- Acceleration of curing of resin composite at the bottom surface using slow-start curing methods.
Acceleration of curing of resin composite at the bottom surface using slow-start curing methods.
Dent Mater J. 2013 Nov 15;
Authors: Yoshikawa T, Morigami M, Sadr A, Tagami J
The aim of this study was to evaluate the effect of two slow-start curing methods on acceleration of the curing of resin composite specimens at the bottom surface. The light-cured resin composite was polymerized using one of three curing techniques: (1) 600 mW/cm(2) for 60 s, (2) 270 mW/cm(2) for 10 s+0-s interval+600 mW/cm(2) for 50 s, and (3) 270 mW/cm(2) for 10 s+5-s interval+600 mW/cm(2) for 50 s. After light curing, Knoop hardness number was measured at the top and bottom surfaces of the resin specimens. The slow-start curing method with the 5-s interval caused greater acceleration of curing of the resin composite at the bottom surface of the specimens than the slow-start curing method with the 0-s interval. The light-cured resin composite, which had increased contrast ratios during polymerization, showed acceleration of curing at the bottom surface.
PMID: 24240907 [PubMed - as supplied by publisher]
- Polymerization behavior within adhesive layer of one- and two-step self-etch adhesives: A micro-Raman spectroscopic study.
Polymerization behavior within adhesive layer of one- and two-step self-etch adhesives: A micro-Raman spectroscopic study.
Dent Mater J. 2013 Nov 15;
Authors: Sakano W, Nakajima M, Prasansuttiporn T, M Foxton R, Tagami J
This study investigated the polymerization behavior within the adhesive layer of one- and two-step self-etch adhesives at the dentincomposite interface. Dentin surfaces were applied with Clearfil S(3) Bond (TS), Clearfil S(3) Bond Plus (TSP) and Clearfil SE Bond (SE), and then placed with a light-curing resin composite. After water storage for 24 h, the bonded teeth were sectioned and polished perpendicular to the adhesive interface, and the degree of conversion (DC) of the adhesive layer between the dentin and composite were determined using micro-Raman analysis. For all the adhesives, the DCs of the adhesive layers significantly decreased near the adhesive-composite join (p<0.05). For the maximum DC value (Pmax) and the DC value at the adhesive-composite join (Pitf), TS was significantly lower than TSP and SE (p<0.05). The polymerization of oxygen-inhibited layer at the top of the adhesive could not reach maximum DC even after polymerization of the overlying resin composite.
PMID: 24240894 [PubMed - as supplied by publisher]
- The effect of glutathione on 2-hydroxyethylmethacrylate cytotoxicity and on resin-dentine bond strength.
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The effect of glutathione on 2-hydroxyethylmethacrylate cytotoxicity and on resin-dentine bond strength.
Int Endod J. 2013 Oct 9;
To evaluate the influence of reduced glutathione (GSH) application on 2-hydroxyethylmethacrylate (HEMA) cytotoxicity on rat pulpal cells and evaluate the effect of etched-dentine treatment with GSH on the immediate microtensile bond strength (μTBS) of etch-and-rinse adhesive.
The cytotoxicity of 10 mmol L-1 HEMA, 10 mmol L-1 HEMA + 1 mmol L-1 GSH, 10 mmol L-1 HEMA + 5 mmol L-1 GSH and 10 mmol L-1 HEMA + 10 mmol L-1 GSH was compared (6 h and 24 h). Cells viability was measured by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, followed by morphological observation of cells. Etched-dentine surfaces were rinsed and treated with one of the following solutions: 2% GSH, 5% GSH or 10% GSH, bonded with Adper Single Bond Plus (3M, ESPE, St. Paul, MN, USA) and restored with resin composite. The control group received no GSH treatment. After 1 day of water-storage at 37 °C, the specimens were subjected to μTBS testing. Cytotoxicity and μTBS data were analysed by one-way anova and Tukey post hoc tests (P < 0.05).
There were significant differences between the groups. HEMA elicited a remarkable toxic effect. 10 mmol L-1 GSH prevented HEMA-induced damage at both exposure times. Whilst 5 mmol L-1 GSH lost its protective effect at 24-h exposure time and 1 mmol L-1 GSH showed no protective effect at both exposure times, GSH had no significant effect on the immediate μTBS; however, 5% GSH had higher bond strength value when compared to 10% GSH (P = 0.003).
Controlled concentrations of GSH had a protective effect against HEMA cytotoxicity. GSH had neither positive nor negative influence on μTBS.
PMID: 24117849 [PubMed - as supplied by publisher]
- Effects of solvent drying time on mass change of three adhesives.
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Effects of solvent drying time on mass change of three adhesives.
J Conserv Dent. 2013 9;16(5):418-422
AIM: Adhesives may change their mass due to water sorption or dilution of components after curing. The aim of this study was to evaluate the influence of air-drying time and water storage on mass changes (MC) of three adhesives; Adper Single Bond2 (ASB), One-step plus (OSP), Clearfil S(3) Bond (CSB).
MATERIALS AND METHODS: Rectangular-shape samples from each adhesive were prepared and cured for 120 s with a halogen light curing unit. Prior to curing, their solvent was evaporated by means of three different procedures depending on the passive air-drying time (i.e., no air drying, equal to active air drying, complete evaporation after 3 h). Each group was further divided into two subgroups based on the time of water storage (1-day, 7-days), prior to measurement of MC (n = 10). The data were analyzed using a three-way ANOVA.
RESULTS: Adhesives showed different patterns of MC in relation to air drying and water storage; (P < 0.05). In OSP and CSB with increasing water storage and air drying, the MC increased significantly (P < 0.01).
CONCLUSION: The highest MC in the etch-and-rinse adhesives was observed when the adhesive was not dried, while in the self-etch adhesive the highest changes were observed when the adhesive was completely dried.
PMID: 24082570 [PubMed - as supplied by publisher]
- In vitro evaluation of plant-derived agents to preserve dentin collagen.
In vitro evaluation of plant-derived agents to preserve dentin collagen.
Dent Mater. 2013 Aug 10;
Authors: Hiraishi N, Sono R, Sofiqul I, Yiu C, Nakamura H, Otsuki M, Takatsuka T, Tagami J
OBJECTIVE: Biomodification of dentin by a natural crosslinker has been recommended to improve a mechanical property of demineralized dentin. This study investigated the effect of various plant-derived agents (hesperidin, proanthocyanidin, epigallocatechin gallate and genipin) on the stability of dentin collagen matrix to resist collagenase degradation.
METHODS: The dentin specimens were treated with glutaraldehyde (0.5% and 5.0%) and each plant-derived test solution (0.5%). They were subjected to ultimate tensile strength (UTS) and swelling ratio measurements. Demineralized human dentin powder was incubated with 0.02%, 0.1% and 0.5% of each test agent and followed by bacterial collagenase digestion. The extent of collagen degradation was investigated using hydroxyproline assay.
RESULTS: The UTS and swelling ratio measurements revealed that the mechanical property of dentin was improved by the use of these natural agents. The greatest reduction in collagen degradation was shown following the use of hesperidin, proanthocyanidin, and epigallocatechin gallate at 0.5%.
SIGNIFICANCE: The use of hesperidin, proanthocyanidin, and epigallocatechin gallate could improve the mechanical properties of collagen and resist enzymatic degradation, leading to functional repair of pathological dentin lesion.
PMID: 23942145 [PubMed - as supplied by publisher]
- The importance of size-exclusion characteristics of type I collagen in bonding to dentin matrices.
The importance of size-exclusion characteristics of type I collagen in bonding to dentin matrices.
Acta Biomater. 2013 Aug 5;
Authors: Takahashi M, Nakajima M, Tagami J, Scheffel DL, Carvalho RM, Mazzoni A, Carrilho M, Tezvergil-Mutluay A, Breschi L, Tjäderhane L, Jang SS, Tay FR, Agee KA, Pashley DH
The mineral phase of dentin is located primarily within collagen fibrils. During development, bone or dentin collagen fibrils are formed first and then water within the fibril is replaced with apatite crystallites. Mineralized collagen contains very little water. During dentin bonding, acid-etching of mineralized dentin solubilizes the mineral crystallites and replaces them with water. During the infiltration phase of dentin bonding, adhesive comonomers are supposed to replace all of the collagen water with adhesive monomers that are then polymerized into copolymers. The authors of a recently published review suggested that dental monomers were too large to enter and displace water from collagen fibrils. If that were true, the endogenous proteases bound to dentin collagen could be responsible for unimpeded collagen degradation that is responsible for the poor durability of resin-dentin bonds. The current work studied the size-exclusion characteristics of dentin collagen, using a gel-filtration-like column chromatography technique, using dentin powder instead of Sephadex. The elution volumes of test molecules, including adhesive monomers, revealed that adhesive monomers smaller than about 1000 Da can freely diffuse into collagen water, while molecules of 10,000 Da begin to be excluded, and bovine serum albumin (66,000 Da) was fully excluded. These results validate the concept that dental monomers can permeate between collagen molecules during infiltration by etch-and-rinse adhesives.
PMID: 23928333 [PubMed - as supplied by publisher]
- Effect of a calcium-phosphate based desensitizer on dentin surface characteristics.
Effect of a calcium-phosphate based desensitizer on dentin surface characteristics.
Dent Mater J. 2013;32(4):615-21
Authors: Thanatvarakorn O, Nakashima S, Sadr A, Prasansuttiporn T, Thitthaweerat S, Tagami J
This study aimed to evaluate the ability of a newly developed calcium-phosphate desensitizer in dentin permeability reduction and its integration with dentin surface before and after immersion in artificial saliva (AS) under two different dentin surface characteristics; with or without the collagen exposure.Humandentin discs treated by EDTA to expose collagen fibrils or EDTA/NaOCl to expose plain dentin surface were subjected to a calcium-phosphate desensitizer (Teethmate Desensitizer; TMD), while non-desensitizer treatment served as control. TMD application showed the occlusion in dentinal tubules and reduction in dentin permeability up to 92%, regardless of dentin surface characteristics. After AS immersion, permeability reduction percent (PR%) significantly increased in EDTA/NaOCl pretreatment (p<0.05). Newly-formed crystallites were observed on desensitizer treated dentin and EDTA/NaOCl pretreatment control group, whereas the crystallites did not exist on EDTA pretreatment control group. Ultrasonication revealed the integration of the calcium-phosphate rich layer of desensitizer on dentin surface after AS immersion.
PMID: 23903644 [PubMed - in process]
- Effect of fluoride concentration in adhesives on morphology of acid-base resistant zones.
Effect of fluoride concentration in adhesives on morphology of acid-base resistant zones.
Dent Mater J. 2013;32(4):578-84
Authors: Kirihara M, Inoue G, Nikaido T, Ikeda M, Sadr A, Tagami J
This study aimed to investigate the effect of fluoride concentration in adhesives on morphology of acid-base resistant zone (ABRZ). Seven experimental adhesives with different concentrations of NaF (0 wt%; F0 to 100 wt%: F100) were prepared based on the formulation of a commercially available adhesive (Clearfil Protect Bond, F100). The resin-dentin interface of the bonded specimen was subjected to demineralizing solution and NaOCl, sectioned, polished and argon-ion etched for SEM observation. Fluoride release from each adhesive was measured using an ion-selective electrode. Fluoride ion release from the adhesive linearly increased with higher NaF concentration. The ABRZ area increased significantly with higher NaF concentration except for F0, F10, and F20 (p<0.05). F100 showed the largest ABRZ, where a slope of acid-resistant dentin was clearly observed at the bottom of the ABRZ. The concentration of NaF in the two-step self-etching adhesive resin influenced the amount of dentin structure remaining after acid-challenge.
PMID: 23903639 [PubMed - in process]
- Relationship between perception of difficulty and clinical experience of approximal composite restorations in final-year undergraduate students at Tokyo Medical and Dental University.
Related Articles on PubMed
Relationship between perception of difficulty and clinical experience of approximal composite restorations in final-year undergraduate students at Tokyo Medical and Dental University.
J Med Dent Sci. 2011;58(1):1-5
Authors: Kitasako Y, Sadr A, Nikaido T, Tagami J
The aims of this study were to clarify which steps in approximal restorative procedure were difficult for the final-year undergraduate students at Tokyo Medical and Dental University, and to examine the relationship between perception of difficulty and clinical experience. At mid-term of the clinical education experience, a self-questionnaire was performed by final-year undergraduate students to clarify the difficulty of restorative procedures at the time. There were statistically significant differences in the number of clinical cases experienced at the time between students who designated the matrix application, shade selection and finishing as the easy steps and those who considered them as the difficult ones (Fisher exact test with Bonferroni correction, p < 0.05). There was a significant difference in the total number of procedures designated as difficult between students who had treated above 15 cases and those who had fewer than 15 cases (Wilcoxon rank-sum test, p< 0.05). In the final-year clinical education for operative dentistry, students might need to treat over 15 cases to gain confidence in performing approximal composite restorations independently.
PMID: 23896780 [PubMed - as supplied by publisher]
- Nondestructive assessment of current one-step self-etch dental adhesives using optical coherence tomography.
Related Articles on PubMed
Nondestructive assessment of current one-step self-etch dental adhesives using optical coherence tomography.
J Biomed Opt. 2013 Jul 1;18(7):76020
Authors: Bista B, Sadr A, Nazari A, Shimada Y, Sumi Y, Tagami J
ABSTRACT. This study aimed to nondestructively evaluate sealing performance of eight one-step self-etch adhesives (1-SEAs) using optical coherence tomography (OCT). The two-step self-etch adhesive (2-SEA) served as the control. Round tapered class-I cavities (D=4 mm, H=2 mm) were prepared in bovine incisors, treated with each adhesive (n=5), and restored with a flowable resin composite. Cross-sections were obtained from each restoration using swept-source OCT with 1310-nm laser. The average percentage of the sealed interface (SI%) for each adhesive was calculated using image analysis software, considering increased signal intensity at the interface as gap. Samples were then sectioned and observed under confocal laser scanning microscope (CLSM). Significantly different SI% values were found among different adhesives (analysis of variance, Bonferroni, p<0.05). There was also a significant correlation in SI% between OCT and CLSM (p<0.0001, r=0.96). Additionally, microscopic analysis revealed that the gaps in 1-SEAs occurred not only at dentine-adhesive interfaces but also frequently at adhesive-composite interfaces. Some recent 1-SEAs could achieve reliable short-term sealing comparable to 2-SEA. OCT is a unique tool to nondestructively evaluate the sealing performance of the restoratives through the cavity, provided that cavity walls have a certain minimum inclination with respect to the beam.
PMID: 23887479 [PubMed - in process]
- Effect of phytic acid used as etchant on bond strength, smear layer, and pulpal cells.
Related Articles on PubMed
Effect of phytic acid used as etchant on bond strength, smear layer, and pulpal cells.
Eur J Oral Sci. 2013 Jun 20;
Authors: Nassar M, Hiraishi N, Islam MS, Aizawa M, Tamura Y, Otsuki M, Kasugai S, Ohya K, Tagami J
This study aimed to evaluate the effect of phytic acid (IP6), used as etchant, on resin-dentin bond strength, smear layer removal, and the viability of pulpal cells. Flat dentin surfaces with smear layer were etched with 1% IP6 for 60, 30, or 15 s; in the control group 37% phosphoric acid (PA) was used. Dentin surfaces were rinsed, blot-dried, and bonded with an etch-and-rinse adhesive, followed by composite build-ups. The specimens were subjected to tensile testing after 24 h of water storage at 37°C, and failure modes were determined using scanning electron microscopy. The effectiveness of IP6 to remove the smear layer was observed using scanning electron microscopy. To evaluate the effect on pulpal cells, solutions of 0.1 and 0.01% IP6 and of 3.7 and 0.37% PA were prepared and rat pulpal cells were treated with these solutions for 6 and 24 h. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results demonstrated that all application times of IP6 produced bond-strength values that were significantly higher than that of the control. Phytic acid effectively removed the smear layer and plugs, thus exposing the collagen network. Phytic acid had a minimal effect on pulpal cells, whereas PA resulted in a marked decrease in their viability.
PMID: 23879874 [PubMed - as supplied by publisher]
- Mussel-mimetic, bioadhesive polymers from plant-derived materials.
Mussel-mimetic, bioadhesive polymers from plant-derived materials.
J Investig Clin Dent. 2013 Jul 16;
Authors: Hiraishi N, Kaneko D, Taira S, Wang S, Otsuki M, Tagami J
AIM: Mussel-mimetic, bioadhesive polymers are synthesized from plant-derived sources. The strong adhesive action is caused by interactions between the catechol groups at the end of the polymer terminal chains and the substrate surface. Here, we present a preliminary study of the adhesion properties and a discussion of the adhesion mechanism.
METHODS: Two bioadhesive polymers were synthesized from natural plant-derived monomers by the transesterification of: (a) caffeic acid (3,4-dihydroxycinnamic acid; DHCA) and p-coumaric acid (4-hydroxycinnamic acid; 4HCA) to produce poly(DHCA-co-4HCA); and (b) 4-dihydroxyhydrocinnamic acid (DHHCA) and 3-(3-hydroxyphenyl) propionic acid (3HPPA) to produce poly(DHHCA-co-3HPPA). Thermoplastic poly(DHCA-co-4HCA) or poly(DHHCA-co-3HPPA) was placed between glass, carbon, steel, or bovine dentin substrates, and a lap shear adhesion test was conducted to compare them using conventional cyanoacrylate glue and epoxy resin.
RESULTS: The greatest adhesion for all tested substrates was exhibited by poly(DHHCA-co-3HPPA), followed by epoxy resin adhesive, poly(DHCA-co-4HCA), and cyanoacrylate adhesive. The adhesive strength of poly(DHHCA-co-3HPPA) was greater than 25.6 MPa for glass, 29.6 MPa for carbon, 15.7 MPa for steel, and 16.3 MPA for bovine dentin.
CONCLUSION: The adhesion of poly(DHHCA-co-3HPPA) might be the strongest reported for a mussel-mimic adhesive system, and could be a feasible alternative to petroleum adhesives.
PMID: 23857900 [PubMed - as supplied by publisher]
- Combined effect of smear layer characteristics and hydrostatic pulpal pressure on dentine bond strength of HEMA-free and HEMA-containing adhesives.
Related Articles on PubMed
Combined effect of smear layer characteristics and hydrostatic pulpal pressure on dentine bond strength of HEMA-free and HEMA-containing adhesives.
J Dent. 2013 Jul 11;
Authors: Mahdan MH, Nakajima M, Foxton RM, Tagami J
OBJECTIVE: This study evaluated the combined effect of smear layer characteristics with hydrostatic pulpal pressure (PP) on bond strength and nanoleakage expression of HEMA-free and -containing self-etch adhesives.
METHODS: Flat dentine surfaces were obtained from extracted human molars. Smear layers were created by grinding with #180- or #600-SiC paper. Three HEMA-free adhesives (XenoV, G Bond Plus, Beautibond Multi) and two HEMA-containing adhesives (Bond Force, Tri-S Bond) were applied to the dentine surfaces under hydrostatic PP or none. Dentine bond strengths were determined using the microtensile bond test (μTBS). Data were statistically analyzed using three- and two-way ANOVA with Tukey post-hoc comparison test. Nanoleakage evaluation was carried out under a scanning electron microscope (SEM).
RESULTS: Coarse smear layer preparation and hydrostatic PP negatively affected the μTBS of HEMA-free and -containing adhesives, but there were no significant differences. The combined experimental condition significantly reduced μTBS of the HEMA-free adhesives, while the HEMA-containing adhesives exhibited no significant differences. Two-way ANOVA indicated that for HEMA-free adhesives, there were significant interactions in μTBS between smear layer characteristics and pulpal pressure, while for HEMA-containing adhesives, there were no significant interactions between them. Nanoleakage formation within the adhesive layers of both adhesive systems distinctly increased in the combined experimental group.
CONCLUSION: The combined effect of coarse smear layer preparation with hydrostatic PP significantly reduced the μTBS of HEMA-free adhesives, while in HEMA-containing adhesives, these effects were not obvious. Clinical significance: Smear layer characteristics and hydrostatic PP would additively compromise dentine bonding of self-etch adhesives, especially HEMA-free adhesives.
PMID: 23851133 [PubMed - as supplied by publisher]
- Effects of curing mode and moisture on nanoindentation mechanical properties and bonding of a self-adhesive resin cement to pulp chamber floor.
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Effects of curing mode and moisture on nanoindentation mechanical properties and bonding of a self-adhesive resin cement to pulp chamber floor.
Dent Mater. 2013 Apr 19;
Authors: Moosavi H, Hariri I, Sadr A, Thitthaweerat S, Tagami J
OBJECTIVE: This study aimed to investigate the effect of dentin surface moisture and curing mode on microtensile bond strength (MTBS) and nanoindentation characteristics of a self-adhesive resin cement. METHODS: Forty-four extracted human molars were distributed into four groups according to dentin surface moisture (dry or wet) and curing mode of the resin cement (light or chemical). Clearfil SA Cement (Kuraray Noritake Dental, Japan) was used for cementation of composite cores to the pulp chamber dentin. The specimens were sectioned into beams for MTBS test at the pulpal floor. Nanoindentation hardness and creep of the cement layer were measured under 100mN load with 30s hold segment. Data were statistically analyzed using two-way ANOVA and Weibull distribution of MTBS (α=0.05). RESULTS: Moisture, curing mode or their interaction did not significantly affect mean MTBS values that ranged 17.6-22.6MPa (p>0.05); however, the lowest characteristic strength was found in moist chemically cured group. Hardness ranged 437-512MPa, and was not affected by the experimental factors (p>0.05). Nanoindentation creep ranged 9.3-10.9% with the chemically cured groups showing the highest values, indicating lower cross-linking and deformation resistance of their polymer network. SIGNIFICANCE: Additional moisture on dentin surface did not contribute to adhesion of the anhydrous self-adhesive resin cement to dentin. Light-curing, despite attenuation through the composite core, was beneficial and improved nanoindentation creep resistance of the cement. The difference was not, however, reflected in the mean bond strength or hardness values.
PMID: 23608759 [PubMed - as supplied by publisher]
- Monitoring remineralization of enamel subsurface lesions by optical coherence tomography.
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Monitoring remineralization of enamel subsurface lesions by optical coherence tomography.
J Biomed Opt. 2013 Apr 1;18(4):46006
Authors: Mandurah MM, Sadr A, Shimada Y, Kitasako Y, Nakashima S, Bakhsh TA, Tagami J, Sumi Y
ABSTRACT. Optical coherence tomography (OCT) is a potential clinical tool for enamel lesion monitoring. Swept-source OCT findings were compared with cross-sectional nanohardness findings of enamel. Subsurface bovine enamel lesions in three groups were subjected to (1) deionized water (control), (2) phosphoryl oligosaccharide of calcium (POs-Ca) or (3) POs-Ca with 1 ppm fluoride for 14 days. B-scans images were obtained at 1310-nm center wavelength on sound, demineralized and remineralized areas after 4, 7, and 14 days. The specimens were processed for cross-sectional nanoindentation. Reflectivity from enamel that had increased with demineralization decreased with remineralization. An OCT attenuation coefficient parameter (μt), derived based on the Beer-Lambert law as a function of backscatter signal slope, showed a strong linear regression with integrated nanohardness of all regions (p<0.001, r=-0.97). Sound enamel showed the smallest, while demineralized enamel showed the highest μt. In group three, μt was significantly lower at four days than baseline, but remained constant afterwards. In group two, the changes were rather gradual. There was no significant difference between groups two and three at 14 days in nanohardness or μt POs-Ca with fluoride-enhanced nanohardness of the superficial zone. OCT signal attenuation demonstrated a capability for monitoring changes of enamel lesions during remineralization.
PMID: 23563920 [PubMed - in process]
- Cariotester, a new device for assessment of dentin lesion remineralization in vitro.
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Cariotester, a new device for assessment of dentin lesion remineralization in vitro.
Dent Mater J. 2013;32(2):241-7
Authors: Utaka S, Nakashima S, Sadr A, Ikeda M, Nikaido T, Shimizu A, Tagami J
This study aimed to evaluate the potential of a new device (Cariotester) for monitoring of incipient carious lesion remineralization in root dentin by topical fluoride in vitro. Demineralized bovine dentin specimens were treated by fluoride solutions (APF or neutral NaF) and remineralized for 4 weeks. Cariotester was used to measure penetration depth (CTR depth) of the indenter into the de- and remineralized specimen surface. The specimens were assessed by transverse microradiography (TMR) to determine lesion parameters (depth: LD, mineral loss: ΔZ). Pearson’s correlation analysis showed an overall significant relationship between CTR depth and both TMR parameters. CTR depth appeared to distinguish the positive effect that topical fluoride application had on the remineralization of the outer zone of dentin lesions. Cariotester had the potential to serve as a quantitative tool for monitoring of incipient carious lesion remineralization in root dentin.
PMID: 23538759 [PubMed - in process]
- Development and evaluation of a low-erosive apple juice drink with Phosphoryl-Oligosaccharides of Calcium.
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Development and evaluation of a low-erosive apple juice drink with Phosphoryl-Oligosaccharides of Calcium.
Dent Mater J. 2013;32(2):212-8
Authors: Mita H, Kitasako Y, Takagaki T, Sadr A, Tagami J
This study aimed to evaluate effectiveness of Phosphoryl-Oligosaccharides of Calcium (POs-Ca) added to apple juice on enamel erosion. Five juices were prepared by adding 0%, 0.5%, 1%, 1.5% or 2% POs-Ca to commercial apple juice, and subjected to Visual Analogue Scale (VAS) taste evaluation and pH and calcium/inorganic-phosphates analyses. To evaluate erosion, polished bovine enamel blocks were immersed in each juice for 5 or 60 min (n=20). Enamel surface loss (SL) and roughness (Ra) were also analyzed. VAS indicated acceptable taste for juices containing up to 1% POs-Ca. POs-Ca addition resulted in increased pH (3.61-3.88), calcium (0.95-25.10 mM), and inorganic-phosphate (1.77-20.44 mM). After 5 min, 0% juice resulted in significant erosion (p<0.05). However even after 60 min, no significant increase was found in Ra and SL compared to water (control) for 1.5-2% juices (p>0.05). Addition of 1-1.5% POs-Ca could significantly reduce enamel erosion by apple juice maintaining an acceptable taste.
PMID: 23538755 [PubMed - in process]
- 3D Assessment of Void and Gap Formation in Flowable Resin Composites Using Optical Coherence Tomography.
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3D Assessment of Void and Gap Formation in Flowable Resin Composites Using Optical Coherence Tomography.
J Adhes Dent. 2012 Nov 12;
Authors: Nazari A, Sadr A, Shimada Y, Tagami J, Sumi Y
Purpose: To investigate the effect of composite type and cavity size on gap and void formation using optical coherence tomography (OCT). Materials and Methods: Class I cavities of two depths (2 mm or 4 mm; 4 mm diameter) were prepared, treated with Tri-S Bond (Kuraray Medical), and bulk filled with either Surefil SDR Flow (SF; Dentsply) or Clearfil Majesty LV (MJ; Kuraray Medical) to form four groups. After 24 h, the specimens were 3D scanned using swept-source OCT (Santec) with 1310 nm laser at a 20 kHz sweep rate. In OCT tomograms, the bonding interface and the bulk of the restorations were evaluated. The percentage values of sealed interfaces (SP) and void volume (VP) for all groups were calculated and statistically analyzed using two- and one-way ANOVA and Tukey’s post-hoc test. Selected specimens were cross sectioned and observed using a scanning electron microscope (SEM) and a confocal laser scanning microscope to confirm OCT findings. Results: The following values were obtained for SP and VP, respectively: SF-2mm: 92% and 0.08%; SF-4mm: 66% and 0.13%; MJ-2mm: 86% and 1.79%; MJ-4mm: 33% and 1.96%. Both composites showed a significant increase in gap formation at 4-mm cavity depth (p < 0.001). While SF showed a rather homogeneous bulk compared to MJ, cavity depth did not significantly affect the void volume fraction (p = 0.08). Conclusion: The flowable composite with SDR (stress-decreasing resin) technology performed better than the conventional composite; however, bulk filling a 4-mm-deep cavity will compromise the sealing of the bonding interface regardless of the type of composite. OCT is a unique method of characterizing materials and their behaviors nondestructively and precisely.
PMID: 23534012 [PubMed - as supplied by publisher]
- Effect of solvent evaporation strategies on regional bond strength of one-step self-etch adhesives to root canal dentine.
Related Articles on PubMed
Effect of solvent evaporation strategies on regional bond strength of one-step self-etch adhesives to root canal dentine.
Int Endod J. 2013 Feb 23;
Authors: Thitthaweerat S, Nakajima M, Foxton RM, Tagami J
AIM: To evaluate the efficacy of different solvent evaporation strategies on bonding of one-step self-etch adhesives to root canal dentine. METHODOLOGY: Two dual-cure resin core systems (Clearfil DC Bond/Clearfil DC Core Automix and Clearfil Tri-S Bond Plus/Clearfil DC Core Plus; Kuraray Noritake Dental, Tokyo, Japan) were equally applied in 24 post spaces from extracted human mandibular premolars. After the adhesive application, specimens were randomly assigned into four water/solvent evaporation strategies as follows (I) insertion of absorbent paper point for 10 s: P, (II) 10 s air-blowing: A, (III) as (II) followed by insertion of absorbent paper point: AP, (IV) as (III) followed by 10 s additional air-blowing: APA. Then, the adhesives were light cured, and resin core materials were placed into the post space, followed by light curing for 60 s. After water storage for 24 h, 0.6 × 0.6 mm-thick beams were prepared to measure the regional μTBS. The mode of failure was also observed. The μTBS values were statistically analysed using three-way anova and Duncan HSD test (α = 0.05). RESULTS: In the coronal region, there were no significant differences in μTBS between each evaporation strategy (P > 0.05), except P group. However, in the apical region, APA and AP groups significantly increased in μTBS compared with A and P groups (P < 0.05). Only in the APA group of Clearfil Tri-S Bond Plus/Clearfil DC Core Plus, was there no significant difference in μTBS between the coronal and apical regions (P > 0.05). CONCLUSION: The use of paper points with additional air-blowing for removing excessive adhesive and evaporating residual water/solvent would be effective in producing higher bond strength for the tested one-step self-etch adhesives and fewer blister formations in deeper regions of the post space.
PMID: 23521044 [PubMed - as supplied by publisher]
- Noninvasive cross-sectional imaging of proximal caries using swept-source optical coherence tomography (SS-OCT) in vivo.
Noninvasive cross-sectional imaging of proximal caries using swept-source optical coherence tomography (SS-OCT) in vivo.
J Biophotonics. 2013 Mar 1;
Authors: Shimada Y, Nakagawa H, Sadr A, Wada I, Nakajima M, Nikaido T, Otsuki M, Tagami J, Sumi Y
The aim of this study was to determine the diagnostic accuracy of swept-source optical coherent tomography (SS-OCT) in detecting and estimating the depth of proximal caries in posterior teeth in vivo. SS-OCT images and bitewing radiographs were obtained from 86 proximal surfaces of 53 patients. Six examiners scored the locations according to a caries lesion depth scale (0-4) using SS-OCT and the radiographs. The results were compared with clinical observations obtained after the treatment. SS-OCT could detect the presence of proximal caries in tomograms that were synthesized based on the backscatter signal obtained from the proximal carious lesion through occlusal enamel. SS-OCT showed significantly higher sensitivity and larger area under the receiver operating characteristic curve than radiographs for the detection of cavitated enamel lesions and dentin caries (Student’s t -test, p < 0.05). SS-OCT appears to be a more reliable and accurate method than bitewing radiographs for the detection and estimation of the depth of proximal lesions in the clinical environment. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).
PMID: 23450799 [PubMed - as supplied by publisher]
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