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Junji Tagami - One of the best experts on this subject based on the ideXlab platform.
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effects of a Surface prereacted glass ionomer filler coating material on biofilm formation and inhibition of Dentin demineralization
Clinical Oral Investigations, 2021Co-Authors: Shiori Yamamoto, Khairul Matin, Toru Nikaido, Noriko Hiraishi, Mahmoud Sayed, Motoi Takahashi, Michael F Burrow, Junji TagamiAbstract:This study investigated the ability of a Surface prereacted glass–ionomer (S-PRG) coating material to inhibit the biofilm formation and demineralization of Dentin. Dentin specimens were randomly divided into three groups: (1) no coating (control), (2) S-PRG filler-containing coat, and (3) a nonS-PRG filler–containing coat. Streptococcus mutans biofilms were grown on the Dentin Surfaces in a microcosm for 20 h. Then, the quantity of bacteria and water-insoluble glucan in the retained biofilm on the Dentin Surface were measured. Regarding demineralization inhibition test, specimens were demineralized for 5 days then sectioned into halves and observed under confocal laser scanning microscope (CLSM). One-way ANOVA and Tukey’s HSD were used for statistical analysis. The estimated mean Surface roughness for specimens in the S-PRG group was statistically significantly higher than the estimates for both the nonS-PRG and the control group specimens. The quantity of bacteria and water-insoluble glucan/mm2 revealed that the S-PRG group prevented biofilm formation and bacterial adhesion to the Dentin Surface compared with the control and nonS-PRG groups. The S-PRG group recorded the highest acid-resistance ability with no Surface loss. Application of S-PRG barrier coat on Dentin Surfaces can inhibit biofilm formation as well as protecting the Dentin Surface against demineralization. Coating material containing S-PRG fillers might be used for caries prevention, through inhibiting biofilm formation, enhancing mineralization, and reducing acidic attack by cariogenic bacteria.
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smear layer deproteinization improving the adhesion of self etch adhesive systems to caries affected Dentin
Current Oral Health Reports, 2018Co-Authors: Keiichi Hosaka, Taweesak Prasansuttiporn, Ornnicha Thanatvarakorn, Richard M Foxton, Junji Tagami, Sitthikorn Kunawarote, Masahiro Takahashi, Masatoshi NakajimaAbstract:This paper reviews a new method of Dentin Surface modification, smear layer-deproteinization for self-etch adhesive systems, particularly in relation to improving the adhesion to caries-affected Dentin. Remnants of smear debris, which forms hybridized smear layer with self-etch adhesives, can prevent monomer infiltration and interfere with the chemical interaction of adhesive monomers and the underlying Dentin. The hybridized smear layer weakens the physical and chemical properties of the resin-Dentin hybridized complex both immediately and over time. Smear layer-deproteinization with NaOCl and HOCl solutions can improve the quality of resin-Dentin interface of self-etch adhesives through elimination of the hybridized smear layer, development of monomer infiltration, and enhancement of the chemical interaction of adhesive monomers with hydroxyapatite due to an increase in the mineral/organic ratio on the Dentin Surface. These positive effects are influenced by the types of oxidizing solution and their application time and also depend upon the adhesive materials used because compromising effects of residual oxidized-byproducts at the Dentin Surface on the polymerization behavior of the adhesives are different between the materials. However, applying antioxidant/reducing agents can eliminate this problem. Smear layer-deproteinization is more effective for improving the bonding efficacy of self-etch adhesives to caries-affected Dentin than normal Dentin because caries-affected Dentin produces a thicker organic-rich smear layer. Smear layer-deproteinization with HOCl solution, which has a rapid and broad-spectrum antimicrobial activity with less irritating and sensitizing properties, along with the subsequent application of antioxidant/reducing agents could enhance the longevity of composite restoration with self-etch adhesives.
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smear layer deproteinizing improves bonding of one step self etch adhesives to Dentin
Dental Materials, 2017Co-Authors: Ornnicha Thanatvarakorn, Taweesak Prasansuttiporn, Richard M Foxton, Junji Tagami, Shizuko Ichinose, Suppason Thittaweerat, Keiichi Hosaka, Masatoshi NakajimaAbstract:Abstract Objectives Smear layer deproteinizing was proved to reduce the organic phase of smear layer covered on Dentin Surface. It was shown to eliminate hybridized smear layer and nanoleakage expression in resin–Dentin bonding interface of two-step self-etch adhesive. This study aimed to investigate those effects on various one-step self-etch adhesives. Methods Four different one-step self-etch adhesives were used in this study; SE One (SE), Scotchbond™ Universal (SU), BeautiBond Multi (BB), and Bond Force (BF). Flat human Dentin Surfaces with standardized smear layer were prepared. Smear layer deproteinizing was carried out by the application of 50 ppm hypochlorous acid (HOCl) on Dentin Surface for 15 s followed by Accel® (p-toluenesulfinic acid salt) for 5 s prior to adhesive application. No Surface pretreatment was used as control. Microtensile bond strength (μTBS) and nanoleakage under TEM observation were investigated. The data were analyzed by two-way ANOVA and Tukey’s post-hoc test and t-test at the significant level of 0.05. Results Smear layer deproteinizing significantly improved μTBS of SE, SU, and BB (p Significance Smear layer deproteinizing by HOCl and Accel® application could enhance the quality of Dentin for bonding to one-step self-etch adhesives, resulting in the improving μTBS, eliminating hybridized smear layer and preventing reticular nanoleakage formation in resin–Dentin bonding interface.
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effect of a calcium phosphate based desensitizer on Dentin Surface characteristics
Dental Materials Journal, 2013Co-Authors: Ornnicha Thanatvarakorn, Taweesak Prasansuttiporn, Syozi Nakashima, Alireza Sadr, Suppason Thitthaweerat, Junji TagamiAbstract: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.
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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
Dental Materials, 2013Co-Authors: Horieh Moosavi, Suppason Thitthaweerat, Alireza Sadr, Ilnaz Hariri, Junji TagamiAbstract:Abstract 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 100 mN load with 30 s 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 17.6–22.6 MPa ( p > 0.05); however, the lowest characteristic strength was found in moist chemically cured group. Hardness ranged 437–512 MPa, 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.
J. D. Witt - One of the best experts on this subject based on the ideXlab platform.
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chemical characterization of the Dentin adhesive interface by fourier transform infrared photoacoustic spectroscopy
Dental Materials, 1992Co-Authors: Paulette Spencer, Thomas J Byerley, J. David Eick, J. D. WittAbstract:Abstract Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the Dentin Surface. The purpose of this in vitro investigation was to characterize the chemical nature of the Surface interaction between Dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crown of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6mm × 2 mm, were prepared from these sectioned teeth. The exposed Dentin Surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm −1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the Dentin Surface was collected. This Surface was primed according to manufacture's instructions and spectra recorded of the primed Surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to Surface interactions between the adhesive and the Dentin. Although early results do not indicate covalent bonding between the Dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the Dentin/adhesive interface.
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chemical characterization of the Dentin adhesive interface by fourier transform infrared photoacoustic spectroscopy
Dental Materials, 1992Co-Authors: Paulette Spencer, Thomas J Byerley, J.d. Eick, J. D. WittAbstract:Abstract Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the Dentin Surface. The purpose of this in vitro investigation was to characterize the chemical nature of the Surface interaction between Dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crown of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6mm × 2 mm, were prepared from these sectioned teeth. The exposed Dentin Surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm −1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the Dentin Surface was collected. This Surface was primed according to manufacture's instructions and spectra recorded of the primed Surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to Surface interactions between the adhesive and the Dentin. Although early results do not indicate covalent bonding between the Dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the Dentin/adhesive interface.
Paulette Spencer - One of the best experts on this subject based on the ideXlab platform.
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scanning transmission electron microscopy energy dispersive spectroscopy analysis of the Dentin adhesive interface using a labeled 2 hydroxyethylmethacrylate analogue
Journal of Dental Research, 1995Co-Authors: J.d. Eick, Thomas J Byerley, Paulette Spencer, S.j. Robinson, R P Chappell, Cecil C. ChappelowAbstract:In an attempt to compare the morphology of the Dentin adhesive interface and the wetting and penetration of the adhesive in relation to the Dentin Surface, we studied four Dentin adhesive systems using scanning transmission electron microscopy (STEM) and energy-dispersive spectroscopy (EDS). 2-Hydroxyethylmethacrylate (HEMA), a monomer common to many commercial Dentin adhesive systems, was altered to produce a thiolated analogue (HETMA). Sulfur, traceable by EDS and STEM, was substituted for the oxygen atom in the backbone of the HEMA molecule. The resulting analogue, with solubility parameters and other wetting and physical properties very similar to those of HEMA, was applied to four sets of tooth specimens, each pre-treated with a different primer or etchant. Three separate pre-treatments-nitric acid, maleic acid, and citric acid/ferric chloride—created a demineralized zone approximately 1 to 3 μm thick at the Dentin Surface. The HETMA was found to permeate freely into this zone when either of the latt...
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Dentinal tubule anastomosis a potential factor in adhesive bonding
Journal of Prosthetic Dentistry, 1994Co-Authors: R P Chappell, Paulette Spencer, Charles M Cobb, David J EickAbstract:This study investigated adhesive tag formation within Dentinal tubules and the anastomosing of lateral canals observable with scanning electron microscopy. This mechanism of micromechanical bonding had not been studied previously. The following brands of adhesives were applied to the prepared Dentin Surface of unerupted human third molars: Scotchbond Multipurpose, C&B Metabond, All-Bond 2, both etched and unetched, Tenure Solution, and XR-Bond. The experimental specimens were decalcified and prepared for SEM examination. Many tubule resin tags with lateral branching were observed. The resin branches were the result of primer, adhesive, or both entering lateral canals and communicating with adjacent tubules. The polymerization of adhesive in lateral canals was more prevalent with Scotchbond Multipurpose, C & B Metabond, and etched All-Bond 2 adhesives. The network of interconnected adhesive tags formed with these materials may be fundamental to the development of a stronger Dentin/resin bond.
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chemical characterization of the Dentin adhesive interface by fourier transform infrared photoacoustic spectroscopy
Dental Materials, 1992Co-Authors: Paulette Spencer, Thomas J Byerley, J. David Eick, J. D. WittAbstract:Abstract Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the Dentin Surface. The purpose of this in vitro investigation was to characterize the chemical nature of the Surface interaction between Dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crown of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6mm × 2 mm, were prepared from these sectioned teeth. The exposed Dentin Surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm −1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the Dentin Surface was collected. This Surface was primed according to manufacture's instructions and spectra recorded of the primed Surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to Surface interactions between the adhesive and the Dentin. Although early results do not indicate covalent bonding between the Dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the Dentin/adhesive interface.
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chemical characterization of the Dentin adhesive interface by fourier transform infrared photoacoustic spectroscopy
Dental Materials, 1992Co-Authors: Paulette Spencer, Thomas J Byerley, J.d. Eick, J. D. WittAbstract:Abstract Irreversible bonding of composite materials to tooth structure depends on chemical as well as mechanical adhesion. The proposed bonding mechanism for several commercial dental adhesives is chemical adhesion to the Dentin Surface. The purpose of this in vitro investigation was to characterize the chemical nature of the Surface interaction between Dentin and two commercial adhesives by use of Fourier transform infrared photoacoustic spectroscopy (FTIR/PAS). The occlusal thirds of the crown of freshly extracted, non-carious, unerupted human molars were sectioned perpendicular to the long axis. Dentin disks, 6mm × 2 mm, were prepared from these sectioned teeth. The exposed Dentin Surface was treated with either Scotchbond 2, a BIS-GMA resin, or Dentin-Adhesit, a polyurethane resin. All spectra were recorded from 4000 to 400 cm −1 by use of an Analect RFX-65 FTIR spectrometer equipped with an MTEC Photoacoustics Model 200 photoacoustic cell. An initial spectrum of the Dentin Surface was collected. This Surface was primed according to manufacture's instructions and spectra recorded of the primed Surface plus one to three layers of adhesive. By comparison of these spectra, it was possible for us to record changes in the phosphate and amide I and II bands due to Surface interactions between the adhesive and the Dentin. Although early results do not indicate covalent bonding between the Dentin and these adhesives, this technique presents several advantages for spectroscopic evaluation of the Dentin/adhesive interface.
Kenichi Kuroda - One of the best experts on this subject based on the ideXlab platform.
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catechol functionalized synthetic polymer as a dental adhesive to contaminated Dentin Surface for a composite restoration
Biomacromolecules, 2015Co-Authors: Carlos Gonzalezcabezas, Kenichi KurodaAbstract:This study reports a synthetic polymer functionalized with catechol groups as dental adhesives. We hypothesize that a catechol-functionalized polymer functions as a dental adhesive for wet Dentin Surfaces, potentially eliminating the complications associated with saliva contamination. We prepared a random copolymer containing catechol and methoxyethyl groups in the side chains. The mechanical and adhesive properties of the polymer to Dentin Surface in the presence of water and salivary components were determined. It was found that the new polymer combined with an Fe3+ additive improved bond strength of a commercial dental adhesive to artificial saliva contaminated Dentin Surface as compared to a control sample without the polymer. Histological analysis of the bonding structures showed no leakage pattern, probably due to the formation of Fe–catechol complexes, which reinforce the bonding structures. Cytotoxicity test showed that the polymers did not inhibit human gingival fibroblast cells proliferation. Re...
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catechol functionalized synthetic polymer as a dental adhesive to contaminated Dentin Surface for a composite restoration
Biomacromolecules, 2015Co-Authors: Sangbae Lee, Carlos Gonzalezcabezas, Kwangmahn Kim, Kyoungnam Kim, Kenichi KurodaAbstract:This study reports a synthetic polymer functionalized with catechol groups as dental adhesives. We hypothesize that a catechol-functionalized polymer functions as a dental adhesive for wet Dentin Surfaces, potentially eliminating the complications associated with saliva contamination. We prepared a random copolymer containing catechol and methoxyethyl groups in the side chains. The mechanical and adhesive properties of the polymer to Dentin Surface in the presence of water and salivary components were determined. It was found that the new polymer combined with an Fe(3+) additive improved bond strength of a commercial dental adhesive to artificial saliva contaminated Dentin Surface as compared to a control sample without the polymer. Histological analysis of the bonding structures showed no leakage pattern, probably due to the formation of Fe-catechol complexes, which reinforce the bonding structures. Cytotoxicity test showed that the polymers did not inhibit human gingival fibroblast cells proliferation. Results from this study suggest a potential to reduce failure of dental restorations due to saliva contamination using catechol-functionalized polymers as dental adhesives.
Masatoshi Nakajima - One of the best experts on this subject based on the ideXlab platform.
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smear layer deproteinization improving the adhesion of self etch adhesive systems to caries affected Dentin
Current Oral Health Reports, 2018Co-Authors: Keiichi Hosaka, Taweesak Prasansuttiporn, Ornnicha Thanatvarakorn, Richard M Foxton, Junji Tagami, Sitthikorn Kunawarote, Masahiro Takahashi, Masatoshi NakajimaAbstract:This paper reviews a new method of Dentin Surface modification, smear layer-deproteinization for self-etch adhesive systems, particularly in relation to improving the adhesion to caries-affected Dentin. Remnants of smear debris, which forms hybridized smear layer with self-etch adhesives, can prevent monomer infiltration and interfere with the chemical interaction of adhesive monomers and the underlying Dentin. The hybridized smear layer weakens the physical and chemical properties of the resin-Dentin hybridized complex both immediately and over time. Smear layer-deproteinization with NaOCl and HOCl solutions can improve the quality of resin-Dentin interface of self-etch adhesives through elimination of the hybridized smear layer, development of monomer infiltration, and enhancement of the chemical interaction of adhesive monomers with hydroxyapatite due to an increase in the mineral/organic ratio on the Dentin Surface. These positive effects are influenced by the types of oxidizing solution and their application time and also depend upon the adhesive materials used because compromising effects of residual oxidized-byproducts at the Dentin Surface on the polymerization behavior of the adhesives are different between the materials. However, applying antioxidant/reducing agents can eliminate this problem. Smear layer-deproteinization is more effective for improving the bonding efficacy of self-etch adhesives to caries-affected Dentin than normal Dentin because caries-affected Dentin produces a thicker organic-rich smear layer. Smear layer-deproteinization with HOCl solution, which has a rapid and broad-spectrum antimicrobial activity with less irritating and sensitizing properties, along with the subsequent application of antioxidant/reducing agents could enhance the longevity of composite restoration with self-etch adhesives.
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smear layer deproteinizing improves bonding of one step self etch adhesives to Dentin
Dental Materials, 2017Co-Authors: Ornnicha Thanatvarakorn, Taweesak Prasansuttiporn, Richard M Foxton, Junji Tagami, Shizuko Ichinose, Suppason Thittaweerat, Keiichi Hosaka, Masatoshi NakajimaAbstract:Abstract Objectives Smear layer deproteinizing was proved to reduce the organic phase of smear layer covered on Dentin Surface. It was shown to eliminate hybridized smear layer and nanoleakage expression in resin–Dentin bonding interface of two-step self-etch adhesive. This study aimed to investigate those effects on various one-step self-etch adhesives. Methods Four different one-step self-etch adhesives were used in this study; SE One (SE), Scotchbond™ Universal (SU), BeautiBond Multi (BB), and Bond Force (BF). Flat human Dentin Surfaces with standardized smear layer were prepared. Smear layer deproteinizing was carried out by the application of 50 ppm hypochlorous acid (HOCl) on Dentin Surface for 15 s followed by Accel® (p-toluenesulfinic acid salt) for 5 s prior to adhesive application. No Surface pretreatment was used as control. Microtensile bond strength (μTBS) and nanoleakage under TEM observation were investigated. The data were analyzed by two-way ANOVA and Tukey’s post-hoc test and t-test at the significant level of 0.05. Results Smear layer deproteinizing significantly improved μTBS of SE, SU, and BB (p Significance Smear layer deproteinizing by HOCl and Accel® application could enhance the quality of Dentin for bonding to one-step self-etch adhesives, resulting in the improving μTBS, eliminating hybridized smear layer and preventing reticular nanoleakage formation in resin–Dentin bonding interface.
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effect of Dentin pretreatment with mild acidic hocl solution on microtensile bond strength and Surface ph
Journal of Dentistry, 2010Co-Authors: Sitthikorn Kunawarote, Masatoshi Nakajima, Richard M Foxton, Kanako Shida, Yuichi Kitasako, Junji TagamiAbstract:Abstract Objectives To evaluate the pretreatment effect of mild acidic HOCl solution on the microtensile bond strength (μTBS) of a two-step self-etch adhesive to Dentin and the alteration of Dentin Surface pH. Methods Thirty-nine flat ground coronal Dentin specimens were divided into one control group and 12 experimental groups, which were treated with 6% NaOCl or 50, 100 and 200 ppm HOCl (Comfosy ® ) solutions for 5, 15 and 30 s. After rinsing with running water for 30 s, all the Dentin Surfaces were bonded with Clearfil SE Bond according to the manufacturer's instructions. After 24 h water storage, the bonded specimens were sectioned and trimmed to an hourglass shape with a cross-sectional area of approximately 1.0 mm 2 and then subjected to the μTBS test. Thirty-six mid-coronal Dentin discs were used for Surface pH measurement. Dentin Surface pH with or without pretreatment was examined using a pH-imaging microscope (SCHEM-100). The μTBS data were analyzed by one-way ANOVA (Dunnett's T3) and the Surface pH data were analyzed by non-parametric statistics (Mann–Whitney U -test). Results Pretreatment with Comfosy ® at concentrations of 50, 100 and 200 ppm did not significantly affect μTBS regardless of the application time compared with the control group, however the 100 and 200 ppm Comfosy ® groups showed significantly lower Surface pH values. For the NaOCl pretreatment groups, a longer application time significantly decreased the μTBS and increased the Surface pH values compared to the control group. Conclusions The 50 ppm Comfosy ® pretreatments for 5, 15 and 30 s did not affect the μTBS of the two-step self-etch adhesive to Dentin and Dentin Surface pH.
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Surface ph and bond strength of a self etching primer adhesive system to intracoronal Dentin after application of hydrogen peroxide bleach with sodium perborate
Operative Dentistry, 2003Co-Authors: Hanadi Elkhatib, Masatoshi Nakajima, Junji Tagami, Noriko Hiraishi, Yuichi Kitasako, Satoshi NomuraAbstract:This study compared the Dentin bond strength of a self-etching primer/adhesive system with Dentin Surface pH with or without bleaching and observed the morphological changes in bleached Dentin treated with a self-etching primer. Dentin disks were prepared from the coronal-labial region of 32 human anterior teeth. The pulpal Surfaces of the Dentin disks were polished with 600-grit SiC paper under running water. The Dentin Surfaces on all specimens were bleached with a mixture of 30% hydrogen peroxide and sodium perborate in 100% humidity at 37 degrees C for one week. The bleaching agent was then rinsed off with water for 5, 15 or 30 seconds. All specimens were stored in water at 37 degrees C. Half of the five-second rinsing specimens were stored in water for an additional week. Dentin Surface pH with or without bleaching was examined using a pH-imaging microscope (SCHEM-100). A self-etching primer/adhesive system (Clearfil SE Bond) was applied to bleached or unbleached Dentin according to the manufacturer's instructions. After 24-hour water storage, the bonded specimens were prepared for microtensile testing. Microtensile bond strength (microTBS) to Dentin was measured using a universal-testing machine (EZ test, Shimadzu, Japan) at a crosshead speed of 1.0 mm/minute. Data were analyzed by one-way ANOVA and Scheffe's test (alpha=0.05). The pH values of the Dentin Surfaces of the 5 and 15 second rinsing groups were significantly higher than the control group (p<0.05), while the 30-second rinsing and one-week water storage groups had similar Surface pH values to the control group (p<0.05). The microTBS of 5, 15 and 30 second rinsing specimens after bleaching were significantly lower than the control specimens (p<0.05). However, after one-week of water storage, the microTBS returned to the control group. The application of a bleaching agent increased the pH value of the Dentin Surface and decreased the bond strength of the self-etching primer/adhesive system. One-week water storage after bleaching recovered the Surface pH and the microTBS to Dentin.
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relationship between adhesive thickness and microtensile bond strength
Operative Dentistry, 2001Co-Authors: L Zheng, Masatoshi Nakajima, Hidehiko Sano, Patricia N R Pereira, Junji TagamiAbstract:Abstract This study evaluated the effect of the thickness of the adhesive resin layer of two commercially available resin bonding systems on bond strengths (Single Bond and Liner Bond 2V). The adhesive of Single Bond contains ethanol and water as solvents and is applied using the moist-bonding technique. The adhesive of Liner Bond 2V contains no solvents and is applied after a self-etching primer treatment. Forty-six caries-free molars were ground flat to expose the Dentin Surface and polished with #800-grit silicon carbide paper under running water. A vinyl tape punched with a 6 mm diameter hole was then placed on the Dentin Surface to demarcate the area for bonding. The thickness of the adhesive resin layer was varied by stacking an increasing numbers of vinyl tapes together. The teeth were randomly divided into two groups and treated with either Clearfil Liner Bond 2V or Single Bond. They were further divided into subgroups according to the number of tapes placed on the Dentin Surface. After the bonding procedures the teeth were incrementally restored with Clearfil AP-X resin composite, building a 5 mm high crown to produce sufficient bulk for the microtensile bond test and stored in tap water at 37 degrees C for 24 hours. The teeth were then sectioned along their long axis into 0.7 mm thick slabs and trimmed for the microtensile bond test using a super-fine diamond bur. The thickness of the adhesive resin layer was then measured with a light microscope and the slabs tested in tension at a crosshead speed of 1 mm/minute. The results were subjected to statistical analysis by a one-way analysis of variance and linear regressions with 95% confidence intervals. The thickness of the Clearfil Liner Bond 2V adhesive layer ranged from 5 mm-1500 mm, and for Single Bond, it varied from < 7.5 mm-430 mm. For Clearfil Liner Bond 2V, bond strengths increased significantly as the thickness of bonding layer increased (p < 0.05). However, the bond strengths of the Single Bond decreased significantly with increased thickness of the bonding layer (p < 0.05).