The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Noriyuki Wakabayashi - One of the best experts on this subject based on the ideXlab platform.
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stress distribution in root filled teeth restored with various Post and Core techniques effect of Post length and crown height
International Endodontic Journal, 2015Co-Authors: Kimisuke Kainose, Noriyuki Wakabayashi, M Nakajima, Richard M Foxton, Junji TagamiAbstract:Abstract Kainose K, Nakajima M, Foxton R, Wakabayashi N,Tagami J. Stress distribution in root filled teeth restoredwith various Post and Core techniques: effect of Post lengthand crown height. International Endodontic Journal. Aim To investigate interfacial stress distribution inrestored root filled teeth with various Post lengthsand crown heights.Methodology Three-dimensional mathematicalmodels of a root filled mandibular premolar toothwere constructed. Parts of the tooth structures werereplaced with ceramic crowns having three crownheights incorporating, either a cast Post and Core or aresin Post and Cores with fibre Post or metallic Postwith four Post lengths. Finite element linear analysiswas performed to calculate equivalent and shearstress distribution at the interfaces between the teethand Post and Cores under mesiodistal symmetricalboundary conditions and an oblique static load of400 N.Results For the resin Post and Core with fibre andmetallic Posts, shear stress at the interface was greaterin the cervical area than the Post area, depending onthe crown height. The resin Post and Core with metallicPost had lower shear stress at the interface of cervicalarea than that of the fibre Post model; however, themetallic Post models produced a high concentration ofshear stress at the interface between the Post and resincomposite. On the other hand, for the cast Post andCore, the shear stress at the interface was mainly pro-duced in the Post end area, which increased withdecrease of Post length.Conclusions For the resin Post and Core, bondingintegrity to the cervical area would play a critical rolein the survival of the restored tooth, whereas for thecast Post and Core, the bond of the Post would beessential.Keywords: adhesive, debonding, finite elementanalysis, fracture, root, stress.
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the influence of elastic modulus mismatch between tooth and Post and Core restorations on root fracture
International Endodontic Journal, 2013Co-Authors: Noriyuki Wakabayashi, T Yamazaki, Atsushi Takaichi, Yoshimasa IgarashiAbstract:Ona M, Wakabayashi N, Yamazaki T, Takaichi A, Igarashi Y. The influence of elastic modulus mismatch between tooth and Post and Core restorations on root fracture. International Endodontic Journal. Aim To investigate the influence of elastic modulus mismatch between tooth and Post and Core restorations on mechanisms of root fracture. Methodology Three-dimensional mathematical models of a root filled maxillary premolar tooth with supporting periodontium were constructed. The tooth was restored with a cast Ni–Cr alloy or fibre-reinforced composite Post and Core that was bonded or nonbonded to dentine. In the nonbonded simulation, a nonlinear contact analysis was executed to simulate a friction and a potential sliding phenomenon in the interface between tooth and Post and Core. Risks of root fracture and debonding at the bonded interface were estimated based on the principal stress of the root and the shear stress on the interface, respectively. Results The fracture risk of the bonded cast Post and Core was lower than that of the composite Post and Core, although the cast restoration exhibited eight times greater stress than the composite. The risk of root fracture based on the tensile stress of the tooth structures was higher with the bonded composite Post and Core than that with the cast Post and Core. These stresses doubled when the restorations were not bonded to the tooth structures. The risk of debonding of the cast Post and Core based on the shear stress was approximately twice that of the composite Post and Core. Conclusions The elastic modulus mismatch appears to be a factor responsible for the debonding of Post and Cores from root canals, with the potential to increase the risk of root fracture indirectly.
G A Freedman - One of the best experts on this subject based on the ideXlab platform.
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esthetic Post and Core treatment
Dental Clinics of North America, 2001Co-Authors: G A FreedmanAbstract:: The dilemma that confronts the practitioner in the area of Post-endodontic rehabilitation is a positive one. The variety of products and techniques available offer practical solutions to most restorative problems. Patients have benefited [figure: see text] from recent developments in Post-and-Core technology, and continue to reap the benefits of research and development. The ideal system of products for the endodontic-restorative continuum includes: an esthetic resin fiber Post a composite Core an automixed resin luting cement current techniques that combine the automixed resin luting cement and composite Core into the same component.
Junji Tagami - One of the best experts on this subject based on the ideXlab platform.
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stress distribution in root filled teeth restored with various Post and Core techniques effect of Post length and crown height
International Endodontic Journal, 2015Co-Authors: Kimisuke Kainose, Noriyuki Wakabayashi, M Nakajima, Richard M Foxton, Junji TagamiAbstract:Abstract Kainose K, Nakajima M, Foxton R, Wakabayashi N,Tagami J. Stress distribution in root filled teeth restoredwith various Post and Core techniques: effect of Post lengthand crown height. International Endodontic Journal. Aim To investigate interfacial stress distribution inrestored root filled teeth with various Post lengthsand crown heights.Methodology Three-dimensional mathematicalmodels of a root filled mandibular premolar toothwere constructed. Parts of the tooth structures werereplaced with ceramic crowns having three crownheights incorporating, either a cast Post and Core or aresin Post and Cores with fibre Post or metallic Postwith four Post lengths. Finite element linear analysiswas performed to calculate equivalent and shearstress distribution at the interfaces between the teethand Post and Cores under mesiodistal symmetricalboundary conditions and an oblique static load of400 N.Results For the resin Post and Core with fibre andmetallic Posts, shear stress at the interface was greaterin the cervical area than the Post area, depending onthe crown height. The resin Post and Core with metallicPost had lower shear stress at the interface of cervicalarea than that of the fibre Post model; however, themetallic Post models produced a high concentration ofshear stress at the interface between the Post and resincomposite. On the other hand, for the cast Post andCore, the shear stress at the interface was mainly pro-duced in the Post end area, which increased withdecrease of Post length.Conclusions For the resin Post and Core, bondingintegrity to the cervical area would play a critical rolein the survival of the restored tooth, whereas for thecast Post and Core, the bond of the Post would beessential.Keywords: adhesive, debonding, finite elementanalysis, fracture, root, stress.
Jeffrey W Hutter - One of the best experts on this subject based on the ideXlab platform.
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survival rate and fracture strength of incisors restored with different Post and Core systems and endodontically treated incisors without coronoradicular reinforcement
Journal of Endodontics, 2002Co-Authors: Oliver Pontius, Jeffrey W HutterAbstract:This in vitro study evaluated the survival rate and fracture resistance of maxillary central incisors restored with different Post and Core systems. The Post and Core systems investigated were a prefabricated high precious metal Post with cast Core (group A), zirconia Post with a prefabricated bonded ceramic Core (group B), and a resin-ceramic interpenetrating phase composite Post (experimental) with a prefabricated bonded ceramic Core (group C). The all-ceramic copings were cemented using Panavia 21 TC. In the group without coronoradicular reinforcement, the access cavity was closed with a light-cured composite in combination with a dentine-bonding agent (group D). Each specimen was intermittently loaded and thermocycled before final stress tests in a Zwick machine. The survival rates after 1,200,000 cycles in the artificial mouth were 90% (group A), 80% (group B), 60% (group C), and 100% (group D). Statistically significant differences were found between all groups with the exception of A and B, when failure during cyclic loading was included (Kruskal-Wallis multiple comparisons test). Samples restored with a cast Post and Core demonstrated more vertical root fractures. It was concluded that the preservation of both internal and external tooth structure is of utmost importance when restoring endodontically treated teeth.
Yoshimasa Igarashi - One of the best experts on this subject based on the ideXlab platform.
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the influence of elastic modulus mismatch between tooth and Post and Core restorations on root fracture
International Endodontic Journal, 2013Co-Authors: Noriyuki Wakabayashi, T Yamazaki, Atsushi Takaichi, Yoshimasa IgarashiAbstract:Ona M, Wakabayashi N, Yamazaki T, Takaichi A, Igarashi Y. The influence of elastic modulus mismatch between tooth and Post and Core restorations on root fracture. International Endodontic Journal. Aim To investigate the influence of elastic modulus mismatch between tooth and Post and Core restorations on mechanisms of root fracture. Methodology Three-dimensional mathematical models of a root filled maxillary premolar tooth with supporting periodontium were constructed. The tooth was restored with a cast Ni–Cr alloy or fibre-reinforced composite Post and Core that was bonded or nonbonded to dentine. In the nonbonded simulation, a nonlinear contact analysis was executed to simulate a friction and a potential sliding phenomenon in the interface between tooth and Post and Core. Risks of root fracture and debonding at the bonded interface were estimated based on the principal stress of the root and the shear stress on the interface, respectively. Results The fracture risk of the bonded cast Post and Core was lower than that of the composite Post and Core, although the cast restoration exhibited eight times greater stress than the composite. The risk of root fracture based on the tensile stress of the tooth structures was higher with the bonded composite Post and Core than that with the cast Post and Core. These stresses doubled when the restorations were not bonded to the tooth structures. The risk of debonding of the cast Post and Core based on the shear stress was approximately twice that of the composite Post and Core. Conclusions The elastic modulus mismatch appears to be a factor responsible for the debonding of Post and Cores from root canals, with the potential to increase the risk of root fracture indirectly.