Due to the current problem related to the bovine spongiform encephalopathy, bovine teeth that are specified to belong to head/neck organs, have been restricted to be used in Japan. Bovine teeth have been used as a substitute for human teeth in bond tests of various dental materials. However, the reduction of bovine teeth available may bring a situation we have to use bovine teeth regardless of their origins. Unfortunately, the influence of their origins on bond strength of adhesive systems is not clear. The purpose of this study was to investigate the effect of bovine teeth collected from 4 different places on bonding efficacy of two light-cured adhesive systems in terms of shear bond strength and topographic evaluation of fractured specimens. The results showed no significant difference in bond strength among 4 origins of bovine teeth. On the other hand, fractographical evaluations by a light microscope and SEM revealed difference in the origins. Further study is needed to clarify the characteristics of bovine teeth for the substitute of human teeth.

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The One-Up Bond F, which is one-step self etching adhesive manufuctured by Tokuyama Dental Co. Ltd., has fluoride releasing property and a novel characteristic of the color change due to the polymerization during light-irradiation. This system has been widely used in our routine clinic. Recently, the One-Up Bond F Bonding has been improved for the shorter application time. The purpose of this study was to examine the interfacial ultrastructure of the improved One-Up Bond F (One-Up Bond F Plus) under the FE-SEM by means of the Ar-ion beam etching technique. The Palfique Estelite LV was bonded to the enamel/intact dentin cavities or the dentin cavities after caries removal of the human extracted molars using this system. In a routine technique, the specimens were cut half, embedded in an epoxy resin, polished and then the resin-tooth interface was observed after Ar-ion beam etching for 35 sec under the FE-SEM. The One-Up Bond F Plus showed a tight interfacial junction to enamel/intact dentin/caries-affected dentin. The hybrid layer of the width of 0.5μm was observed in the superficial dentin layer. From the results of this study, it was suggested that this resin bonding system of which the application time was shortened might be promising for clinical use.

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This in vityo study aimed to evaluate the micro-tensile bond strengths (μ TBS) of the newly developed bonding system (One-Up Bond F Plus, OBF-plus, Tokuyama Dental Co.) and the already widely used one-step bonding system (One-Up Bond F, OBF, Tokuyama Dental Co.). Thirty extracted human molars were used in this study. After removal of enamel, middle dentin surfaces were ground flat with # 600 grit SiC paper, and then treated with OBF or OBF-plus adhesives (Tokuyama Dental Co.) using three application methods (20 seconds inactive application, 10 seconds active application and 20 seconds active application). After the adhesives were light-cured for 20 seconds, composites (Clearfil APX. Kurarav Co.) crowns were built up, followed by the storage in 37°C water for 24 hours. The specimens were then subjected to micro-tensile bond test at a crosshead speed of 1.0mm/minute. The treated dentin surfaces and the resin-dentin interfaces with OBF or OBF-plus were observed by SEM. There was no significant difference in μ TBS between OBF and OBF-plus using 20 seconds inactive application. For 10 and 20 seconds active application, μ TBS of OBF-plus was significantly higher than that of OBF. SEM observation of the treated dentin surface showed that OBF-plus with active application has an advantage of removal of the smear layer compared to OBF with active application.

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The purpose of the current study was to investigate the effect of surface preparations on bond strength to heat-pressed ceramic material (IPS Empress 2, E2) of glass-ionomer luting materials. The E2 specimens were employed as the adherend materials and E2 surface treatments for mechanical retention were; 1) etching with phosphoric acid, 2) etching with hydrofluoric acid (HF) and 3) air-abrasion with alumina. Surface treatments for chemical retention were silane treatments. Two conventional glass-ionomer materials and two resinmodified glass-ionomer materials were used as the luting agents. Shear bond strengths were determined after 24 hours.
The HF etching enhanced bond strength of all luting materials. Surface preparations for mechanical retention were effective for conventional glass-ionomer materials, nevertheless silane treatments gave negative effects. Application of the silane primer was effective for resin-modified glass-ionomer materials. Especially, conbined use of the surface preparation of HF and silane treatment was the most effective in enhancing bond strength of resinmodified glass-ionomer materials.

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The purpose of this study was to observe the resin-dentin interface after various surface treatments, and examine the relationship between the bond strength and the structure of the resin-impregnated layer. The methods of the dentinal surface treatment were divided into three groups. Group 1: etched by K-etchant, Group 2: etched by K-etchant, followed with 5% sodium hypochlorite for 60sec, Group 3: treated by the Clearfil MegaBond Primer, before application of the bonding agent, Clearfil PhotoBond (PB) or Clearfil MegaBond (MB). Firstly, the tensile bond strengths to dentin were measured, and then FESEM observation on the resin-dentin interface was performed after the argon ion beam etching or additionally treated with phosphoric acid and hypochlorite to partially remove the tooth tissues. The tensile bond strengths of each group were about 5MPa (Group 1)<7-9MPa (Group 2)<12-18MPa (Group 3), respectively. In group 1, the bonding resin monomer could not reach to the bottom of the decalcified dentin layer, while in group 3, bonding resin penetrated the decalcified dentin layer sufficiently and combined strongly with the underneath dentin layer.

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The study was aimed to investigate the effect of blue-light LED irradiation on bond strength to dentin created with 3 all-in-one adhesives (AQ Bond, AQ Bond Plus and i Bond). Extracted human premolars were used. One of the all-in-one adhesives was applied according to manufacturer's instructions on the coronal flat dentin surfaces ground with # 600 SiC papers. After irradiation with a LED apparatus (Radius, Osada Electric Co.) for 30 or 60 seconds, a resin composite was placed on it and light cured. The specimens were stored in water at 37°C for 24 hours, and then microtensile bond strength to denti nwas measured. For a control condition, irradiation with a halogen lamp was carried out followed by the manufacturers' instructions. For LED irradiation, AQ Bond did not bond to dentin. There was no difference in bond strength between 30 and 60 seconds irradiations with LED in AQ Bond Plus and i Bond. Irradiation with a halogen lamp gave higher bond strength than that with LED in i Bond. These results suggested that compatibility between catalytic systems and light sources was to be considered as well as light energy of LED in all-in-one adhesive/dentin adhesion.

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The aim of this study is to compare tensile bond strength to bovine enamel and dentin, polymerizing ratio and solubility in ethanol of AQ Bond and AQ Bond Plus by using Halogen, Xenon or LED light curing unit. The tensile bond strength of both bonding agents was measured with an Instron universal testing machine. The polymerizing ratio was measured with FT-IR based on ATR method. For the solubility in absolute ethanol of both bonding agents, residual bonding agents were observed with optical microscope after rinsing the bonding samples which were cured with each light curing unit by absolute ethanol for 5 seconds.
The following results were obtained.
1. For the tensile bond strength to enamel and dentin, AQ Bond Plus showed significantly higher strength than AQ Bond. AQ Bond Plus indicated stronger and stable bond strength by using all light curing units.
2. AQ Bond Plus showed significantly higher polymerizing ratio than AQ Bond, and the polymerizing effect of AQ Bond Plus was not influenced by using all light curing units.
3. For the solubility in ethanol of cured bonding agents, more residual cured bonding agent was observed at the sample of AQ Bond Plus.

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The purpose of this study was to evaluate the influence of surface conditions of a resin composite on polymerization of glaze coating materials by nano-indentation measurements. We prepared three surface conditions of a composite; “before light curing”, “immediately after light curing” and “removed the un-polymerized layer after light curing”. For glaze coating materials in this study BisCover (Bisco) and TOP COAT (Kuraray Medical) were used. These glaze coating materials were applied on each composite surface, and light cured under the manufacturers' directions. The nanohardness of the glaze coating materials was measured with a nano-indentation tester. From the results, the nanohardness of TOP COAT on the un-polymerized surface was significantly lower than the other surface conditions, while BisCover showed no significant differences among all surface conditions.
It was considered that the surface conditions of the resin composite influenced the polymerization of TOP COAT coated on it.

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A new magnetic attachment system was designed that a keeper was fixed directly into a resin root-coping. This study evaluated the bonding of keeper to a buildup composite for root-coping. The experimental post-keeper was made with Fe-Cr magnetic alloy and consist of a disc-keeper (H: 0.8 mm, and ∅: 3.0, 3.5, 4.0, or 4.5 mm) and a tapered-post (L: 1.5 mm, ∅: 1.5 mm). The keeper without post was used as control. The bonding surface of keeper was pretreated with one of three methods (50 μm alumina sandblasting [S], S plus application of metal-primer [S+P], or no treatment). After the keeper was placed in a buildup composite (Clearfil® Photocore) poured into acrylic tube, the composite was photo-polymerized to complete test specimen. The specimens were also fabricated that the post-keeper was bonded to a polymerized composite with the adhesive resin (Panavia® Fluoro Cement or Super-Bond C & B). Five specimens for each experimental group were subjected to 20, 000 thermocycles before tensile bond strengths were measured. The data were analyzed with ANOVA and Fisher's test (p=0.05). From the results, it was founded that the fixation which the post-keeper over the 3.5 mm diameter pretreated with S+P was bonded using Super-Bond C & B could be most effective to increase the bond durability of keeper.

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This study was aimed to evaluate the bonding efficacy of an experimental all-in-one adhesive system SSB-200 by measurement of microtensile bond strength to dentin and also by ultra-structural observation of the bonding interface under FE-SEM and TEM. Bond strength to dentin, 49.17±9.07 MPa and 65.34±13.67 MPa for two diff erent types of resin composites, was comparative to that with 2-step self-etching primer systems. FE-SEM observation revealed the tight adhesion to enamel, sound dentin and caries-affected dentin. In TEM figures, a thin hybrid layer, less than 0.5μm in thickness, was found between the bonding resin layer and dentin. Also, there was no voids formation along the bonding interface. These finding suggested that a bond mechanism in nano-level could be involved in the adhesion to dentin. From the results obtained, a good bond efficacy of SSB-200 might be promising for the clinical use.

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The Aim of this study was to assess the fatigue resistance of different types of fiber posts, and to observe their ultrastructure through a scanning electron microscopy (SEM) before and after undergoing the fatigue test. Six types of fiber posts were selected in this study. Experimental GC fiber post, Para Post Fiber White, FibreKor, DT Light-Post radiopaque, FRC Postec, and Luscent Anchors. A three-point bending machine, loading at an angle of 90° and a frequency of 3 Hz was employed for fatigue testing until 2 million cycles. SEM evaluation was performed using a 3-stepscale method to assess the fiber/resin ratio and fibers dimension. The fatigue test showed statistically significant differences among the different posts. GC fiber post and FRC Postec performed better than all the other groups, withstanding the entire load cycles. All the other posts fractured before the end of the test. SEM observations of the surface integrity of the fiber posts showed that GC fiber post, DT Light-Post radiopaque and FRC Postec obtained better scores for both longitudinal sections and the cross sections. There is a large variation of different kinds of fiber posts in response to a fatigue resistance test.

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The aim of this study was to determine the potential of fluoride-release and -uptake of various resin-based adhesives. Water sorption and solubility were also determined in relation to the potential of fluoride release. Four adhesives containing fluoride, 2-step selfetching systems 1) FB-Bond (FB) in Imperva Fluoro Bond (Shofu), and 2) BOND (PB) in CLEARFIL PROTECT BOND (Kuraray Medical), and one-step systems, 3) XENO CF II Bond (XB: Dentsply/Sankin), and 4) Reactomer Bond (RB: Shofu) were evaluated. For positive controls, a resin-modified glass-ionomer, Fuji II LC (FLC: GC) and a conventional glass-ionomer, Fuji IX (FIX: GC) were used. For negative controls, 1) Adhesive (SB) in Single Bond (3M/ESPE), 2) BOND (MB) in CLEARFIL MEGA BOND (Kuraray Medical), and 3) Bonding Agent (UB) in UniFil BOND (GC) were tested. RB and XB showed much greater fluoride-release and -uptake than those found for FB and PB. RB and XB demonstrated the nearly equivalent or more capacity of fluoride-release and -uptake than those found in glass-ionomers. Higher water sorption and solubility were found for XB, SB and RB, while FB, PB, MB and UB were relatively stable in water. Positive correlations were presented between water sorption and solubility vs. amount of fluoride release.

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