). Water sorption was evaluated by immersing the specimens in water at 37±1°C for 1 week, water solubility was evaluated by keeping the specimens in a desiccator under dry conditions at 37±1°C until the weight became constant, and solvent resistance was evaluated by immersing the specimens in acetone for 1 week and measuring the dissolved weight of acetone volatilized from those liquids. The water sorption and solvent resistance of the new resin were improved with increasing amount of BMPMS, whereas the water solubility remained the same value and did not depend on the amount of BMPMS.
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Shigeaki KURATA, Kumiko MORISHITA, Toshio KAWASE, Kozo UMEMOTO
2012 Volume 31 Issue 2 Pages
219-225
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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The purpose of this study was to evaluate the cytotoxicity of acrylic and methacrylic acid (AA and MA), propanoic acid and isobutylic acid (PRA and IBA) which were the corresponding saturated carboxylic acids, 2-hydroxylethyl methacrylate and acrylate (HEMA and HEA), and hydroquinone (HQ). The growth of the fibroblast when exposed to AA decreased with increase of the acid, and was less than when exposed to MA. The growth when exposed to their corresponding saturated acids, PRA and IBA, showed a similar tendency to AA and MA. The growth of fibroblasts exposed to 5 mmol/L HEMA after 4 days and 3 mmol/L HEMA after 6 days was significantly different compared with that without HEMA. The growth in 1, 3, and 5 mmol/L of HEA after 2 days was markedly decreased compared with that without HEA, and the cells were probably lifeless. The growth when exposed to HQ was extremely lower than their acids.
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Soley ARSLAN, Hüseyin ERTAS, Yahya Orçun ZORBA
2012 Volume 31 Issue 2 Pages
226-231
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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This study investigated the effect of Ankaferd Blood Stopper (ABS) contamination on bond strength of total- and self-etching systems. Seventy mandibular third molars sectioned in a mesio-distal direction were mounted in acrylic resin, and flat dentin surfaces were exposed. The specimens were randomly assigned to seven groups (
n=20), according to the surface treatment: Group I, ABS contamination+37% phosphoric acid+Solobond M; Group II, ABS contamination+Clearfil SE Bond; Group III, ABS contamination+All Bond SE; Group VI, 37% phosphoric acid+ABS contamination+Solobond M; Group V, Solobond M; Group VI, Clearfil SE Bond; and Group VII, All Bond SE. Next, a resin composite (Grandio) was built up using a plastic apparatus and polymerized. The specimens were tested in shear mode at a crosshead speed of 1 mm/min. There were significant differences in bond strengths between the control and ABS-contaminated samples. These findings suggest that ABS contamination reduced bond strength of total- and self-etching adhesives.
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Go INOUE, Toru NIKAIDO, Alireza SADR, Junji TAGAMI
2012 Volume 31 Issue 2 Pages
232-238
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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This study investigated the influence of the composition of self-etching primer adhesive systems on the morphology of acid-base resistant zones (ABRZs). One-step self-etching primer systems (Clearfil Tri-S Bond, G-Bond, and One-Up Bond F Plus) and two-step self-etching primer systems (Clearfil SE Bond, Clearfil Protect Bond, UniFil Bond, and Mac Bond II) were used in this study. Each adhesive was applied on prepared dentin disk surfaces, and a resin composite was placed between two dentin disks. All resin-bonded specimens were subjected to acid-base challenge. Observation under a scanning electron microscope (SEM) revealed the creation of an ABRZ adjacent to the hybrid layer for all the self-etch primer adhesive systems, even when non-fluoride releasing adhesives were used. The presence of fluoride in two-step self-etching adhesive significantly increased the thickness of ABRZ created. Results suggested that an ABRZ was created with the use of self-etching primer adhesive systems, but its morphology differed between one-and two-step self-etching primer adhesive systems and was influenced by fluoride release activity.
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Ping SUN, Jingxiao WANG, Yuanna ZHENG, Yi FAN, Zhiyuan GU
2012 Volume 31 Issue 2 Pages
239-248
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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This study aimed to compare the effects of bone morphogenetic protein BMP2/7 heterodimer and BMP homodimers on bone regeneration in bone defects model. Identical peri-implant bone defects model were created using proper controls on the frontal skull in 18 minipigs. Collagen sponges with low-dose (30 ng/mL) BMP2/7 heterodimer, BMP2 or BMP7 homodimer were filled in the defects. New bone formation and the expression of type I collagen (Col1), alkaline phosphatase (ALP) and osteocalcin (OCN) were evaluated after 2, 3, and 6 weeks of implantation. BMP2/7 resulted in significantly higher new bone areas percentage in the defect region than BMP2 and BMP7 (
p<0.05). Immunohistochemical staining of Col1, ALP and OCN was stronger in BMP2/7 group than BMP2, BMP7 and control group (
p<0.05). These results demonstrate that BMP2/7 heterodimer is a stronger inducer of osteoblastogenesis and could be applied at low dose to reduce the cost and side effects of BMP homodimers.
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Youssef S. AL JABBARI, Spiros ZINELIS, George ELIADES
2012 Volume 31 Issue 2 Pages
249-255
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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This study determined the effect of grit size and application pressure on alumina fragment retention after sandblasting in representative dental alloys. Plastic rectangular patterns (25×3×0.6 mm,
n=240) were divided equally into four groups and cast with Au-Pt, Ni-Cr, Co-Cr alloys and grade-II cp-Ti. The specimens from each alloy were then divided into 12 subgroups. Each subgroup was then sandblasted with one of the 12 possible combinations of grit size (50, 100 and 250 microns) and propulsion pressure (0.15, 0.30, 0.45 and 0.60 MPa), and their surfaces imaged and analyzed using SEM/EDS analysis. The Al composition was statistically analyzed by two-way ANOVA with Tukey’s post-test. Materials tested showed a substantial amount of retained alumina fragments, the extent of which was dependent on the grit size and propulsion pressure applied for tested alloys except cp-Ti. Importantly, sandblasting conditions different from those proposed by the manufacturers achieved lower levels of retained alumina fragments.
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Jorge PERDIGÃO, Ana M. PINTO, Regina C.C. MONTEIRO, Francisco M ...
2012 Volume 31 Issue 2 Pages
256-265
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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The aim was to investigate the effect of simulated low-temperature degradation (s-LTD) and hydrothermal fatigue on the degradation of three ZrO
2-based dental materials. Lava, IPS, and NanoZr discs were randomly assigned to (1) Control-Storage in distilled water at 37°C; (2) Aging at 134°C for 5 h (s-LTD); (3) Thermocycling in saliva for 30,000 cycles (TF). XRD revealed that ZrO
2 m phase was identified in all groups but TF increased the
m phase only for Lava. Under the FESEM, Lava showed no alterations under s-LTD, but displayed corrosion areas up to 60 μm wide after TF. We conclude that TF accelerated the degradation of Lava through an increase in the
m phase and grain pull-out from the material surface.
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Gabriel FURTOS, Bogdan BALDEA, Laura SILAGHI-DUMITRESCU, Marioara MOLD ...
2012 Volume 31 Issue 2 Pages
266-272
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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Digital radiography was used to measure the radiopacity of 18 resin cements to determine the influence of inorganic filler content on radiopacity. Four disk specimens (
n=4) of each light-curing cement were digitally radiographed alongside an aluminum step wedge using an intraoral sensor (XIOS Plus, Sirona, Germany), and their mean gray value measured. Percentage of filler by weight was determined using an analytical combustion furnace. Data were statistically analyzed using one-way ANOVA and Tukey’s test (α=0.05). All materials were more radiopaque than dentin and 12 materials were more radiopaque than enamel. Filler percentage ranged between 17.36 to 53.56 vol% and radiopacity between 1.02 to 3.40 mm Al. There were no statistically significant differences in inorganic filler percentage and radiopacity among the different shades of the same material (
p>0.05), but the highest radiopacity was measured for the material which contained a higher percentage of filler.
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Ekamon MAHAPOKA, Pratanporn ARIRACHAKARAN, Anyarat WATTHANAPHANIT, Rat ...
2012 Volume 31 Issue 2 Pages
273-279
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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A resin-based sealant containing chitosan whiskers was developed for use as a pit and fissure sealer. Chitosan whiskers were synthesized and then characterized using fourier transform infrared spectrometry and transmission electron microscopy. The whiskers were next incorporated into dimethacrylate monomer at various ratios by weight and subsequently analyzed for their antimicrobial and physical properties. The dimethacrylate-based sealant containing chitosan whiskers had a greater antimicrobial activity than control sealant and they were comparable with antimicrobial commercial resin sealants. The inclusion of the whiskers did not reduce the curing depth or degree of double bond conversion and the reduction in hardness was minimal. In conclusion, a resin-based sealant containing chitosan whiskers can be considered an effective antimicrobial pit and fissure sealant.
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Hisako HIRAGUCHI, Masahiro KAKETANI, Hideharu HIROSE, Takayuki YONEYAM ...
2012 Volume 31 Issue 2 Pages
280-286
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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This study investigated the effect of the immersion of alginate impressions in 0.5% sodium hypochlorite solution for 15 min on the dimensional changes of stone models designed to simulate a sectional form of a residual ridge. Five brands of alginate impression materials, which underwent various dimensional changes in water, were used. A stone model made with an impression that had not been immersed was prepared as a control. The immersion of two brands of alginate impressions that underwent small dimensional changes in water did not lead to serious deformation of the stone models, and the differences in the dimensional changes between the stone models produced with disinfected impressions and those of the control were less than 15 μm. In contrast, the immersions of three brands of alginate impressions that underwent comparatively large dimensional changes in water caused deformation of the stone models.
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Kouki TADA, Toru SATO, Masao YOSHINARI
2012 Volume 31 Issue 2 Pages
287-296
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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In all-ceramic restorations involving a zirconia framework, surface treatment of the zirconia surface is required to enhance bonding strength with the veneering ceramics and thus prevent chipping. The purpose of the present study was to investigate the influence of surface roughness and heat treatment of the zirconia and use of liner porcelain on bond strength between veneering ceramics and a zirconia framework. Debonding/crack-initiation strength (
τb) was determined according to ISO 9693. No significant difference was observed among conditions, except with use of a liner under heat treatment, which yielded a
τb of 26.0±2.9–28.9±1.7 MPa. Electron probe microanalysis revealed that components of the veneering ceramics remained on the zirconia surface after debonding, suggesting that fractures occur in the veneering ceramics and that improving the strength of the veneering ceramics themselves might increase bond strength.
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Ryo KANBARA, Yoshinori NAKAMURA, Kent T. OCHIAI, Tatsushi KAWAI, Yoshi ...
2012 Volume 31 Issue 2 Pages
297-308
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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The purpose of this study was to develop and report upon a methodology for a non-linear capacity 3D modeling finite element analysis evaluating the loading behavior of different partial denture designs. A 3D finite element model using human CT data was constructed. An original material constant conversion program was implemented in the data simulation of non-linear tissue behavior. The finite element method material properties of residual ridge mucosa were found to have seven material constants and six conversion points of stress values. Periodontal tissues were found to have three constants, and two conversion points. Three magnetic attachment partial denture designs with different bracing elements were evaluated. Technical procedures for finite element model simulation of nonlinear tissue behavior properties evaluating the oral behavior of prosthetic device designs are reported for prosthodontic testing. The use of horizontal cross-arch bracing positively impacts upon the comparative stability of the partial denture designs tested.
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Fukunaga OTSUKA, Yu KATAOKA, Takashi MIYAZAKI
2012 Volume 31 Issue 2 Pages
309-315
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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The purpose of this study is to investigate the surface characteristics and biocompatibility of titanium (Ti) surfaces modified by wire electrical discharge machining (EDM). EDM surface characteristics were evaluated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), thin-film X-ray diffractometry (XRD) and contact angle measurements. MC3T3-E1 cell morphology, attachment and proliferation, as well as analysis of osteoblastic gene expressions, on machined surfaces and EDM surfaces were also evaluated. EDM surfaces exhibited high super hydrophilicity, due to high surface energy. XPS and XRD revealed that a passive oxide layer with certain developing thickness onto. EDM surfaces promoted cell attachment, but restrained proliferation. Counted cell numbers increased significantly on the machined surfaces as compared to the EDM surfaces. Real-time PCR analyses showed significantly higher relative mRNA expression levels of osteoblastic genes (ALP, osteocalcin, Runx2, Osterix) in cells cultured on the EDM surfaces as compared to cells cultured on the machined surfaces.
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Yasuko TAKAYAMA, Rie NOMOTO, Hiroyuki NAKAJIMA, Chikahiro OHKUBO
2012 Volume 31 Issue 2 Pages
316-326
Published: 2012
Released on J-STAGE: April 03, 2012
Advance online publication: March 23, 2012
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The purpose of this study was to evaluate the effects of the rate of argon gas flow on joint strength in the laser-welding of cast metal plates and to measure the porosity. Two cast plates (Ti and Co-Cr alloy) of the same metal were abutted and welded together. The rates of argon gas flow were 0, 5 and 10 L/min for the Co-Cr alloy, and 5 and 10 L/min for the Ti. There was a significant difference in the ratio of porosity according to the rate of argon gas flow in the welded area. Argon shielding had no significant effect on the tensile strength of Co-Cr alloy. The 5 L/min specimens showed greater tensile strength than the 10 L/min specimens for Ti. Laser welding of the Co-Cr alloy was influenced very little by argon shielding. When the rate of argon gas flow was high, joint strength decreased for Ti.
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