The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Marco Ferrari - One of the best experts on this subject based on the ideXlab platform.
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dye leakage and sem study of roots obturated with thermafill and Dentin Bonding agent
Dental Traumatology, 1999Co-Authors: Francesco Mannocci, M Innocenti, E Bertelli, Marco FerrariAbstract:The apical seal of roots obturated with a Dentin Bonding agent and Thermafill with and without the use of sodium hypochlorite as an irrigating solution was compared by a dye leakage test. Roots obturated with Thermafill and a zinc oxide eugenol sealer were used as controls. Thirty-eight roots were prepared chemomechanically and divided into three experimental groups. The teeth of group 1 were filled with Thermafill and the Dentin Bonding agent using sodium hypochlorite as the irrigant. The teeth of group 2 were filled in the same way, but saline solution was used as the irrigant. Before the root canal was filled the smear layer was removed from the root canal walls of both groups by rinsing the root canal with a 17% EDTA solution. The teeth of group 3 were filled with Thermafill and a zinc oxide eugenol sealer. The teeth were immersed in 2% methylene blue solution. The root fillings of groups 1 and 2 leaked significantly more than those of group 3. The resin-Dentin-guttapercha interface of group 1 was observed by scanning electron microscopy and showed a typical hybrid layer. An intimate contact between resin and Dentin was present in group 2, but a resin-Dentin interdiffusion zone was only occasionally observed. The use of dental adhesives and the hybrid layer formation did not improve the seal of Thermafill root canal fillings.
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stereomicroscopic and scanning electron microscopic study of roots obturated with vertically condensed gutta percha epoxy resin cement and Dentin Bonding agent
Journal of Endodontics, 1998Co-Authors: Francesco Mannocci, Marco Innocenti, Marco FerrariAbstract:Root canal fillings performed with Dentin Bonding agent, gutta-percha, and epoxy resin sealer were observed by stereomicroscope. Fourteen palatal roots of extracted maxillary molars were used. Seven roots (group 1) were filled with gutta-percha, epoxy resin sealer, and Dentin Bonding agent. Seven (group 2) were filled with gutta-percha and epoxy resin sealer alone. The presence of these materials (gutta-percha, adhesive, cement, and a combination of these materials) and the number of voids present were evaluated in the apical, middle, and coronal thirds of the canals. In group 1, a combination of the three materials used was found to be the statistically most frequent case only in the apical third. No statistically significant difference was found between the overall number of voids present in the two groups. The resin-Dentin-gutta-percha interface of roots from group 1 was observed by scanning electron microscopy: no statistically significant difference was found between apical and coronal sections regarding the presence of hybrid layer, penetration of resin into the Dentinal tubules, or the presence of gaps in either the Dentin-resin interface or the resin-gutta-percha interface.
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apical seal of roots obturated with laterally condensed gutta percha epoxy resin cement and Dentin Bonding agent
Journal of Endodontics, 1998Co-Authors: Francesco Mannocci, Marco FerrariAbstract:The apical seal of roots obturated with either of two kinds of Dentin Bonding agent, gutta-percha and epoxy-resin-based root canal sealer, was compared by a die leakage test with that of an epoxy resin root canal sealer and gutta-percha without a Bonding agent. Thirty-two roots were prepared chemomechanically and divided into three experimental groups. Group 1 was filled with gutta-percha, epoxy-resin sealer, and All-Bond 2 Adhesive. Group 2 was filled with gutta-percha, epoxy-resin sealer, and Scotchbond Multi-Purpose Plus adhesive. Group 3 was filled with gutta-percha and epoxy resin sealer. The teeth were immersed in 2% methylene blue solution. Groups 1 and 2 leaked significantly less than group 3. The materials most frequently observed at the apex were in group 1 dental adhesive and in group 2 gutta-percha. The interface between Dentin and the adhesive materials in groups 1 and 2 was examined by scanning electron microscope and showed a hybrid-like layer.
Francesco Mannocci - One of the best experts on this subject based on the ideXlab platform.
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dye leakage and sem study of roots obturated with thermafill and Dentin Bonding agent
Dental Traumatology, 1999Co-Authors: Francesco Mannocci, M Innocenti, E Bertelli, Marco FerrariAbstract:The apical seal of roots obturated with a Dentin Bonding agent and Thermafill with and without the use of sodium hypochlorite as an irrigating solution was compared by a dye leakage test. Roots obturated with Thermafill and a zinc oxide eugenol sealer were used as controls. Thirty-eight roots were prepared chemomechanically and divided into three experimental groups. The teeth of group 1 were filled with Thermafill and the Dentin Bonding agent using sodium hypochlorite as the irrigant. The teeth of group 2 were filled in the same way, but saline solution was used as the irrigant. Before the root canal was filled the smear layer was removed from the root canal walls of both groups by rinsing the root canal with a 17% EDTA solution. The teeth of group 3 were filled with Thermafill and a zinc oxide eugenol sealer. The teeth were immersed in 2% methylene blue solution. The root fillings of groups 1 and 2 leaked significantly more than those of group 3. The resin-Dentin-guttapercha interface of group 1 was observed by scanning electron microscopy and showed a typical hybrid layer. An intimate contact between resin and Dentin was present in group 2, but a resin-Dentin interdiffusion zone was only occasionally observed. The use of dental adhesives and the hybrid layer formation did not improve the seal of Thermafill root canal fillings.
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stereomicroscopic and scanning electron microscopic study of roots obturated with vertically condensed gutta percha epoxy resin cement and Dentin Bonding agent
Journal of Endodontics, 1998Co-Authors: Francesco Mannocci, Marco Innocenti, Marco FerrariAbstract:Root canal fillings performed with Dentin Bonding agent, gutta-percha, and epoxy resin sealer were observed by stereomicroscope. Fourteen palatal roots of extracted maxillary molars were used. Seven roots (group 1) were filled with gutta-percha, epoxy resin sealer, and Dentin Bonding agent. Seven (group 2) were filled with gutta-percha and epoxy resin sealer alone. The presence of these materials (gutta-percha, adhesive, cement, and a combination of these materials) and the number of voids present were evaluated in the apical, middle, and coronal thirds of the canals. In group 1, a combination of the three materials used was found to be the statistically most frequent case only in the apical third. No statistically significant difference was found between the overall number of voids present in the two groups. The resin-Dentin-gutta-percha interface of roots from group 1 was observed by scanning electron microscopy: no statistically significant difference was found between apical and coronal sections regarding the presence of hybrid layer, penetration of resin into the Dentinal tubules, or the presence of gaps in either the Dentin-resin interface or the resin-gutta-percha interface.
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apical seal of roots obturated with laterally condensed gutta percha epoxy resin cement and Dentin Bonding agent
Journal of Endodontics, 1998Co-Authors: Francesco Mannocci, Marco FerrariAbstract:The apical seal of roots obturated with either of two kinds of Dentin Bonding agent, gutta-percha and epoxy-resin-based root canal sealer, was compared by a die leakage test with that of an epoxy resin root canal sealer and gutta-percha without a Bonding agent. Thirty-two roots were prepared chemomechanically and divided into three experimental groups. Group 1 was filled with gutta-percha, epoxy-resin sealer, and All-Bond 2 Adhesive. Group 2 was filled with gutta-percha, epoxy-resin sealer, and Scotchbond Multi-Purpose Plus adhesive. Group 3 was filled with gutta-percha and epoxy resin sealer. The teeth were immersed in 2% methylene blue solution. Groups 1 and 2 leaked significantly less than group 3. The materials most frequently observed at the apex were in group 1 dental adhesive and in group 2 gutta-percha. The interface between Dentin and the adhesive materials in groups 1 and 2 was examined by scanning electron microscope and showed a hybrid-like layer.
David H Pashley - One of the best experts on this subject based on the ideXlab platform.
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extrafibrillar collagen demineralization based chelate and rinse technique bridges the gap between wet and dry Dentin Bonding
Acta Biomaterialia, 2017Co-Authors: Lisha Gu, Fucong Tian, D Arola, Ji Hua Chen, Yang Jiao, David H PashleyAbstract:Abstract Limitations associated with wet-Bonding led to the recent development of a selective demineralization strategy in which Dentin was etched with a reduced concentration of phosphoric acid to create exclusive extrafibrillar demineralization of the collagen matrix. However, the use of acidic conditioners removes calcium via diffusion of very small hydronium ions into the intrafibrillar collagen water compartments. This defeats the purpose of limiting the conditioner to the extrafibrillar space to create a collagen matrix containing only intrafibrillar minerals to prevent collapse of the collagen matrix. The present work examined the use of polymeric chelators (the sodium salt of polyacrylic acid) of different molecular weights to selectively demineralize extrafibrillar Dentin. These polymeric chelators exhibit different affinities for calcium ions (isothermal titration calorimetry), penetrated intrafibrillar Dentin collagen to different extents based on their molecular sizes (modified size-exclusion chromatography), and preserve the dynamic mechanical properties of mineralized Dentin more favorably compared with completely demineralized phosphoric acid-etched Dentin (nanoscopical dynamic mechanical analysis). Scanning and transmission electron microscopy provided evidence for retention of intrafibrillar minerals in Dentin surfaces conditioned with polymeric chelators. Microtensile bond strengths to wet-bonded and dry-bonded Dentin conditioned with these polymeric chelators showed that the use of sodium salts of polyacrylic acid for chelating Dentin prior to Bonding did not result in significant decline in resin-Dentin bond strength. Taken together, the findings led to the conclusion that a chelate-and-rinse conditioning technique based on extrafibrillar collagen demineralization bridges the gap between wet and dry Dentin Bonding. Statement of Significance The chelate-and-rinse dental adhesive Bonding concept differentiates from previous research in that it is based on the size-exclusion characteristics of fibrillar collagen; molecules larger than 40 kDa are prevented from accessing the intrafibrillar water compartments of the collagen fibrils. Using this chelate-and-rinse extrafibrillar calcium chelation concept, collagen fibrils with retained intrafibrillar minerals will not collapse upon air-drying. This enables adhesive infiltration into the mineral-depleted extrafibrillar spaces without relying on wet-Bonding. By bridging the gap between wet and dry Dentine Bonding, the chelate-and-rinse concept introduces additional insight to the field by preventing exposure of endogenous proteases via preservation of the intrafibrillar minerals within a collagen matrix. If successfully validated, this should help prevent degradation of resin-Dentine bonds by collagenolytic enzymes.
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effect of removal of surface collagen fibrils on resin Dentin Bonding
Dental Materials, 1999Co-Authors: Carlo Prati, Stefano Chersoni, David H PashleyAbstract:Abstract Objectives: The aim of this study was to evaluate the effects of NaOCl at removing the demineralized layer by examining the morphology of the hybrid layer and measuring shear bond strengths after different Dentin treatments. Methods: Dentin disks were treated with: (1) 35% phosphoric acid (PA) 20 s; (2) PA treatment followed by 1.5% NaOCl, 2 min; (3) PA treatment, followed by a 10% NaOCl immersion for 120 h. SEM was used to analyze the morphology of Dentin and its interface with Dentin Bonding agents (DBAs), while shear bond strength tests were used to measure adhesion. All specimens were then fractured into two halves: One half was inspected under SEM; the other half was sequentially placed in 10% PA followed by 12.5% NaOCl for 70 h, to remove all Dentin from the resin replica of the original bonded interface. Results: SEM observations showed that collagen fibrils were completely removed from the acid-etched surface by NaOCl treatment. The diameter and the size of Dentinal tubules and the number of lateral branches of the tubules were increased following NaOCl treatment. NaOCl applied on Dentin smear layers did not significantly modify their SEM morphology. Resin tags were larger in diameter after phosphoric acid/NaOCl treatment than after only phosphoric acid treatment. Resin-infiltrated Dentin-layers were only observed after the single phosphoric acid (i.e. conventional etching) procedure, and were not observed after combined phosphoric acid/NaOCl treatment. Etched/NaOCl samples showed a lower bond strength using Scotchbond MP and 3M Single Bond, but were higher in Optibond FL and unmodified in Prime & Bond 2.0 groups when compared with acid-etched controls. Treatment of etched Dentin with NaOCl for 120 h produced an unusual type of resin infiltration of mineralized Dentin that could be called a “reverse hybrid layer” which may explain the mechanism of resin Bonding to NaOCl treated Dentin. Significance: The use of acidic conditioners for exposure of the collagen matrix exposes a soft delicate mesh that can collapse, thereby interfering with resin infiltration. If acid-etching is followed by NaOCl treatment, high bond strengths can be achieved via “reverse hybrid layer” formation, a proposed new mechanism of micromechanical resin retention. This mechanism is not yet recommended for clinical use but demonstrates a new type of resin retention.
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Adhesion testing of Dentin Bonding agents: A review
Dental Materials, 1995Co-Authors: David H Pashley, Hidehiko Sano, B. Ciucchi, Masahiro Yoshiyama, Ricardo M. CarvalhoAbstract:Abstract Adhesion testing of Dentin Bonding agents was reviewed starting with the adhesion substrate, Dentin, the variables involved in etching, priming and Bonding, storage variables and testing variables. Several recent reports attempting to standardize many of these variables were discussed. Recent advances in the development of new Bonding systems have resulted in bond strengths on the order of 20–30 MPa. At these high bond strengths, most of the bond failure modes have been cohesive in Dentin. As this precludes measurement of interfacial bond strength, new testing methods must be developed. One such new method, a microtensile method, was described along with preliminary results that have been obtained. The last decade has produced major advances in Dentin Bonding. The next decade should prove to be even more exciting.
K R Volkmann - One of the best experts on this subject based on the ideXlab platform.
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in vitro bacterial penetration of endodontically treated teeth coronally sealed with a Dentin Bonding agent
Journal of Endodontics, 2001Co-Authors: G A Wolanek, Robert J Loushine, R N Weller, W F Kimbrough, K R VolkmannAbstract:This study evaluated the effectiveness of a Dentin Bonding agent as a barrier to prevent coronal microleakage and examined the effect of a eugenol-based sealer on the sealing ability of this resin adhesive. Fifty-one extracted human mandibular molars were incorporated in a model system using an oral streptococci as a microbial marker. Group 1 consisted of 15 teeth that were obturated with only gutta-percha and received a coronal barrier of Clearfil Liner Bond 2V. Group 2 was identical to group 1, but included the use of a eugenol-based sealer in the obturation. Group 3 consisted of 15 teeth that were obturated with gutta-percha and sealer, but did not receive a coronal barrier. Six teeth served as controls. Bacterial penetration was monitored for 90 days. Results were analyzed after 30, 60, and 90 days with Fisher's exact test (p < 0.05). All controls behaved as expected. Neither group 1 nor group 2 exhibited any bacterial leakage. Eleven of the 15 specimens in group 3 leaked between 15 and 76 days. The coronal barriers in group 1 and group 2 were significantly better in preventing coronal microleakage at 60 days (p = 0.002) and 90 days (p = 0.00005). The presence of eugenol in the sealer had no significant effect on the sealing ability of Clearfil Liner Bond 2V (p = 1).
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clinical articles in vitro bacterial penetration of endodontically treated teeth coronally sealed with a Dentin Bonding agent
2001Co-Authors: G A Wolanek, Robert J Loushine, Norman R Weller, Frank W Kimbrough, K R VolkmannAbstract:This study evaluated the effectiveness of a Dentin Bonding agent as a barrier to prevent coronal microleakage and examined the effect of a eugenolbased sealer on the sealing ability of this resin adhesive. Fifty-one extracted human mandibular molars were incorporated in a model system using an oral streptococci as a microbial marker. Group 1 consisted of 15 teeth that were obturated with only gutta-percha and received a coronal barrier of Clearfil Liner Bond 2V. Group 2 was identical to group 1, but included the use of a eugenol-based sealer in the obturation. Group 3 consisted of 15 teeth that were obturated with gutta-percha and sealer, but did not receive a coronal barrier. Six teeth served as controls. Bacterial penetration was monitored for 90 days. Results were analyzed after 30, 60, and 90 days with Fisher’s exact test (p < 0.05). All controls behaved as expected. Neither group 1 nor group 2 exhibited any bacterial leakage. Eleven of the 15 specimens in group 3 leaked between 15 and 76 days. The coronal barriers in group 1 and group 2 were significantly better in preventing coronal microleakage at 60 days (p 5 0.002) and 90 days (p 5 0.00005). The presence of eugenol in the sealer had no significant effect on the sealing ability of Clearfil Liner Bond 2V (p 5 1).
Marco Innocenti - One of the best experts on this subject based on the ideXlab platform.
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stereomicroscopic and scanning electron microscopic study of roots obturated with vertically condensed gutta percha epoxy resin cement and Dentin Bonding agent
Journal of Endodontics, 1998Co-Authors: Francesco Mannocci, Marco Innocenti, Marco FerrariAbstract:Root canal fillings performed with Dentin Bonding agent, gutta-percha, and epoxy resin sealer were observed by stereomicroscope. Fourteen palatal roots of extracted maxillary molars were used. Seven roots (group 1) were filled with gutta-percha, epoxy resin sealer, and Dentin Bonding agent. Seven (group 2) were filled with gutta-percha and epoxy resin sealer alone. The presence of these materials (gutta-percha, adhesive, cement, and a combination of these materials) and the number of voids present were evaluated in the apical, middle, and coronal thirds of the canals. In group 1, a combination of the three materials used was found to be the statistically most frequent case only in the apical third. No statistically significant difference was found between the overall number of voids present in the two groups. The resin-Dentin-gutta-percha interface of roots from group 1 was observed by scanning electron microscopy: no statistically significant difference was found between apical and coronal sections regarding the presence of hybrid layer, penetration of resin into the Dentinal tubules, or the presence of gaps in either the Dentin-resin interface or the resin-gutta-percha interface.