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Yukyo TAKADA, Masayuki ITO, Kohei KIMURA, Osamu OKUNO
2005 年 24 巻 2 号 p.
153-162
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The electrochemical properties and released ions of binary Au-1.6mass%Ti alloy were evaluated in 0.9% NaCl and 1% lactic acid solutions and compared with those of Au-Ag-Pd alloy and Type 4 gold alloy. Rest potential and anodic polarization curve of Au-1.6mass%Ti alloy were almost the same as those of pure gold regardless of thermal condition (softening, hardening, or as cast). Among the alloys in comparison, the anodic polarization curve of Au-1.6mass%Ti alloy showed that it had the least current density and best stability when subject to electrochemical oxidation. Though Au-1.6mass%Ti alloy did release a small amount of Ti ions in 1% lactic acid solution, the amount of released Ti ions was not more than 1/5 of the amount released by pure titanium under the same condition. In the same vein, the total amount of ions released from Au-1.6mass%Ti alloy was much lower than that of the precious alloys in both solutions.
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Eisei HAYASHI, Masafumi KIKUCHI, Osamu OKUNO, Kohei KIMURA
2005 年 24 巻 2 号 p.
163-171
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
In this study, the grindability of cast magnetic alloys (Fe-Pt-Nb magnetic alloy and magnetic stainless steel) was evaluated and compared with that of conventional dental casting alloys (Ag-Pd-Au alloy, Type 4 gold alloy, and cobalt-chromium alloy). Grindability was evaluated in terms of grinding rate (
i. e., volume of metal removed per minute) and grinding ratio (
i. e., volume ratio of metal removed compared to wheel material lost). Solution treated Fe-Pt-Nb magnetic alloy had a significantly higher grinding rate than the aged one at a grinding speed of 750-1500m·min
-1. At 500m·min
-1, there were no significant differences in grinding rate between solution treated and aged Fe-Pt-Nb magnetic alloys. At a lower speed of 500m·min
-1 or 750m·min
-1, it was found that the grinding rates of aged Fe-Pt-Nb magnetic alloy and stainless steel were higher than those of conventional casting alloys.
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Yoshiharu MUKAI, Kiyoshi TOMIYAMA, Toru SHIIYA, Kazuko KAMIJO, Fukue F ...
2005 年 24 巻 2 号 p.
172-177
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
This study evaluated the capability of a novel fluoride-releasing, all-in-one adhesive system on forming inhibition layer (radio-opaque layer) as compared with other adhesive systems. Dentin surface was treated with Imperva bond (TB), FL-BOND (FB), Reactmer bond (RE), or FL-BOND S-1 (FS) (which is a novel system). Untreated specimens were categorized as nonbonding group (NB). After storing for 10 days in de-ionized water, the specimens were cut into halves perpendicularly to the pulp chamber and immersed in a buffered demineralizing solution for four days. Longitudinal sections were cut and microradiographed. The width of inhibition layers adjacent to the adhesive surface—at a depth of 50μm under the demineralization surface—was analyzed. Microradiography revealed distinct inhibition layers adjacent to the experimental surfaces of FB, RE, and FS. No inhibition layers were observed in NB and TB. In particular, the width of the inhibition layer of FS (12.5μcm) was significantly greater than those of FB and RE. These results indicated that a newly developed all-in-one adhesive system, FS, may have a superior ability of forming inhibition layers adjacent to cavity walls, and that it may also protect dentin against further demineralization in case of secondary marginal caries.
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Akhtar UZZAMAN, Yasushi SHIMADA, Yuichi SEKI, Junji TAGAMI
2005 年 24 巻 2 号 p.
178-186
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
This study evaluated the pulpal response of hybrid composite resin inlay luted with a resin-modified glass ionomer cement, and compared it with a glass ionomer cement and an amalgam. Cervical cavities were prepared in monkey teeth. A resin-modified glass ionomer luting cement (Ionotite F, Tokuyama Dental Corp.) was applied to the teeth in one of the experimental groups, and then hybrid composite resin inlays (Estenia, Kuraray Medical Inc.) were bonded to the cavities. The teeth were extracted after 3, 30, and 90 days and stained with Hematoxylin and Eosin staining or Brown and Brenn gram stain for bacterial observation. No serious inflammatory reaction of the pulp, such as necrosis or abscess formation, was observed in any of the experimental groups. No bacterial penetration along the cavity walls was detected in the resin-modified glass ionomer luting cement group. Hence, the resin-modified glass ionomer luting cement showed an acceptable biological compatibility with monkey pulp.
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Kazuyo YAMAMOTO, Koichiro SUZUKI, Sayaka SUWA, Hidehiko MIYAJI, Yasuak ...
2005 年 24 巻 2 号 p.
187-194
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The dentin bonding durability of a total-etch adhesive system (Prime & Bond
® NT) was investigated by tensile bond test using conventional and dumbbell-shaped specimens. Two bonding techniques were compared. After etching and rinsing, dentin surface was either blotted by cotton ball (wet-bonding) or air-dried (dry-bonding) before bonding agent was applied. The bond strength of wet-bonding specimens was significantly higher than that of dry-bonding for both conventional and dumbbell-shaped specimens after one day. The bond strength of wet-bonded conventional specimens did not decrease after two years of water immersion, but cohesive failure in demineralized dentin was observed after two years. Wet-bonded dumbbell-shaped specimens showed cohesive failure within demineralized dentin after only one day. The bond strength of drybonded conventional specimens decreased significantly after one year, and cohesive failure in demineralized dentin was confirmed after three months. As for dry-bonded dumbbell-shaped specimens, they showed cohesive failure in demineralized dentin after one month. The results of the present study showed that the bonding durability of dry-bonded Prime & Bond
® NT restorations was lower than that of wet-bonded restorations. Further, by using tensile bond test, cohesive failure in demineralized dentin was detected earlier in dumbbell-shaped specimens than in conventional specimens.
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Tomoko ABO, Shigeru UNO, Junji TAGAMI
2005 年 24 巻 2 号 p.
195-201
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
Possibility to shorten the total irradiation time in slow-curing with an intensity-changeable light source, Curetron 7 (CT-7), was investigated for four hybrid-type resin composites. Irradiation condition with CT-7 was assigned as 10 or 20 seconds at low light intensity (230mW/cm
2) and followed by 20 or 10 seconds at high intensity (600mW/cm
2) respectively (i. e., a total of 30 seconds). For a reference, irradiation was carried out for 30 seconds using a halogen lamp (900mW/cm
2). After irradiation, mechanical properties of the cured composites—in terms of microhardness and flexural strength—were evaluated. Also, cavity adaptation was examined in standardized, cylindrical dentin cavities treated with an adhesive system. Compared to the reference irradiation, slow-curing with CT-7 produced acceptable mechanical properties and better adaptation. These results suggested that total exposure time of slow-curing with CT-7 could be shortened to 30 seconds.
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Seiichiro FUJISAWA, Eitoku MURAOKA, Yoshihiro NAKAZATO, Norihisa OKADA
2005 年 24 巻 2 号 p.
202-206
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The purpose of this study was to evaluate the histopathological effects of eugenol (EUG) and iso-eugenol (IsoEUG)—with or without visible light (VL) irradiation—on oral mucous membranes. Oral mucous membranes of mice were applied with three agents, EUG, IsoEUG, and aceton (as the control) in the absence or presence of VL irradiation. VL irradiation resulted in more tissue damage for EUG- or IsoEUG-treated mucosa compared to corresponding compounds without VL irradiation, and that damage under IsoEUG treatment was greater than that under EUG treatment. Necrosis, but not apoptosis, was preferentially expressed in EUG- or IsoEUG-treated mucous membranes in the presence of VL irradiation.
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Tetsuya YUASA, Youji MIYAMOTO, Masayuki KON, Kunio ISHIKAWA, Masaaki T ...
2005 年 24 巻 2 号 p.
207-212
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
Effects of functionally gradient calcium phosphate consisting of hydroxyapatite (HAP) and α-tricalcium phosphate (α-TCP) on proliferation and differentiation of osteoblasts were evaluated using MC3T3-E1 cells. There were no significant differences in the proliferation of MC3T3-E1 cells among HAP-α-TCP functionally gradient calcium phosphate, pure HAP, and cell culture plastic wells. mRNA expressions of type I collagen, alkaline phosphate, and osteocalcine were evaluated as indexes of initial, mid-stage, and late-stage osteoblastic differentiation. Basically, HAP-α-TCP functionally gradient calcium phosphate and pure HAP enhanced the expressions of the three markers when compared with that of cell culture plastic wells. For type I collagen and alkaline phosphate expressions, HAP-α-TCP functionally gradient calcium phosphate showed the same expression level as pure HAP. For osteocalcine expression, HAP-α-TCP functionally gradient calcium phosphate showed a higher level than pure HAP. We concluded, therefore, HAP-α-TCP functionally gradient calcium phosphate has good potential to be a bone filler material with high osteoconductivity.
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Tohru HAYAKAWA, Kazuyo KIKUTAKE-SUGIYAMA, Kimiya NEMOTO
2005 年 24 巻 2 号 p.
213-218
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The self-etching primer adhesives examined in the present study were aqueous mixtures of 30wt% 2-methacryloyloxyethyl phenyl hydrogen phosphate, 35wt% 2-hydroxyethyl methacrylate, and photoinitiator. For the photoinitiator, camphorquinone (CQ) or 2-hydroxyl-3- (3, 4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy) -N, N, N-trimethyl-1-propanaminium chloride (QTX) was used—where QTX is a unique water-soluble photoinitiator. The self-etching primer adhesive was applied directly to polished bovine dentin or enamel. Tensile bond strength of flowable composite resin to bovine teeth was measured after one-day immersion in water at 37°C. The addition of QTX tended to increase tensile bond strength to dentin, whereby addition of 3wt% of QTX produced the highest mean bond strength of approximately 10MPa. CQ, on the other hand, did not show any efficacy in improving bond strength. For enamel bonding, there were no significant differences in bond strength between CQ and QTX. In conclusion, QTX was effective in improving the bond strength of composite resin to dentin in an all-in-one bonding system.
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Tsuyoshi KITAGAWA, Yasuhiro TANIMOTO, Kimiya NEMOTO, Masahiro AIDA
2005 年 24 巻 2 号 p.
219-224
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
Using finite element method (FEM), this study sought to investigate how the thickness and Young's modulus of cortical bone influenced stress distribution in bone surrounding a dental implant. The finite element implant-bone model consisted of a titanium abutment, a titanium fixture, a gold alloy retaining screw, cancellous bone, and cortical bone. The results showed that von Mises equivalent stress was at its maximum in the cortical bone surrounding dental implant. Upon investigation, it was found that maximum von Mises equivalent stress in bone decreased as cortical bone thickness increased. On the other hand, maximum von Mises equivalent stress in bone increased as Young's modulus of cortical bone increased. In conclusion, it was confirmed that von Mises equivalent stress was sensitive to the thickness and Young's modulus of cortical bone.
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Shuhai HU, Takayuki OSADA, Takashi SHIMIZU, Kenji WARITA, Tadaharu KAW ...
2005 年 24 巻 2 号 p.
225-231
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The aim of this study was to evaluate the resistance to fracture of endodontically treated teeth with flared canals restored with different post and core restorations under static and cyclic fatigue loadings. Sixty human maxillary central incisors were used. Two main groups (non-ferrule and 1-mm ferrule) were divided into three types of restoration: custom cast post-and-core (MPC), resin composite post-and-core (RCP), and resin composite core in combination with prefabricated carbon fiber post (FRC). Half of each group was subjected to a static loading test, and the other to a cyclic fatigue test. FRC exhibited a significantly higher number of load cycles than the other groups, and MPC showed the highest failure load among the tested groups. However, all FRC and MPC specimens demonstrated unfavorable root fractures. The results of this study suggested that RCP prepared with 1-mm ferrule was the most desirable restoration for structurally compromised roots, as relatively strong resistance to cyclic fatigue and fracture was revealed—given that all RCP specimens demon-strated favorable root fracture.
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Rie YOKOMICHI, Yohsuke TAIRA, Kohyoh SOENO, Mitsuru ATSUTA
2005 年 24 巻 2 号 p.
232-237
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The purpose of this study was to evaluate the effect of multi-step conditioning (PA-AD conditioning) with phosphoric acid and sodium hypochlorite on the bond strength of five luting materials to enamel and dentin. Three commercial self-etching/priming systems (Panavia, Linkmax, and Multibond) and two experimental systems (ED/Super-Bond and EDFe/Super-Bond) were used. The surfaces of bovine enamel or dentin were bonded to a stainless steel rod. Tensile bond strength was determined after 24-hour immersion in water. PA-AD conditioning significantly improved the bond strength between enamel and three of the systems (Panavia, ED/Super-Bond, and EDFe/Super-Bond), but did not have any effect on Linkmax and Multibond. Likewise, PA-AD conditioning did not significantly improve the bond strength of Panavia, Linkmax, Multibond, and ED/Super-Bond to dentin. Highest bond strength to dentin (19.7MPa) was obtained when self-etching primer containing ferric chloride (EDFe/Super-Bond) was used, but additional PA-AD conditioning significantly weakened the bonding (12.6MPa).
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Masaomi IKEDA, Toru NIKAIDO, Richard M. FOXTON, Junji TAGAMI
2005 年 24 巻 2 号 p.
238-243
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
A hybrid ceramic, Estenia
®, is a highly-filled composite for indrect use. The purpose of this study was to measure the shear bond strength between Estenia
® and six incremental materials: Estenia
®, Cesead II
®, Epricord
®, Gradia
®, Prossimo
®, and Solidex
®. Five specimens were prepared for each group, and all specimens were subjected to shear bond strength testing at a cross-head speed of 1mm/min. Data were analyzed using two-way ANOVA and Dunnett's T3 test at 95% confidence level. The results indicated that the shear bond strength of Estenia
® to Estenia
® was significantly lower than that of any other combinations. Apart from storage condition that was found to influence shear bond strength statistically, thermal cycling of the specimens also tended to decrease the bond strength between Estenia
® and the incremental materials. It was concluded that regularly-filled composites are suitable to be used as an incremental material facing Estenia
® in combination technique.
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Taichi KAZUNO, Tadao FUKUSHIMA, Tohru HAYAKAWA, Yusuke INOUE, Rieko OG ...
2005 年 24 巻 2 号 p.
244-250
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The purpose of this study was to investigate the antibacterial activity of MMA/TBB resin containing newly developed amphiphilic lipids. The amphiphilic lipids, C10-L-Ala/pts and C12-L-Ala/pts, synthesized from the reaction of n-alkyl alcohol and L-alanine were dissolved in MMA at concentrations of 0.5, 1.0, 1.5, and 2.0mol%. Resin mixtures of PMMA powder and each MMA liquid containing lipid and TBB were prepared for all tests. Both lipids gave antibacterial effect to MMA/TBB resin. The addition of C12-L-Ala/pts to MMA resulted in a significantly higher antibacterial activity than the addition of C10-L-Ala/pts. In terms of bond strength, the bond strength of MMA/TBB resin to bovine dentin was significantly decreased by the addition of amphiphilic lipids. But for enamel, the bond strength of MMA/TBB resin with amphiphilic lipids was clinically acceptable for orthodontic brackets. In conclusion, amphiphilic lipids will be useful as a component of adhesive resin to give the latter an antibacterial effect.
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Tohru HAYAKAWA, Kazuyo KIKUTAKE-SUGIYAMA, Tadao FUKUSHIMA, Kimiya NEMO ...
2005 年 24 巻 2 号 p.
251-256
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The self-etching primer adhesives examined in the present study were aqueous mixtures of 5wt% MDP, 35wt% HEMA, 3wt% 2-hydroxyl-3-(3, 4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N, N, N-trimethyl-1-propanaminium chloride (QTX), 0.5wt% ethyl-
p-(N, N-dimethylamino) benzoate (EDM), and 30wt% water-soluble dimethacrylate (
i. e., 2, 2-bis (4-methacryloxy polyethoxypheny) propane (BPE), Glycerol dimethacrylate (GMR), or Glycerol methacrylate acrylate (GAM)). Self-etching primer adhesive was directly applied to polished bovine teeth. Tensile bond strength of composite resin to bovine teeth was measured after one-day immersion in water at 37°C. Differences in water-soluble dimethacrylate monomer did not produce any significant differences in tensile bond strength to dentin or enamel. The use of N-phenyliminodiacetic acid (PIDAA) instead of EDM showed significantly higher bond strength to dentin and enamel. In conclusion, GMR and GAM were useful as water-soluble dimethacrylates while the combination of PIDAA and QTX was effective in improving the bond strength of composite resin to teeth in an all-in-one bonding system.
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Takako IDE, Naomi TANOUE, Hiroaki YANAGIDA, Mitsuru ATSUTA, Hideo MATS ...
2005 年 24 巻 2 号 p.
257-260
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The purpose of the present study was to evaluate the bond strength and durability of four bonding systems joined to a prefabricated porcelain material (Vita Celay Blanks). Two sizes of porcelain block were bonded with one of the following systems: (1) Clapearl Bonding Agent and Clapearl DC; (2) Imperva Porcelain Primer and Imperva Dual; (3) Monobond S and Variolink II; or (4) Tokuso Ceramics Primer and Bistite II. Shear bond strength was measured after 24-hour immersion in water and after subsequent thermocycling. The average pre- and post-thermocycling bond strengths in MPa (n=8) were: 52.5 and 42.5 for bonding system (1), 47.7 and 32.8 for (2), 55.0 and 48.8 for (3), and 51.5 and 25.6 for (4). Although prethermocycling results were not statistically different from each other, Group (3) exhibited the greatest strength after thermocycling.
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Juthatip AKSORNMUANG, Masatoshi NAKAJIMA, Richard M. FOXTON, Junji TAG ...
2005 年 24 巻 2 号 p.
261-267
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The purpose of this study was to evaluate the regional bond strength of a dual-cure resin core material to root canal dentin using four self-etching primer/adhesive systems. Post spaces were prepared in extracted premolars, and their root canal dentin was treated with one of the following self-etching primer/adhesive systems: ED Primer II and Clearfil Photobond, photo-cure/dual-cure systems of Clearfil Liner Bond 2V, or Clearfil SE Bond. Post spaces were filled with the dual-cure resin core material, and microtensile bond strength (μTBS) at the coronal and apical regions was measured after 24-hour storage. There were no regional differences in μTBS of the photo-cure and dual-cure systems of Clearfil Liner Bond 2V, while μTBS at the coronal region of Photobond and SE Bond groups were higher than those at the apical region. At the apical region, photo-cured Clearfil Liner Bond 2V exhibited significantly higher bond strength than those of the other systems.
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Masayuki ITO, Masafumi KIKUCHI, Osamu OKUNO, Kohei KIMURA
2005 年 24 巻 2 号 p.
268-274
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The aim of this investigation was to evaluate the metal-ceramic bonding of Au-1.6wt%Ti alloy. Therefore, the coefficient of thermal expansion, modulus of elasticity, ceramic bonding strength, and hardness of Au-1.6wt%Ti alloy were measured. The metal-ceramic interface was observed by EPMA to investigate its bonding mechanism. The Au-1.6wt%Ti alloy showed a coefficient of thermal expansion close to that of conventional precious metal alloys for metal-ceramics. Bonding strength was 25MPa or higher for all specimens—whether ceramic-fired directly after casting, or following oxidation treatment or age hardening. Specimens subjected to oxidation treatment showed slightly lower post-firing hardness than those age-hardened. EPMA observation showed an accumulation of Ti and O contents on the alloy side at the metal-ceramic interface.
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Takashi NAKAMURA, Tatsuo OHYAMA, Tomonori WAKI, Soichiro KINUTA, Kazum ...
2005 年 24 巻 2 号 p.
275-279
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
Two-dimensional finite element models were created for a three-unit posterior fixed partial denture. An experimental resin-impregnated glass fiber was used as the fiber-reinforced composite (FRC) for the framework. The FRC was evaluated using varying combinations of position and thickness, alongside with two types of veneering composite. A load of 50N simulating bite force was applied at the pontic in a vertical direction. Tensile stress was examined using a finite element analysis program.
Model without FRC showed tensile stress concentrations within the veneering composite on the cervical side of the pontic—from the connector area to the bottom of the pontic. Model with FRC at the top of the pontic had almost the same stress distribution as the model without FRC. Models with 0.4-0.8mm thick FRC positioned at the bottom of the pontic showed maximum tensile stresses reduced by 4-19% within the veneering composite.
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Denis Yudi NAGASE, Shinji TAKEMOTO, Masayuki HATTORI, Masao YOSHINARI, ...
2005 年 24 巻 2 号 p.
280-285
発行日: 2005年
公開日: 2010/02/24
ジャーナル
フリー
The purpose of this study was to compare the retention force of FRC posts which were built up using direct and direct-indirect fabrication techniques with two fiber-reinforced core build-up systems (FibreKor and i-TFC). Posts were cemented in endodontically treated bovine single roots with resin cement using either direct or direct-indirect technique. Following which, the retention force of post-and-cores and fracture sites were examined. It was found that both the retention force and fracture site depended on the fabrication technique and resin cements. Post-and-cores built up with direct-indirect technique had greater retention force than those fabricated using direct technique. Fracture modes most frequently observed were adhesive failure at Resin/Dentin interface, a mixture of adhesive failures at Post/Resin and Resin/Dentin interfaces as well as cohesive failure of resin cements. Based on the results of this study, we concluded that when it comes to post-and-core build-up for endodontically treated tooth, the direct-indirect technique is more effective than the direct technique on the retention force of FRC posts.
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