Biomedical subjects

Hidehiko Sano

Publications and source records attributed to Hidehiko Sano.

At least 19 recordsLinked to original sources

PubMed2007

Hybrid layer seals the cementum/4-META/MMA-TBB resin interface.

Although 4-META/MMA-TBB resin has adhesive properties to dentin, and has been clinically used for the bonding treatment of vertically fractured roots and apicoectomy, there has not been any investigation on the adhesion of 4-META/MMA-TBB resin to cementum. The purpose of this in vitro study was to evaluate the bonding and the sealing ability of 4-META/MMA-TBB resin to cementum. Bovine root cementum and dentin surfaces were treated with a citric acid and ferric chloride solution, and the 4-META/MMA-TBB resin was applied on the treated surfaces before testing. The microtensile bond strength and the leakage levels obtained for the cementum were almost equal to those for the dentin. In SEM and TEM observations, a hybrid layer approximately 2-3 microm in thickness was observed at the interface between the resin and the cementum. It is concluded that 4-META/MMA-TBB resin adhered to cementum via a hybrid layer on cementum, as previously reported for dentin.

Acid Etching, Dental↗

PubMed2006

NaOCl degradation of a HEMA-free all-in-one adhesive bonded to enamel and dentin following two air-blowing techniques.

OBJECTIVE: Phase-separation within HEMA-free all-in-one dental adhesives may result in the entrapment of droplets within the adhesive resin. Strongly air-blowing prior to polymerization, can remove most of these droplets. The objective of this study was to evaluate the effect these droplets may have on the resistance of the adhesive-tooth interface to NaOCl degradation. METHODS: The micro-tensile bond strength (microTBS) to enamel and dentin was determined when a HEMA-free all-in-one adhesive was applied either following a mild or strong air-blowing technique. The bonds were also exposed to an aqueous sodium hypochlorite (NaOCl) solution for 1h, following a recently introduced methodology to mimic in vivo bond degradation. RESULTS: This study revealed that strong air-blowing of the adhesive only resulted in a significantly higher micro-tensile bond strength (microTBS) to dentin, but not to enamel. Likewise, NaOCl only reduced the microTBS to dentin for both the mild and strong air-blowing technique, but again not the microTBS to enamel. Failure analysis by SEM clearly revealed that strong air-blowing is less effective in droplet removal when the adhesive was applied in small and narrow class-I cavities, as compared to when it was applied to flat surfaces. CONCLUSIONS: NaOCl did preferentially dissolve the hybrid layer at dentin, and more for the mild than for the strong air-blowing technique. A strong air-blowing procedure resulted in a more NaOCl-resistant hybrid layer, so that it can be concluded that a HEMA-free one-step adhesive definitely benefits from a strong air-blowing technique.

Air↗

PubMed2006

CD14 directly binds to triacylated lipopeptides and facilitates recognition of the lipopeptides by the receptor complex of Toll-like receptors 2 and 1 without binding to the complex.

It has demonstrated that the recognition of triacylated lipopeptides by Toll-like receptor (TLR) 2 requires TLR1 as a coreceptor. In the NF-kappaB reporter assay system in which human embryonic kidney 293 cells were transfected with TLR2 and TLR1 together with an NF-kappaB luciferase reporter gene, S-(2,3-bispalmitoyloxypropyl)-N-palmitoyl-Cys-Lys-Lys-Lys-Lys (Pam(3)CSK(4)) and Pam(3)CSSNA were recognized by TLR2/TLR1, but the recognition level was unexpectedly very low. However, cotransfection of CD14 drastically enhanced the recognition of triacylated lipopeptides by TLR2/TLR1. The CD14-induced enhancement did not occur without cotransfection of TLR1. Both CD14(dS39-A48), a mutant with deletion of the part of possible N-terminal ligand-binding pocket, and anti-CD14 monoclonal antibody reduced the CD14-induced enhancement. Transfection of a TIR domain-deficient mutant of TLR2 (TLR2(dE772-S784)) or TLR1 (TLR1(dQ636-K779)) completely abrogated the CD14-induced enhancement. Soluble recombinant CD14 added extracellularly enhanced the recognition of Pam(3)CSSNA by TLR2/TLR1. Immunoprecipitation analysis demonstrated that CD14 was not associated with TLR2 but that TLR1 was associated with TLR2. In addition, surface plasmon resonance-based assay demonstrated that CD14 binds to Pam(3)CSK(4) at a dissociation constant of 5.7 microM. This study suggests that CD14 directly binds to triacylated lipopeptides and facilitates recognition of the lipopeptides by the TLR2/TLR1 complex without binding to the receptor complex.

Cell Line↗

PubMed2006

Sublethal concentrations of diverse gold compounds inhibit mammalian cytosolic thioredoxin reductase (TrxR1).

UNLABELLED: Thioredoxin reductase (TrxR) reduces thioredoxin (Trx), thereby contributing to cellular redox balance, facilitating the synthesis of deoxy-ribose sugars for DNA synthesis, and regulating redox-sensitive gene expression. Auranofin is a gold compound that potently inhibits TrxR. This inhibition is one suspected mechanism of auranofin's therapeutic benefit in the treatment of rheumatoid arthritis. The use of other gold compounds to treat cancer or inflammatory disease may rely on their ability to inhibit TrxR. In the current study, we tested the hypothesis that a variety of gold compounds may inhibit TrxR. METHODS: We exposed rat-TrxR1 to auranofin, gold sodium thiomalate, sodium aurothiosulfate, triphenyl phosphine gold chloride, or gold acetate, and measured TrxR activity ex vivo. We then compared TrxR1 inhibitory levels of gold compounds to those that inhibited mitochondrial activity of THP1 monocytes and OSC2 epithelial cells, estimated by succinate dehydrogenase activity. RESULTS: All gold compounds inhibited TrxR1 at concentrations ranging from 5 to 4000 nM (50% inhibitory concentration). The oxidation state of gold did not correlate with inhibitory potency, but ligand configuration was important. Au(I)-phosphine compounds (triphenyl phosphine gold chloride and auranofin) were the most potent inhibitors of TrxR. All TrxR1 inhibitory concentrations were sublethal to mitochondrial activity in both THP1 and OSC2 cells. CONCLUSIONS: Diverse types of gold compounds may be effective inhibitors of TrxR1 at concentrations that do not suppress cellular mitochondrial function. Inhibition may be optimized to some degree by altering the ligand configuration of the compounds. These results support future study of a variety of Au compounds for therapeutic development as inhibitors of TrxR1.

Animals↗

PubMed2006

New concept of resin-dentin interfacial adhesion: the nanointeraction zone.

The purpose of this study was to evaluate the morphological appearance of resin-dentin interface produced by 1-step adhesive systems in order to classify them, using TEM. It was hypothesized that all interfaces produced by each 1-step adhesive show characteristics similar to that produced by the conventional self-etching system rather than that produced by etch-and-rinse system. The flattened dentin surfaces were subjected to bonding treatment using either a 2-step adhesive: single bond, mega bond, unifil bond; or a 1-step adhesive: Prompt L-Pop, absolute, xeno CF, AQ bond, one-up bond F, G bond, and SSB-200. A flowable resin was then applied to these surfaces. The results revealed that resin-dentin interfaces produced by 1-step systems were classified into three categories. Additionally, the interface produced by G bond and SSB-200 showed a different morphological appearance from that of the others. The interface produced by these adhesives was thinner and less demineralized, with the presence of hydroxyapatite-coated collagen fibrils. It is proposed that "Nanointeraction Zone (NIZ)" is a new complementary classification for partially demineralized resin-dentin interdiffusion zones. Thus, one-step self-etching adhesive systems can be classified into three categories, etch-and-rinse type, mild self-etching type, and NIZ type, by their morphological appearance of the interface.

Bisphenol A-Glycidyl Methacrylate↗

PubMed2006

Diffusion-induced water movement within resin-dentin bonds during bonding.

It is thought that water-filled channels and nanovoids in resin-dentin bonds represent potential sites for degradation of bonds or hydrolysis of collagen or both. How water gains access to bonded interfaces is not clear. This study evaluated the diffusion-induced water uptake through resin-dentin interfaces during bonding. Two light-cured total-etch adhesive systems (Excite and One-Step Plus) and a chemical-cured adhesive (Amalgambond Plus) were used in this study. Dentin disks were placed in a split-chamber device, and the fluid movement across dentin was measured, with and without a physiological pressure, during bonding procedures and 24 h after bonding. For light-cured adhesives in the experimental groups, a 6 min interval of dark storage was conducted prior to light-curing, to evaluate the diffusion of water through the uncured resin monomers, and to test the effect of prolonged infiltration time of adhesives on water permeability of bonds. Prolonged adhesive infiltration reduced the water permeability of resin-dentin bonds for light-cured adhesives. Water gradients produced by bonding systems contribute to water movement across the dentin-adhesive interfaces during bonding procedures. Differences in chemical formulations for adhesive systems may lead to differences in the extent of diffusion-induced water movement and the amount of water within the resin-dentin bonds.

Dentin↗

PubMed2006

Staining of hybrid composites with coffee, oolong tea, or red wine.

This study examined the surface staining mechanism of a photopolymerized composite by coffee, oolong tea, and red wine. Dental composite was subjected to an experimental 24-hour staining cycle: 17-hour immersion in artificial saliva solution containing 0.3% mucin followed by 7-hour immersion in coffee, tea, or wine. After one, two, and four weeks, digital images of the composite surface were analyzed in grayscale mode with an imaging analyzer. Specimens polished but not immersed were used as a baseline measurement for color change. Additionally, the effects of mechanical brushing and chlorhexidine on drink-induced staining were examined. Wine caused the most severe staining, followed by tea and coffee. After four weeks of immersion, brushing reduced surface staining by wine. On the contrary, chlorhexidine increased the staining effect of tea and coffee (p<0.05) when compared to the control specimens. In conclusion, we showed that common drinks stained the dental composite, but each by a specific mechanism that depended on external conditions such as the presence of chlorhexidine.

Acrylic Resins↗

PubMed2006

Effect of enamel shades on color of layered resin composites.

The purpose of this study was to evaluate the effect of the covering enamel layer of various thicknesses on the color of layered resin composites (LRC). To this end, the CIELAB parameters of the following were evaluated: underlying base (ULB: 2.0 mm of body shade + 3.0 mm of opaque shade), inherent color of the enamel shade (4.0 mm of enamel shade + ULB), and LRC disks (0.5, 1.0, 2.0, 3.0 mm of enamel shade + ULB) of Filtek Supreme (FS, 3M) and Gradia Direct (GD, GC). To assess the effect of the enamel layer on the color of LRC, color difference between ULB and LRC was calculated. With FS, the enamel layer had no major effect on the color of LRC--regardless of thickness. With GD, the enamel layer had a significant effect on the color of LRC, even if the thickness was only 0.5 mm. The difference in enamel layer effect between the two products could be attributed to the difference in color characteristics of the two enamel shades.

Acrylic Resins↗

PubMed2006

A newly designed automatic pH-cycling system to simulate daily pH fluctuations.

The aim of this study was to develop and evaluate an automatic pH-cycling system, which was intended for performing time-lapse analyses of dental caries. Two single-section specimens prepared from each of the five extracted human incisors were studied under a condition of 3- or 9-cycles/day for seven weeks. Increase of mineral loss (delta delta Z) and increase of Ld (delta Ld) were examined and compared at the end of every week during the study. In the 3-cycles/day condition, delta delta Z and delta Ld significantly increased only at Week 7. In the 9-cycles/day condition, delta deltaZ increased significantly from Week 5. delta Ld increased from Week 2, and then there were no further increases for the subsequent five weeks. Based on the results of this study, progression pattern was found to be significantly different between the two conditions. We therefore concluded that the automatic pH-cycling system which we have developed qualified as a model system that simulated the human oral cavity. As such, it could be beneficially employed to clarify the roles of many factors that cause or prevent caries development in human teeth.

Analysis of Variance↗

PubMed2006

Color change of newly developed esthetic restorative material immersed in food-simulating solutions.

Recently, an esthetic tooth coating material has been developed. The material consisted of a primer solution, a base coat, and a top coat. The purpose of this study, therefore, was to evaluate the color change of this tooth coating material and two resin composites after immersion in food-simulating, staining solutions. To this end, the newly developed coating material with and without its top coat, a flowable resin composite, and a hybrid resin composite were employed for the evaluation. The specimens were subjected to an experimental 24-hour staining cycle: 7-hour immersion in coffee, green tea or red wine, then 17-hour immersion in artificial saliva solution containing 0.3% mucin. After 24 hours, 3 days, 1, 2, and 4 weeks of immersion, the color changes of all specimen surfaces were measured. Compared with the other materials, the deltaE* value of coating material without its top coat tended to increase as the immersion period increased until 4 weeks. On the other hand, the deltaE* value of coating material with its top coat measured the lowest among the materials tested. Based on the results obtained, it was concluded that when using this recently developed tooth coating material in dental clinics, its top coat should be properly applied.

Coated Materials, Biocompatible↗

PubMed2006

Fluoride release and uptake by various dental materials after fluoride application.

PURPOSE: To measure the amounts of fluoride released from fluoride-containing materials before and after daily topical fluoride applications. METHODS: A conventional glass-ionomer: Fuji Ionomer Type II (F2); a resin-modified glass-ionomer: Fuji Ionomer Type II LC (LC); two "giomer" materials: Reactmer Paste (RP), and Beautifil (BT); a fluoride-containing resin composite: Unifil F (UF); and a non-fluoride resin composite: AP-X (AP) were used in this study. Each material was filled into a plastic mold, with inner diameter of 9 mm wide x 3 mm high. The specimens were stored in vials filled with 8 ml distilled deionized water for 24 hours at 37 degrees C. The specimens were then removed from the vials and the amount of fluoride released into the water, over the 24-hour period, was measured. The amount of fluoride released was measured by using specific fluoride electrode and an ion-analyzer. These procedures were repeated at Days 2, 3, 7, 14, and 21. After 21 days, all specimens were exposed to 1000 ppm F NaF solution for 5 minutes once a day. This procedure and measurement of fluoride release were continued for 14 days. After 14 days, the specimens were placed in water for 7 days and fluoride release was measured. The results were statistically analyzed using Kruskal-Wallis and Mann-Whitney U-test (P< 0.05). RESULTS: At the 22nd day (1 day after starting fluoride exposure), there was no difference between the F2 and RP, though there were significant differences between the two GICs and the groups BT and UF. After that day, there were significant differences between GIC and the group RP, BT and UF. All materials showed a decrease in fluoride release 7 days after end of the fluoride immersion period. F2, LC, and UF showed no significant difference of fluoride release between Day 21 and 1 day after the end of the fluoride immersion period (P= 0.310: F2 and UF, 0.548: LC). On the other hand, RP and BT revealed lower fluoride release 1 day after the end of the fluoride immersion period as compared to Day 21 (P= 0.075: RP, 1.000: BT). For AP, fluoride release was not detected after the fluoride immersion period.

Bisphenol A-Glycidyl Methacrylate↗

PubMed2005

The effects of common errors on sealing ability of total-etch adhesives.

OBJECTIVES: This study evaluated the effect of errors commonly made in using total-etch adhesives, on the resulting bond strength, fluid movement and nanoleakage of resin dentin bonds. METHODS: Two total-etch adhesives were used for bonding to dentin according to the manufacturers' recommendations, with meticulous solvent evaporation (control), or with the introduction of common bonding errors-wet bonding without solvent evaporation (no evaporation), and dry bonding. RESULTS: The 24-hour bond strength of the control was significantly higher than the other groups (p <0.05). For all groups, the higher initial permeability declined significantly after 24 h. The fluid movement across bonded dentin was similar in the control and dry bonding for both adhesives, whereas significantly higher permeability (p<0.05) was recorded for the no evaporation groups even after 24 h. Extensive silver impregnation within hybrid layers was seen by TEM in the no evaporation and dry bonding specimens after 24 h. Dry bonding caused collapse of the collagen matrix and interfered with resin infiltration. In contrast, inadequate solvent evaporation and/or residual water during dentin bonding results in dilution or incomplete polymerization of the resin, leading to severe nanoleakage formation. SIGNIFICANCE: Increased permeability associated with incomplete solvent evaporation in total-etch adhesives may lead to poor bond strength.

Acid Etching, Dental↗

PubMed2005

The effect of the air-blowing step on the technique sensitivity of four different adhesive systems.

PURPOSE: To evaluate the technique sensitivity of four different adhesive systems using different air-blowing pressure. METHODS: Four adhesive systems were employed: Clearfil SE Bond [SE] (Kuraray, Japan), G-Bond [GB] (GC Corporation, Japan), Adper Prompt L-Pop [LP] (3M ESPE, USA) and an experimental adhesive, SSB-200 [SSB] (Kuraray, Japan). Twenty-four extracted molars were used. After grinding the coronal enamel surface, the teeth were divided into two equal groups. The first group's teeth were randomly assigned for bonding with the different adhesives using gentle air-blowing (g). For the teeth of the second group, the four adhesive systems were applied using strong air-blowing (s). After storage overnight in 37 degrees C water, the bonded specimens were sectioned into sticks (1 mm x 1 mm wide), which were subjected to microtensile bond strength testing (microTBS) at a crosshead speed of 1 mm/min. The load at failure of each specimen was recorded and the data were analyzed by one-way ANOVA and Tukey HSD tests. The surfaces of the fractured specimens were observed using SEM to determine the failure mode. RESULTS: The results of the microTBS test showed that the highest bond strengths tended to be with SE for both gentle and strong air-blowing, and the significantly lowest for SSB with strong air streaming. Comparing the two techniques, significant differences were noted only for SSB-200 (P < 0.05). For each material, the SEM evaluation did not show distinct differences in the nature of the fractures between the two techniques, except for SSB-200. CONCLUSIONS: The adhesives tested are not technique sensitive, except SSB-200, with regards to the air-blowing step.

Air↗

PubMed2005

Effect of evaporation of primer components on ultimate tensile strengths of primer-adhesive mixture.

OBJECTIVE: The purpose of the present study was to evaluate the effect of evaporation of primer components on the ultimate tensile strength (UTS) of primer-adhesive mixtures. METHODS: The UTSs of 1:3 by weight primer-adhesive mixtures and of the pure adhesives (controls) were measured after 0-, 2-, 5-min and 24-h storage in a 37 degrees C oven for the three-step etch&rinse adhesive OptiBond FL (Kerr) and the two-step self-etch adhesive Clearfil SE (Kuraray). RESULTS: Evaporation of primer components increased with time for both adhesives investigated. OptiBond FL showed a higher evaporation of primer components than Clearfil SE at the 2-, 5-min and 24-h storage time. As compared to the pure adhesive, the UTS of the primer-adhesive mixture was lower after 0- and 2-min storage for OptiBond FL and after 0-, 2- and 5-min storage for Clearfil SE. The UTS of OptiBond FL was higher than that of Clearfil SE at the 0- and 2-min storage time, though there was no difference at the 5-min and 24-h storage time. SIGNIFICANCE: The degree of evaporation of primer components depended largely on the primer solvents employed. The significant decrease in UTS of adhesive resin when mixed with primer must be attributed to incomplete evaporation of primer components. Complete evaporation of solvents is hard to achieve, even by thorough air drying.

Adhesives↗

PubMed2005

Effect of double-application of all-in-one adhesives on dentin bonding.

OBJECTIVES: To evaluate the effect of double-application of all-in-one adhesives using the micro-shear bond test. METHODS: The occlusal surfaces of extracted human third molars were ground perpendicular to the long axis of each tooth to expose a flat dentin surface. Three commercially available and one experimental bonding system were used in this study: Adper Prompt L-Pop (APL, 3M ESPE), REACTMER BOND (RB, Shofu), XENO III (Xeno, Dentsply-Sankin) and newly developed OBF-2 (OB2, Tokuyama Dental). These adhesives were applied on the dentin surfaces by either the manufacturers' instructions or by an experimental method (single-application or double-application). Resin composite was then placed and light-cured for 40s. After 24h immersion in water, a micro-shear bond test was carried out and the fractured dentin surfaces were observed microscopically. The data were analyzed by one-way ANOVA and Tukey's HSD tests (p<0.05). RESULTS: The mean bond strengths of APL, RB, Xeno and OB2 with single-application were 22.7, 28.3, 30.3 and 34.6MPa, respectively. The mean bond strengths of APL, RB, Xeno and OB2 with double-application were 29.5, 27.2, 29.6 and 32.5MPa, respectively. There were no statistically significant differences in micro-shear bond strengths between the single- and double-application methods for each adhesive system (p>0.05). The morphological observation of the fractured dentin surfaces revealed differences between the single- and double-application groups especially for APL and OB2. CONCLUSIONS: Micro-shear bond strengths of all-in-one adhesives in this study showed no statistically significant differences between the single-application and the double-application method.

Analysis of Variance↗

PubMed2005

Permeability of adhesive resin films.

The purpose of this study was to quantify the permeability of adhesive resin films to water by measuring convective flow across thin films. Cured resin films were prepared with the use of five commercially available adhesive resins and an experimental resin. Two types of resin films were prepared from solvated comonomer blends within each product; resin films made before or after evaporation of solvent (10 s of drying with air-syringe). The permeability of the resin films was measured 30 min or 24 h after polymerization by placing the films in a split-chamber device. Fluid filtration rate through the resin films was measured with the use of 20 cm of water pressure. Osmotically induced water movement was measured by applying hypertonic aqueous solutions of CaCl2 or HEMA to the resin films. The results showed that evaporation of solvent before polymerization reduced the permeability of adhesive resin films, compared to permeabilities obtained without solvent evaporation. The cured adhesive resin films were all permeable to water, but to varying degrees.

Adhesives↗

PubMed2005

Effect of fracture strength of primer-adhesive mixture on bonding effectiveness.

OBJECTIVE: The purpose of this study was to measure the micro-tensile bond strength (microTBS) of two adhesives to dentin and to correlate this microTBS with the micro-tensile fracture strength (microTFS) of primer-adhesive mixtures of the two adhesives. METHODS: The three-step etch&rinse adhesive OptiBond FL (Kerr) and the two-step self-etch adhesive Clearfil SE Bond (Kuraray) were used to bond Filtek Z100 (3M ESPE) to twenty mid-coronal dentin surfaces. The microTBS was determined at 1 and 24 h after light-curing. In addition, the microTFS of primer-adhesive mixtures (primer:adhesive=1:3 by weight) and of the pure adhesives (controls) were measured after the same time intervals. RESULTS: The microTBS to dentin of OptiBond FL at 24 h was significantly higher than at 1 h and than the microTBS of Clearfil SE Bond at 24 h. The mean microTFS of the primer-adhesive mixtures was always lower than the microTFS of the respective adhesives. The highest reduction in microTFS due to mixing primer with the adhesive resin was measured for Clearfil SE Bond. Both the microTFS of the primer-adhesive mixtures and the pure adhesives of OptiBond FL and Clearfil SE Bond increased with time. SIGNIFICANCE: The early 1 h microTBS to dentin was lower than the 24 h microTBS for OptiBond FL, but not for Clearfil SE Bond. Differences in polymerization efficiency as well as in the resulting interfacial strength may explain such varying early bond strengths to dentin.

Composite Resins↗

PubMed2005

Colour and translucency of opaque-shades and body-shades of resin composites.

The purpose of this study was to evaluate the optical properties--not only the translucency but also the colours--of opaque-shade resin composites. The CIELAB parameters (L*, a* and b*) of disks of A2 and opaque A2 (OA2) shades of Charisma (Heraeus-Kulzer), Solare (GC) and Filtek Supreme (3M) were evaluated on backings of black, white and the material itself to calculate the translucency parameter (TP) and the colour differences (delta E*) between A2 and OA2. A two-way analysis of variance (anova) for the TP indicated a less statistically significant TP value in the OA2 shade than the A2 shade for all products. As for the products, Charisma showed a statistically greater TP value than the other two products. Regarding the delta E* between A2 and OA2, all the products revealed clinically perceptible colour differences (delta E* > 3.3). Hence, we must take the colour differences of opaque-shade resin composites into consideration, as well as the translucency of the materials, for a clinically acceptable colour match of the restoration.

Color↗