著者

Yukiko IWASAKI Hisako HIRAGUCHI Eriko IWASAKI Takayuki YONEYAMA

出版者

日本歯科理工学会

雑誌

Dental Materials Journal (ISSN:02874547)

巻号頁・発行日

vol.35, no.1, pp.45-50, 2016-01-29 (Released:2016-01-31)

参考文献数

20

被引用文献数

10

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This study investigated the effects of disinfection of agar-alginate combined impressions on the surface properties of the resulting stone casts. Two brands of cartridge-form agar impression material and one alginate impression material were used. Agar-alginate combined impressions of smooth glass plates were prepared. The impressions were immersed in 0.55% ortho-phthalaldehyde solution or 0.5% sodium hypochlorite solution for 1, 3, 5 and 10 min. A stone cast made with an impression that had not been immersed was prepared as a control. The surface roughness (Ra) of the stone casts was measured, and the cast surfaces were observed by SEM. Immersion of agar-alginate combined impressions in 0.5% sodium hypochlorite solution for up to 10 min had no serious adverse effects on the surface properties of the stone casts. In contrast, even 1 min of immersion in 0.55% ortho-phthalaldehyde solution caused deterioration of the cast surface properties.

著者

Hiroyasu KOIZUMI Haruto HIRABA Takayuki YONEYAMA Akihiro KUROIWA

出版者

The Japanese Society for Dental Materials and Devices

雑誌

Dental Materials Journal (ISSN:02874547)

巻号頁・発行日

pp.2023-113, (Released:2023-08-22)

参考文献数

63

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This review describes individual studies of removable dental prostheses, evaluated their performance and clinical applicability for the proposal to expand health insurance coverage of titanium and its alloys to removable dental prostheses. Titanium and its alloys have become clinically applicable as prosthetic materials by improving dental casting systems. They have high biosafety and good mechanical properties, are excellent substitutes for the silver-palladium-gold alloys for casting, and are highly useful for removable dental prostheses. Therefore, the introduction of health insurance coverage for removable dental prostheses made of titanium and its alloys is worthy of consideration.

著者

Haruto HIRABA Hiroyasu KOIZUMI Hiroshi NOGAWA Kosuke TAKEHANA Takayuki YONEYAMA Hideo MATSUMURA

出版者

The Japanese Society for Dental Materials and Devices

雑誌

Dental Materials Journal (ISSN:02874547)

巻号頁・発行日

pp.2022-273, (Released:2023-04-28)

参考文献数

17

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This study investigated the effect of 10-methacryloyloxydecyl dihydrogen phosphate (MDP) in methyl methacrylate (MMA) monomer on the adhesion of tri-n-butylborane (TBB)-initiated resins (MDP/MMA-TBB resins) to human enamel. Enamel surface conditions were either polished only or phosphatized surfaces. The 1.0, 1.7, and 2.0 mol% MDP/MMA-TBB resins, 4-methacryloxyethyl trimellitate anhydride (4-META)/MMA-TBB resin and MMA-TBB resin were prepared as luting materials. The shear bond strength was determined before and after thermocycles, and the results were compared using non-parametric statistical analyses (each, n=15). The MDP/MMA-TBB resins showed significantly better bond durability to enamel than other resins with or without etching. The 1.7 and 2.0 mol% MDP/MMA-TBB resins were suggested to be the optimum MDP concentrations from pre- and post-thermocycling results for the non-etched specimens. The TBB initiator resin including MDP was shown to be effective in bonding to human enamel, and this effect was enhanced in combination with phosphate treatment.

著者

Takeshi WADA Hiroyasu KOIZUMI Haruto HIRABA Takao HANAWA Hideo MATSUMURA Takayuki YONEYAMA

出版者

The Japanese Society for Dental Materials and Devices

雑誌

Dental Materials Journal (ISSN:02874547)

巻号頁・発行日

pp.2022-184, (Released:2023-03-18)

参考文献数

36

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This study evaluated the effect of luting system with acidic primers on the durability of bonds with Ti-15Mo-5Zr-3Al titanium alloy (Ti-15Mo-5Zr-3Al) and its component metals. Adherend metals were Ti-15Mo-5Zr-3Al, Ti, Mo, Zr, and Al. Four primers were evaluated as adhesion promoters: Alloy Primer (ALP), Estenia Opaque Primer (EOP), M. L. Primer (MLP), and Super Bond liquid (SBL). An acrylic resin was used as the luting material. Pre- and post-thermocycling shear bond strength was determined to evaluate the bonding durability, and the results were compared using non-parametric statistical analyses (n=11/group). The post-thermocycling bond strength in MPa (median) associated with ALP, EOP, MLP, and SBL were 18.8, 19.8, 4.1, and 0.8, respectively, for Ti-15Mo-5Zr-3Al. The results showed that two primers containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP) were effective for the durability of bonding of Ti-15Mo-5Zr-3Al to the resin. MDP enhanced the bonding durability of the resin bonded to either Ti, Zr, or Al.

著者

Haruto Hiraba Hiroyasu Koizumi Akihisa Kodaira Kosuke Takehana Takayuki Yoneyama Hideo Matsumura

出版者

Japan Prosthodontic Society

雑誌

Journal of Prosthodontic Research (ISSN:18831958)

巻号頁・発行日

pp.JPR_D_21_00308, (Released:2022-05-14)

参考文献数

32

被引用文献数

1

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Purpose: To clarify the effect of a multi-purpose primer combining several functional monomers on two prosthodontic materials (cast titanium and a gold alloy) after airborne-particle abrasion.Methods: Disk-shaped adherends were prepared from cast titanium (CP Titanium JIS2) and a gold alloy (Casting Gold M.C. Type IV). A silane-containing two-liquid primer (M&C primer (MC)) and two silane-free single-liquid primers (Alloy Primer (AP) and V-Primer (VP)) were used as surface-treatment agents. The shear bond strengths were determined before and after thermocycling to evaluate the adhesive durability, and the results were compared using a non-parametric statistical analysis. The effect of airborne-particle abrasion with alumina on the titanium surface was analyzed by X-ray photoelectron spectroscopy (XPS).Results: There was no significant difference in bond strength between the MC and AP before and after thermocycling, whereas VP showed significantly lower values. XPS revealed that the titanium acquired hydrophilic properties after the airborne-particle abrasion.Conclusions: The novelty of this study is that it shows that the presence/absence of the silane had no effect on the bonding of cast titanium with an acrylic resin. The study also showed that the multi-purpose primer can be used without any problems with both cast titanium and gold alloy, in combination with airborne-particle abrasion with alumina.

著者

Kosuke TAKEHANA Hiroyasu KOIZUMI Haruto HIRABA Akihisa KODAIRA Takayuki YONEYAMA Hideo MATSUMURA

出版者

The Japanese Society for Dental Materials and Devices

雑誌

Dental Materials Journal (ISSN:02874547)

巻号頁・発行日

pp.2021-181, (Released:2021-12-28)

参考文献数

23

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This study assessed the effect of a primer containing 10-methacryloyloxydecyl-(2-thiohydantoin-4-yl)propionate (MDTHP) on the bonding of noble metal alloys to an acrylic resin. Three noble metal alloys were selected as adherends, and V-Primer containing 6-(4-vinylbenzyl-n-propyl)amino-1,3,5-triazine-2,4-dithione was used as a comparative control. The disk specimens of each noble metal alloy were wet-ground and divided into three conditions: specimens primed with MDTHP primer or V-Primer, and specimens without priming. An acrylic resin was bonded to each specimen, and the specimens were performed the shear bond test. The MDTHP primer showed higher shear bond strength than the V-Primer for all specimens. X-ray photoelectron spectroscopic analysis showed that MDTHP was adsorbed on the Au-Pt-Pd alloy surface even after acetone cleaning. MDTHP binds not only with Cu but also with Au and Ag, promoting the bond strength of noble metal alloys. The effectiveness of MDTHP on dental noble metal alloys was suggested.

著者

Wataru MIKAMI Hiroyasu KOIZUMI Akihisa KODAIRA Haruto HIRABA Takayuki YONEYAMA Hideo MATSUMURA

出版者

The Japanese Society for Dental Materials and Devices

雑誌

Dental Materials Journal (ISSN:02874547)

巻号頁・発行日

pp.2021-137, (Released:2021-09-02)

参考文献数

26

被引用文献数

2

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This study assessed the gloss and surface roughness of computer-aided design/computer-aided manufacturing (CAD/CAM) resin composites corroded with acidulated phosphate fluoride (APF) application. One ceramic block, ten CAD/CAM resin composites for premolars, and four CAD/CAM resin composites for molars were assessed. The surface topography of the materials before and after APF application was observed using an electron microscope. The results were analyzed by Wilcoxon signed-rank test and Dunnett’s many to one test (p<0.05). Gloss after APF application was significantly lower for all CAD/CAM resin composites except Artesano. Ra after APF application was significantly higher for all CAD/CAM resin composites except Artesano, Dentcraft HR Block, and Estelite P Block, and Sa was significantly higher for all CAD/CAM resin composites. Irregular surface topography was observed after APF application and the surface features differed among the materials. Therefore, APF application may be detrimental to the surface properties of CAD/CAM resin composites.

著者

Akiko Takatsuki-Hira Masahiro Kaketani Kohei Shimizu Takahito Tamura Takeshi Nakamura Yurika Toyama Takayuki Yoneyama Osamu Takeichi

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.20-0543, (Released:2021-02-17)

参考文献数

40

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Purpose: This study aimed to examine novel techniques using prototype endodontic obturators to obturate a resin-based sealer.Methods: Powder-liquid ratios of MetaSEAL Soft were changed to obtain suitable root canal sealing, and the physical properties for various powder-liquid ratios were analyzed according to ISO-6876. Tensile bond strength was also examined. Prototype endodontic obturators with a combination of thread numbers and pitch angles were analyzed for sealing ability after MetaSEAL Soft was obturated in simulated root canals.Results: Powder-liquid ratios of 1.0:1, 1.1:1, 1.2:1, and 1.3:1 showed suitable physical properties; however, flow for 1.4:1 was below a standard value. Tensile bond strength increased gradually when the powder-liquid ratio changed from 1.0:1 to 1.3:1, and 1.3:1 and 1.4:1 showed the highest and lowest bond strengths, respectively. Sealing ability increased when pitch angles of the obturators were 5°, 8°, and 11°; 11° showed the best results. Similarly, sealing ability increased when the thread number was 12, 17, and 22 pitches; 22 showed the best results.Conclusion: These findings suggest that the prototype endodontic obturator can be useful for obturating MetaSEAL Soft, and a powder-liquid ratio of 1.3:1 MetaSEAL Soft may be the most suitable for achieving excellent sealing.

著者

Takayuki Yoneyama Takao Hanawa

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.20-0239, (Released:2020-11-12)

参考文献数

27

被引用文献数

3

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Purpose: Ni-Ti alloy has been increasingly applied to dental and medical devices, however, it contains nickel, which is known to have adverse effects on the human body. The purpose of this study was to form a nickel-free surface oxide layer on Ni-Ti alloy by electrolytic treatment for better biocompatibility.Methods: Ni-49.15Ti (mol%) alloy was used, and the electrolytic treatment was performed in the electrolytes under 50 V for 30 minutes. The electrolytes were composed of lactic acid, water, and glycerol with different compositions. Surface analysis and characterization of Ni-Ti alloy were carried out by means of X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES).Results: Results indicated that the outmost surface oxide layer was nickel-free when using an electrolyte comprising 7.1% lactic acid, 57.2% water, and 35.7% glycerol by volume. The composition of this nickel-free surface oxide layer was determined as TiO1.92(OH)1.35 ∙ 0.43H2O by XPS, similar to that of unalloyed titanium. The thickness of this nickel-free layer was estimated at 6.4 nm by AES.Conclusion: The nickel-free surface oxide layer produced on Ni-Ti alloy is considered to improve the biocompatibility of medical and dental devices having shape memory effect and/or super-elasticity.

著者

Takeshi Kase Tetsuo Ohyama Shinya Nakabayashi Hiroyasu Yasuda Takayuki Yoneyama

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.19-0427, (Released:2020-08-01)

参考文献数

25

被引用文献数

1

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In this study, analytic models were used to simulate marginal resection in the area of the second premolar to the second molar region, and the mechanical effects on the mandible of residual bone mass, a maxillofacial prosthesis, and a reconstruction plate were evaluated by three-dimensional finite element analysis. As residual bone mass decreased, maximum principal stress increased near the anterior ramus of the mandible, and maximum shear stress increased at the anterior buccal region of the resected area. In the mandible with a maxillofacial prosthesis, the maximum principal stress distribution at the anterior ramus was lower, and the distribution of maximum shear stress at the anterior buccal region of the resected area was higher. When a reconstruction plate was used, maximum principal stress and maximum shear stress were lower. Thus, lower residual bone mass was associated with increased mandible deflection and torsion. In addition, presence of a maxillofacial prosthesis decreased deflection but increased torsion, and presence of a reconstruction plate decreased deflection and greatly decreased torsion. These findings suggest that decreased residual bone mass and maxillofacial prostheses increase fracture risk; however, presence of a reconstruction plate was effective in decreasing torsional stress, thereby reducing fracture risk in the mandible.

著者

Shunsuke AKAHANE Hiroyasu KOIZUMI Akihisa KODAIRA Mitsuo NAKAMURA Takayuki YONEYAMA Hideo MATSUMURA

出版者

The Japanese Society for Dental Materials and Devices

雑誌

Dental Materials Journal (ISSN:02874547)

巻号頁・発行日

pp.2019-159, (Released:2020-05-12)

参考文献数

23

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The purpose of this study is to investigate the combined effect of two-liquid silane-phosphate primer and single-liquid sodium sulfite primer on bonding between self-polymerizing resins and feldspathic ceramics, and to promote the polymerization behavior of self-polymerizing resins at the bonding interface. The silane-phosphate primer (Super-Bond PZ Primer; PZ) and the sodium sulfite primer (Teeth Primer; TP) were used as the surface treatment agents for bonding the feldspathic ceramics and the self-polymerizing resins (MMA-TBB resin and 4-META/MMA-TBB resin). Combined PZ and TP showed high shear bond strengths. The peak of the differential scanning calorimetry curve was shown to occur early through the addition of TP. These results indicated that additional TP promoted the conversion in the initial polymerization of resin, and the firmly bond was obtained at the interface. PZ+TP treatment can be regarded as an effective treatment for a temporary splint used in teeth restoration.

著者

Yasuhiro NAMURA Yasuki UCHIDA Ryoichi SATO Noriyoshi SHIMIZU Mitsuru MOTOYOSHI Yusuke TSUTSUMI Takao HANAWA Takayuki YONEYAMA

出版者

The Japanese Society for Dental Materials and Devices

雑誌

Dental Materials Journal (ISSN:02874547)

巻号頁・発行日

pp.2019-023, (Released:2019-12-19)

参考文献数

21

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Chemical transitions after atmospheric pressure plasma irradiation were investigated by evaluating intermolecular attractions and atomic and molecular reactions. Gold, titanium and stainless-steel alloy samples were ground with #800 grit SiC waterproof paper and nitrogen gas atmospheric plasma irradiation was conducted. The surface free energies of the treated alloys were calculated and compared statistically. X-ray photoelectron spectroscopy analysis was performed.The surface free energies of all metal surfaces treated by plasma irradiation were 1.5-times higher than those of the untreated metals. The energy of the hydrogen bonding component increased, and all alloy surfaces were coated with metal oxide after only a short period of plasma irradiation. The surfaces oxidized by plasma exhibited a high active energy, mainly due to an increase in the hydrogen bonding component. Reactions with oxygen in the air were promoted on the clean surfaces with exposed reactive elements.

著者

Kentaro Okamura Hiroyasu Koizumi Akihisa Kodaira Hiroshi Nogawa Takayuki Yoneyama

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

vol.61, no.2, pp.358-363, 2019 (Released:2019-06-18)

参考文献数

21

被引用文献数

8

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The purpose of this study was to evaluate the surface properties and gloss of CAD/CAM composites after toothbrush abrasion testing. Four CAD/CAM composites for molars (Cerasmart 300, Estelite P block, Katana Avencia P block, and KZR-CAD HR3 Gammatheta), one CAD/CAM composite for premolars (Shofu Block HC Hard), and one feldspathic ceramics (Vitablocs Mark II) were assessed. Knoop hardness number, gloss, and surface roughness (Ra, Rz, and Sa) were measured before and after toothbrush abrasion testing. Knoop hardness number values were in the order Vitablocs Mark II > Katana Avencia P block > Estelite P Block > Shofu Block HC Hard > Cerasmart 300 > KZR-CAD HR3 Gammatheta. After testing, the gloss of Estelite P block and KZR-CAD HR3 Gammatheta was greatly decreased and surface roughness was greatly increased. Periodic recall and re-polishing may thus be necessary when these products are used clinically.

著者

Hiroyasu Koizumi Takaya Ishii Tomoyo Okazaki Masahiro Kaketani Hideo Matsumura Takayuki Yoneyama

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

vol.60, no.2, pp.285-292, 2018 (Released:2018-06-20)

参考文献数

38

被引用文献数

20

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The castability, mechanical properties, and fracture characteristics of Ti-15Mo-5Zr-3Al alloy were compared with those of Ti-6Al-7Nb alloy and pure titanium (CP Ti) for application of this β-type titanium alloy in cast dental prostheses. Cast specimens were prepared with a centrifugal casting machine. A tensile test was performed according to ISO standard 22674. The castability index for Ti-15Mo-5Zr-3Al was lower than those for Ti-6Al-7Nb and CP Ti. The tensile strength of Ti-15Mo-5Zr-3Al was 852 MPa, which was lower than that of Ti-6Al-7Nb and higher than that of CP Ti. The proof strength of Ti-15Mo-5Zr-3Al was 799 MPa, which was comparable to that of Ti-6Al-7Nb and higher than that of CP Ti. The elastic modulus of Ti-15Mo-5Zr-3Al was 81.0 GPa, which was lower than the values for Ti-6Al-7Nb and CP Ti. Elongation of Ti-15Mo-5Zr-3Al was 5.1%, which was comparable to that of Ti-6Al-7Nb and less than that of CP Ti. The shape of the fractured segment was narrower for Ti-15Mo-5Zr-3Al than for Ti-6Al-7Nb and CP Ti. The deformation characteristics of Ti-15Mo-5Zr-3Al may result in decreased stress relative to increased strain during plastic deformation in the stress-strain diagram. In conclusion, Ti-15Mo-5Zr-3Al alloy has a low elastic modulus and exhibits limited ductile plastic deformation in cast dental prostheses.

著者

Moeko Kato Yasuhiro Namura Takayuki Yoneyama Noriyoshi Shimizu

出版者

Nihon University School of Dentistry

雑誌

Journal of Oral Science (ISSN:13434934)

巻号頁・発行日

pp.17-0356, (Released:2018-05-31)

参考文献数

23

被引用文献数

5

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This study investigated the effect of the vertical position of the canine on changes in the frictional/orthodontic (F/O) force ratio of nickel-titanium (Ni-Ti) archwires during the initial levelling phase of orthodontic treatment. Frictional and orthodontic forces were measured by using low-friction brackets and Ni-Ti archwires with three different cross-sectional sizes and force types. To simulate canine malocclusion (first premolar extraction case), the upper right canine was displaced gingivally by 1 to 3 mm and the inter-bracket distance between the upper right lateral incisor and second premolar was set at 15 mm or 20 mm. A three-point bending test was performed to measure the orthodontic force of each Ni-Ti archwire. Frictional forces were measured with a universal testing machine and dental arch models by pulling parallel to the end of the archwire at a crosshead speed of 0.5 mm/min. F/O force ratio was calculated and analysed statistically. At a displacement of 3 mm, few archwires had F/O force ratios of less than 1.0, at which orthodontic force overcame frictional force, thus ensuring extrusion of the canine. For effective tooth movement, orthodontists should use Ni-Ti archwires with an F/O force ratio of less than 1.0.