Finite elements study of the Flexi Post and Flexi Flange post systems in a maxillary central incisor.
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The use of post and core systems has become an excellent alternative for restoring endodontically treated teeth. The aim of this study was to evaluate the von Mises, maximal compressive and tensile stresses distribution using the Finite Element Method (FEM) on human teeth restored with different post and core systems. The analysis was made on endodontically treated maxillary central incisors. The post systems used in this investigation were the stainless steel or titanium Flexi Post/Flexi Flange. Composite resin was used as core material and resin cement was the cement material of choice to seat a full porcelain crown. The bi-dimensional mathematical model was created from pictures taken from an intact human maxillary central incisor and prefabricated posts. This image was transferred to a personal computer in the MSC/Nastran 4.5 software. A static and linear analysis treatment was performed when a 45 load of 100 N was applied on the lingual surface of the tooth. Based on the results obtained, it can be concluded that the post design and its material can alter the stress pattern distribution. (+info)
Mechanical versus chemical retention for restoring complex restorations: what is the evidence?
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This article reports the findings from a study conducted to answer this research question: can adhesive resin liners provide retention that is the same as dentinal pins or pots and slots when restoring complex amalgam restorations? The study methodology consisted of two components: a review of the literature and a survey to assess methods and materials that general practitioners use in their clinical practice for restoring complex amalgam restorations. Even though a vast majority of the general practitioners surveyed reported using dentinal pins or pots and slots, the occurrence or frequency of use was under 50 percent. It was also reported from the survey that over half the respondents are using adhesive resin liners exclusively when restoring complex restorations. New and improved materials allow general practitioners to restore complex restorations without the risks associated with the placement of pins or pots and slots. A review of the available literature indicates that adhesive resin liners may be used as an alternative or adjunct to mechanical retention. Because of the improvements of bonding strength of adhesive resin liners, dentinal pins and pots and slots should not be the only methods considered when faculty assist students in the development of treatment plans for patients who need complex amalgam restorations. (+info)
Biocompatibility evaluation of a new bioresorbable pin for membrane fixation.
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