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Hitoshi IWAI, Kou FUJITA, Hirotoshi IWAI, Takuji IKEMI, Haruhiko GOTO, ...
2013 年 32 巻 1 号 p.
1-9
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
We designed three experimental 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-based one-step (EX) adhesives consisting of MDP, urethane dimethacrylate, and triethylene glycol dimethacrylate adhesives with different water contents (98.4, 196.8, and 294.4 mg/g), and 4-methacryloyloxyethyl trimellitic anhydride (4-META) or 2-hydroxyethyl methacrylate (HEMA)-containing onestep adhesive. The effect of the amount of MDP-calcium (MDP-Ca) salt produced through demineralization of enamel and dentin on the bonding performance was examined. The efficacy of 4-META and HEMA was then discussed. When the amount of water in EX adhesive was increased, the production amount of MDP-Ca salt of enamel increased, but not the dentin. The enamel bond strength slightly increased with increasing the production amount of MDP-Ca salt, in contrast to the dentin. However, addition of 4-META in the EX adhesive (water content=98.4 mg/g) increased both bond strengths, although the production amounts of MDP-Ca salt significantly decreased. The 4-META enhances both bond strengths more effectively than the HEMA.
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Ying ZHANG, Yong WANG
2013 年 32 巻 1 号 p.
10-18
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The objective of the study was to gain more understanding on the photopolymerization mechanism and the role of individual monomers in the polymerization behavior of a PAE-based self-etch adhesive system with the presence of HAp and water. The photo-polymerization process of the model adhesive system (2MP/HEMA) was monitored by using real-time attenuated total reflectance Fourier transform infrared (ATR/FT-IR) technique. The effect of monomer ratio, HAp incorporation, and water content were investigated. The degree of conversion (DC) and the polymerization rate (PR) of the adhesives were determined to evaluate the polymerization efficacy. The results showed that the DC and PR increased consistently as the 2MP content increased from 30% to 70%, while they declined drastically as the 2MP content was further elevated to 100%. The incorporation of HAp considerably increased the DC and PR; however, the increase in water content was found to have negative influence on the photopolymerization.
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Shinji TAKEMOTO, Masayuki HATTORI, Masao YOSHINARI, Eiji KAWADA, Yutak ...
2013 年 32 巻 1 号 p.
19-24
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The objective of this study was to compare corrosion behavior in several titanium alloys with immersion in acidulated saline solutions containing hydrogen peroxide. Seven types of titanium alloy were immersed in saline solutions with varying levels of pH and hydrogen peroxide content, and resulting differences in color and release of metallic elements determined in each alloy. Some alloys were characterized using Auger electron spectroscopy. Ti-55Ni alloy showed a high level of dissolution and difference in color. With immersion in solution containing hydrogen peroxide at pH 4, the other alloys showed a marked difference in color but a low level of dissolution. The formation of a thick oxide film was observed in commercially pure titanium showing discoloration. The results suggest that discoloration in titanium alloys immersed in hydrogen peroxide-containing acidulated solutions is caused by an increase in the thickness of this oxide film, whereas discoloration of Ti-55Ni is caused by corrosion.
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Shifra LEVARTOVSKY, Guy LEVY, Tamar BROSH, Noga HAREL, Yehuda GANOR, R ...
2013 年 32 巻 1 号 p.
25-31
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The dimensional stability of a thin intra sulcular impression material reproducing the preparation finish line was evaluated. Impressions were taken of a stainless-steel master model of a simulated abutment with a ‘gingival sulcus' using Express regular, Express fast and Aquasil. The putty-wash two-step technique was applied with spacer thicknesses of 0.5, 1 and 1.5 mm. Mid mesiodistal and bucco-lingual measurements were taken directly from the sulcular impression material after 0.5, 2, 24, 48 and 72 h
via a Toolmaker's microscope. The discrepancies between the measurements of the impression material and the master model were calculated. The discrepancies changed significantly over time (
p<0.001). The use of a 0.5 mm spacer resulted in a negative deviation from the model (2-46 µm), minimally after 2 h. The use of 1 and 1.5 mm spacers showed a positive deviation from the model (21-52 µm) and both are equally recommended. Investment can be postponed until 72 h.
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Nádia da Rocha SVIZERO, Marília Santos SILVA, Roberta Caroline Bruschi ...
2013 年 32 巻 1 号 p.
32-41
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The effects of polymerization protocols on water sorption/solubility, the diffusion coefficient (
D), the flux (
J), and the hardness (KH) of two resin cements were evaluated. The materials were manipulated and divided into three groups (
n=6) according to the curing protocol: PA=photoactivation (40 s); DP=delayed photoactivation (10 min self-curing plus 40 s photoactivated); CA=chemical activation. After desiccation, the specimens were weighed, stored in water (37ºC), evaluated over 28-days, and hardness recorded. Chemical activation resulted in lower net water uptake,
D, and
J for RelyX ARC (RX). For Variolink II (VL), CA yielded equivalent
D and lower
J; however, photoactivation resulted in lower net water uptake. Hardness of VL was less affected by the water storage, irrespective of the polymerization protocol. Considering the water diffusion parameters, VL demonstrated immediate photoactivation dependence; for RX, a chemical activation. Different polymerization protocols affect the fluid kinetics and the hardness of the resin cements tested.
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Coşkun YILDIZ, Burçin Akoglu VANLIOĞLU, Buket EVREN, Altay ULUDAMAR, Y ...
2013 年 32 巻 1 号 p.
42-47
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
This study evaluated the marginal adaptation and fracture resistance of CAD/CAM-fabricated zirconia crowns luted using different luting agents. Twenty crown restorations were produced using IPS ZirCAD zirconium oxide blocks (IZC), and another 20 using Lava zirconium oxide blocks (L). Ten teeth were used as control. Luting agents used were an etch-and-rinse adhesive (Variolink II) and a self-etch adhesive (Multilink Automix). Internal and marginal adaptation was evaluated using silicone replica technique. Fracture resistance was evaluated using a compression test. Marginal discrepancy was 89.26 μm for L crowns and 88.84 μm for IZC crowns, and difference was statistically insignificant. However, L crowns showed significantly larger axial and occlusal gaps than IZC crowns (
p<0.05). Fracture resistance of IZC-Multilink was higher than the other groups, although the difference was not significant. Results showed that CAD/CAM-fabricated crowns showed acceptable
in vitro marginal discrepancies and fracture strengths.
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Soo-Kyung JUN, Dong-Ae KIM, Hyo-Jin GOO, Hae-Hyoung LEE
2013 年 32 巻 1 号 p.
48-57
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The aim of this study was to investigate the relationship between the different mechanical properties with the filler fraction of various resin composites. Mechanical properties of eighteen different resin composites were investigated in this study; flexural strength (FS), flexural modulus (FM), fracture toughness (FT), compressive strength (CS), diametral tensile strength (DTS), Barcol hardness (BH), Vickers hardness (HV), and Knoop hardness (HK). The mean values of mechanical properties and the filler fractions (V
f ) obtained from the literature and the manufacturer were analyzed using Pearson's correlation test at
p<0.01. The relationships were compared with the data retrieved from previous studies. Strong correlations between Vf and BH/HV/HK and V
f and FM were evident in the results of the present study and these results were supported by the retrieved data from previous studies. The other relationships between mechanical properties, such as that between FS and FM and between CS and HV were not significant.
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Emine SIRIN KARAARSLAN, Mehmet BULBUL, Esma YILDIZ, Asli SECILMIS, Fat ...
2013 年 32 巻 1 号 p.
58-67
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The purpose of this study was to evaluate the effect of polishing procedures on the color stability of different types of composites after aging. Forty disk-shaped specimens (Ø10×2 mm) were prepared for each composite resin type (an ormocer, a packable, a nanohybrid, and a microhybrid) for a total of 160 specimens. Each composite group was divided into four subgroups according to polishing method (
n=10): control (no finishing and polishing), polishing disk, polishing wheel, and glaze material. Color parameters (
L*,
a*, and
b*) and surface roughness were measured before and after accelerated aging. Of the polishing methods, glazed specimens showed the lowest color change (∆
E*), ∆
L*, and ∆
b* values (
p<0.05). Of the composite resins, the microhybrid composite showed the lowest ∆
E* value, whereas the ormocer showed the highest (
p<0.05). For all composite types, the surface roughness of their control groups decreased after aging (
p<0.05). In conclusion, all composite resins showed color changes after accelerated aging, with the use of glaze material resulting in the lowest color change.
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Iori GANDO, Meu ARIYOSHI, Masaomi IKEDA, Alireza SADR, Toru NIKAIDO, J ...
2013 年 32 巻 1 号 p.
68-74
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
Thin-film coating of root dentin surface by all-in-one adhesives has been shown to be an effective option to prevent root surface caries. The purpose of this study was to investigate the wear resistance against toothbrush abrasion of two all-in-one coating materials; Shield Force (SF) and Hybrid Coat (HC). Bovine dentin surfaces were covered with one of the coating materials; SF or HC. After storage in water for 24 h, the testing surface was subjected to the toothbrush abrasion test up to 50,000 cycles either in water or toothpaste slurry. The remaining thickness of the coating material was measured using SEM. Toothpaste slurry significantly increased rate of tooth brush abrasion of the coating materials. While SF and HC wore at a similar pace under toothbrush abrasion, SF had a thicker coat and could protect dentin longer, up to 50,000 cycles.
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Rena TAKAHASHI, Jian JIN, Toru NIKAIDO, Junji TAGAMI, Reinhard HICKEL, ...
2013 年 32 巻 1 号 p.
75-82
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The present study was designed to evaluate the surface roughness and the gloss of current composites before and after toothbrush abrasion. We assessed forty dimensionally standardized composite specimens (
n=8/group) from five composites: two nanohybrids (
i. e., IPS Empress Direct Enamel and IPS Empress Direct Dentin), two microhybrids (
i. e., Clearfil AP-X and Filtek Z250) and one organically modified ceramics (Admira). All of the specimens were polished with 4000-grid silicon carbide papers. Surface roughness was measured with a profilometer and gloss was measured with a glossmeter before and after powered toothbrush abrasion with a 1:1 slurry (dentifrice/tap water) at 12,000 strokes in a toothbrush simulator. There was a significant increase in the surface roughness and a reduction in gloss after toothbrush abrasion in all of the composites except Clearfil AP-X (
p<0.05). Simple regression analysis showed that there was not an association between the surface roughness and the gloss (
R2=0.191,
p<0.001).
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Tomotaro NIHEI, Naohiro OMOTO, Katsura OHASHI, Yoshiyuki KONDO, Norio ...
2013 年 32 巻 1 号 p.
83-87
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
Three novel aqueous fluoride surfactants (F4, F6, and F8) and a positive control (10F2S-3I) were applied to bovine enamel and the surface free energy was calculated by measuring the surface contact angles of three liquids: distilled water, α-bromonaphthalene and diiodomethane. The specimens were stored in water for 90 days, and then immersed in acetic acid/sodium acetate. The modified specimens recorded higher contact angles and lower surface free energy immediately after treatment than the control (
p<0.05). Less calcium dissolved from the modified enamel surfaces than the control, with the F8-modified specimen registering significantly lower values than those of the F4, F6 and 10F2S-3I groups (
p<0.05). These results suggest that the novel aqueous phosphate-type fluoride surfactant F8 is the most effective anti-cariogenic surface modifier.
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Shizuka YAMADA, Hideaki NAGAOKA, Masahiko TERAJIMA, Nobuaki TSUDA, Yos ...
2013 年 32 巻 1 号 p.
88-95
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
Collagen is one of the most widely used biomaterials for tissue engineering and regenerative medicine. Fish collagen peptides (FCP) have been used as a dietary supplement, but their effects on the cellular function are still poorly understood. The objective of this study was to investigate the effects of FCP on collagen synthesis, quality and mineralization using an osteoblastic MC3T3-E1 cell culture system. Cells treated with FCP significantly upregulated the gene expression of several collagen modifying enzymes and more collagen was deposited in the cultures. Collagen in the treated group showed a greater extent of lysine hydroxylation, higher levels of hydroxylysine-aldehyde derived cross-links and accelerated cross-link maturation compared with the untreated group. Furthermore, the treated group showed accelerated matrix mineralization. These results indicate that FCP exerts a positive effect on osteoblastic cells in terms of collagen synthesis, quality and mineralization, thereby suggesting the potential utility of FCP for bone tissue engineering.
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Deepti SHRESTHA, Wan-Cui WU, Qing-Yin HE, Xi WEI, Jun-Qi LING
2013 年 32 巻 1 号 p.
96-100
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The aim of this study was to investigate the effect of sodium ascorbate (Sa) on degree of conversion (DC) and bond strength (BS) of RealSeal SE to sodium hypochlorite (NaOCl) treated root dentin. Two hundreds simulated canals were prepared and irrigated with Distilled water(DW), 1.3% NaOCl (1.3% N), 5.2% NaOCl (5.2% N), MTAD, 17% EDTA (EDTA), 10% Sa, 1.3% NaOCl/MTAD (N-M), 1.3% NaOCl/Sa/MTAD(N-Sa-M), 5.2% NaOCl/EDTA(N-E), and 5.2% NaOCl/Sa/EDTA (N-Sa-E) respectively. They were subsequently bulk filled with RealSeal SE and analyzed with micro-Raman spectroscopy and universal testing machine for DC and BS respectively. One-way ANOVA and post hoc Tukey's test showed DC of 1.3% N, 5.2% N, N-M and N-E were significantly lower (
p<0.01) than other six groups. BS of DW, Sa, N-M were significantly lower than 1.3% N, 5.2% N, MTAD, EDTA, N-Sa-M and N-E (
p<0.01), and group N-Sa-E achieved the highest BS among all groups (
p<0.01). NaOCl negatively affected DC and BS of RealSeal SE, which could be reversed with 10% Sa.
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Masahiro EGAWA, Tadashi MIURA, Tetsuo KATO, Atsushi SAITO, Masao YOSHI ...
2013 年 32 巻 1 号 p.
101-106
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
Tetragonal zirconia polycrystals (TZP) has drawn attention as a potential alternative to titanium (Ti) in dental implant treatment, as it minimizes both allergic reactions and esthetic problems. It is also important for dental implants to maintain plaque-free surfaces to prevent peri-implantitis. The purpose of this study was to investigate
in vitro adherence of periodontopathic bacteria to TZP comparing with Ti.Periodontopathic bacteria were cultured on polished discs of two kinds of TZP, and Ti as a control. After incubation, the numbers of adherent bacteria were estimated. No significant differences among specimens were observed in the initial attachment, although a decrease was observed in initial attachment to saliva-coated specimens. In the bacterial colonization, no significant differences were recognized among specimens. The adherence of the periodontopathic bacteria on TZP was similar to that on Ti. These results suggest that a strategy is required for inhibition of the bacterial adherence to TZP.
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Ferhan EGILMEZ, Gulfem ERGUN, Isil CEKIC-NAGAS, Pekka K. VALLITTU, Lip ...
2013 年 32 巻 1 号 p.
107-114
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The purpose was to determine the short and long term effects of polishing systems and post-heat-light curing on the color stability of nano-composites. The disc shaped samples (ø=10 mm, h=3 mm) were prepared. Forty subgroups (
n=5) were designed according to two different curing conditions and five different polishing methods. Color change measurements were performed on the day of specimen preparation (base) and repeated after 1 and 7 months of water storage. MANOVA and Tukey's post hoc tests were applied (
p<0.05). While the color difference values of resin composites were ranked as EXP2>EXP1>CME≥XTE after 1 month (
p<0.05), after 7 months the ranking was EXP2≥EXP1>XTE>CME (
p<0.05). Type and compositions of nano-composites may be important on the long-term color stability of the restoration. Additional post-heat-light curing of nano-composites may produce higher color change than the hand-light curing protocol. Consequently, the polishing procedures should be applied to obtain more resistant composite surface to discoloration.
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Yuya YONEYAMA, Tomonori MATSUNO, Yoshiya HASHIMOTO, Tazuko SATOH
2013 年 32 巻 1 号 p.
115-121
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
Surface modification of titanium has been extensively investigated in implant science and technology in an effort to improve its osteoconductivity. The rate of protein adsorption on titanium surfaces is known to vary depending on the chemistry, structure, morphology, and titanium-specific biological aging of the surface. It is thus desirable to modify smooth titanium surfaces of miniimplants used as orthodontic anchors immediately prior to use. In this study, we have developed a simple surface modification of titanium alloy that improves its biofunctional activity. The surface of a Ti-6Al-4V disk was modified by applying 3% H
2O
2 hydrothermal treatment using an autoclave. A nanostructured porous network TiO
2 was observed on the treated surface. Treated surfaces exhibited higher hydrophilicity, protein adsorption, and cell proliferation than untreated surfaces. 3% H
2O
2 hydrothermal treatment is thought to provide biofunctional activity for aged titanium surface.
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Hiroshi ITO, Hodaka SASAKI, Kensuke SAITO, Shinya HONMA, Yasutomo YAJI ...
2013 年 32 巻 1 号 p.
122-129
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The objective of this study was to clarify the effect of surface topography on osteoblast-like cell behavior on yttria stabilized tetragonal zirconia polycrystals (TZP). Mirror-polished; blasted with 50- or 150-µm alumina (SB50 and SB150); and SB150 acid-etched with hydrofluoric acid (SB150E) were prepared on TZP. Initial attachment, proliferation and differentiation of MC3T3-E1 were evaluated. The scanning electron microscopy and Sdr (developed interfacial area ratio) values indicated that both micro- and nano-topographies produced on the SB150E surfaces. Although no clear differences were observed in initial cell attachment among specimens, the proliferation rate and expression of ALP activity on the SB150E specimens was significantly higher than that on the other specimens. These results indicate that the creation of micro- and nano-topographies on TZP by surface treatment offers a promising method of enhancing the proliferation and differentiation of MC3T3-E1 cells.
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Hitoshi SAKAUE, Kei KOMATSU, Toshihiko YOSHIOKA, Hitomi ISHIMURA, Arat ...
2013 年 32 巻 1 号 p.
130-137
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The aim of this study was to investigate coronal leakage after obturation with mineral trioxide aggregate (MTA), resin-based sealer, and silicon-based sealer for open apical foramina and to evaluate pathway of leakage. Twenty-eight maxillary premolars were used, and instrumented to ISO size #80. Teeth were randomly divided into four groups as follows: Group A filled with MTA, Group B with gutta-percha and resin-based sealer, Group C with polymer-based material and resin-based sealer, and Group D with gutta-percha and silicon-based sealer. All samples were evaluated for coronal leakage with methylene blue solution and spectrophotometry. After leakage testing, samples were cut, and sections were observed. Dye leakage of Group A was significantly lowest among all groups at 15 days and 30 days. Defects which induced coronal leakage in resin-based sealer were observed at 7 mm from the apex. Coronal leakage after obturation with MTA for open apical foramina was significantly lower than resin-based sealer and silicon-based sealer.
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Gerardo José JOVES, Go INOUE, Syozi NAKASHIMA, Alireza SADR, Toru NIKA ...
2013 年 32 巻 1 号 p.
138-143
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
This study aimed to investigate an artificial caries-affected dentin (ACAD) model for
in vitro bonding studies in comparison to natural caries-affected dentin (NCAD) of human teeth. ACAD was created over 7 days in a demineralizing solution. Mineral density (MD) at different depth levels (0-150 µm) was compared between NCAD and ACAD by transverse microradiography. Micro-tensile bond strengths (µTBS) of two two-step self-etch adhesives to sound dentin, NCAD and ACAD were evaluated. Caries-affected dentin type was not a significant factor when comparing MD at different lesion levels (
p>0.05). Under SEM, the dentinal tubules appeared occluded with crystal logs 1-2 µm in thickness in the NCAD; whereas they remained open in the ACAD. The µTBS to caries-affected dentin was lower than sound dentin, but was not affected by the type of caries (
p>0.05). In spite of their different morphologies, the ACAD model showed similar MD and µTBS compared to NCAD.
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Takuya KIHARA, Yuko SHIGETA, Rio HIRABAYASHI, Tomoko IKAWA, Eriko ANDO ...
2013 年 32 巻 1 号 p.
144-149
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The purpose of this present study was to investigate the influence of material filler and RGB values' fluctuation on creating a calibration curve, which indicates the relationship between material thickness and transmitted light brightness using the transillumination method. Creating the calibration curves were carried out through the following three methods; 1) the conventional method creates the calibration curve with a formula of thickness, 2) the maximum value method, with samples of a specified thickness, and 3) the actual value method, with a microscope. Furthermore, the reliability of each curve was verified
via scanned artificial tooth data. In addition, the characteristics of light decrement were investigated. From our results, it was suggested that the filler diameter must be considered when the calibration curve is created using the bite impression material with a filler. In addition, it was suggested that the RGB values' fluctuation did not influence the calibration curve.
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Maho SHIOZAWA, Hidekazu TAKAHASHI, Werner J. FINGER, Naohiko IWASAKI
2013 年 32 巻 1 号 p.
150-155
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
Aim of this study was to investigate effects of space thickness and consistency of wash materials on sulcus depth reproduction with silicone impressions, low (L), medium (M), and very high consistency (VH), using two-step putty-wash technique. Impressions were taken from truncated cones with 50-, 100-, or 200-μm-wide sulci, using the combinations L+VH or M+VH and different space thickness for wash materials: 2 mm (ST2), 1 mm (ST1), and approximately 25 μm (ST0.025). Sulcus depth reproduction tended to increase with increasing sulcus width. Sulcus reproduction of ST0.025 was deeper than those of the other groups. At 100- and 200-μm sulcus widths, sulcus reproductions of ST1 and ST2 with L+HV were deeper than with M+HV. Regardless of consistency, the thin spacer produced deep reproduction. Adequate 0.5 mm sulcus reproductions were obtained with 100 and 200 μm wide sulci and 1- and 2-mm spacer widths, combined with low consistency impression material.
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Masahiro IIJIMA, Shuichi ITO, Susumu NAKAGAKI, Takeshi MUGURUMA, Naohi ...
2013 年 32 巻 1 号 p.
156-164
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
This study investigated fluoride release, acid resistance and shear bond strength (SBS) of new 4-META/MMA-TBB-based fluoridecontaining resin adhesive (Super-Bond/F3). Super-Bond, Transbond Plus and Fuji Ortho LC were selected for comparison. Fluoride release into distilled water during 6-month period was measured using disk-shaped specimens. Brackets were bonded to human premolars with each material and then the specimens for the nanoindentation test were subjected to alternating immersion (demineralizing and remineralizing solutions); the hardness and elastic modulus of the enamel around bracket were determined. Rest of the specimens was subjected to examine the SBS. Super-Bond/F3 and Fuji Ortho LC showed significantly greater fluoride release compared with the other materials. The reductions in hardness and the elastic modulus for Super-Bond/F3 and Fuji Ortho LC were lower than those for the other materilas. Super-Bond and Super-Bond/F3 showed significantly greater SBS than Fuji Ortho FC. In conclusion, Super-Bond/F3 showed high fluoride-release, cariostatic potential and equivalent SBS.
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Christie Ying Kei LUNG, Edwin KUKK, Jukka Pekka MATINLINNA
2013 年 32 巻 1 号 p.
165-172
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The effect of silica-coating by sol-gel process on the bond strength of resin composite to zirconia was evaluated and compared against the sandblasting method. Four groups of zirconia samples were silica-coated by sol-gel process under varied reagent ratios of ethanol, water, ammonia and tetraethyl orthosilicate and for different deposition times. One control group of zirconia samples were treated with sandblasting. Within each of these five groups, one subgroup of samples was kept in dry storage while another subgroup was aged by thermocycling for 6,000 times. Besides shear bond testing, the surface topography and surface elemental composition of silica-coated zirconia samples were also examined using scanning electron microscopy and X-ray photoelectron spectroscopy. Comparison of silica coating methods revealed significant differences in bond strength among the Dry groups (
p<0.001) and Thermocycled groups (
p<0.001). Comparison of sol-gel deposition times also revealed significant differences in bond strength among the Dry groups (
p<0.01) and Thermocycled groups (
p<0.001). Highest bond strengths were obtained after 141-h deposition: Dry (7.97±3.72 MPa); Thermocycled (2.33±0.79 MPa). It was concluded that silica-coating of zirconia by sol-gel process resulted in weaker resin bonding than by sandblasting.
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Hiroyuki MINAMI, Sadaaki MURAHARA, Koichi MURAGUCHI, Kenji SAKOGUCHI, ...
2013 年 32 巻 1 号 p.
173-180
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
This study evaluated the effects of combined use of metal primers and modified monomers on the bonding of MMA-TBBO resins to pure palladium (Pd). Bonding surface was polished with 600-grit silicon carbide paper and primed with one of these four metal primers: V-Primer, M. L. Primer, Metaltite, or Alloy Primer. Four monomers, including three modified ones, were added to MMATBBO resin. One was a methyl methacrylate monomer containing no adhesion promoting monomers, while the other two modified monomers contained the functional monomer of either V-Primer or Alloy Primer. Bonded specimens were prepared by incremental build-up of MMA-TBBO resin on primed Pd surfaces. Shear bond strengths were measured after thermal cycling. Bonding to Pd was significantly improved when modified monomer containing the functional monomer of Alloy Primer was used in combination with M. L. Primer or Metaltite applied on the bonding surface.
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Yusuke HASHIMOTO, Yoshiya HASHIMOTO, Aki NISHIURA, Naoyuki MATSUMOTO
2013 年 32 巻 1 号 p.
181-188
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
Orthodontists use a self-etching adhesive system when attaching brackets to enamel. The purpose of this study was to evaluate the erosion effects of common clinically used adhesive systems on human enamel surfaces by atomic force microscopy (AFM). Four commercially available adhesive systems (
i. e., Kurasper F, Beauty Ortho Bond, Orthophia LC, and Transbond XT) were applied to ground enamel surfaces of extracted human teeth. Enamel surface roughness (ESR), absolute depth profile (ADP), and surface hardness were evaluated by AFM. The ESR and ADP were significantly higher after the pretreatment with the phosphoric acid-etching adhesive system than after the pretreatments with the three self-etching adhesive systems. The surface nanohardness decreased after the pretreatment with the phosphoric acid-etching adhesive system but increased after the pretreatments with the self-etching adhesive systems. These results suggest that the use of a self-etching primer for enamel conditioning might prevent decalcification caused by phosphoric acid etching.
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Satoshi OMORI, Wataru KOMADA, Keiichi YOSHIDA, Hiroyuki MIURA
2013 年 32 巻 1 号 p.
189-194
発行日: 2013/01/31
公開日: 2013/02/01
ジャーナル
フリー
The aim of the present study was to evaluate the fracture load and fracture mode of thin Ceria-stabilized tetragonal zirconia polycrystals/Al
2O
3 nanocomposites (Ce-TZP/A) and Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) crown frameworks. Artificial maxillary second premolars were prepared for metal-ceramic crown and all-ceramic crown restorations and Co-Cr tooth analogs were duplicated. 10 standard (0.5 mm overall thickness) zirconia-ceramic crown frameworks (Y-TZPs) for all-ceramic crown preparation and 10 modified (a 0.3-mm-thick framework increased in thickness by adding a 1.0-mm-thick palatal margin with a height of 2.0 mm) zirconia-ceramic crown frameworks (Y-TZPm, Ce-TZP/Am) for metal-ceramic crown preparation were fabricated. The frameworks were cemented to the Co-Cr tooth analog and loaded vertically until fracture. The fracture load of Y-TZPs (180.0 N) and Ce-TZP/Am (183.7 N) were significantly higher than that of Y-TZPm (133.7 N). There was a significant difference in fracture mode between Y-TZPm and Ce-TZP/Am. Within the limitation of this study, Ce-TZP/Am provide sufficient strength for clinical application.
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