Premolars restored with posts of different materials

Dental Materials Journal 2011;; 30(6): 881–886
Premolars restored with posts of different materials: fatigue analysis
Pablo-­Jesús RODRíGUEZ-­CERVANTES1, Joaquín-­Luis SANCHO-­BRU1, Carmen GONZÁLEZ-­LLUCH1, Antonio PÉREZ-­ GONZÁLEZ1, Amaya BARJAU-­ESCRIBANO2 and Leopoldo FORNER-­NAVARRO2
Department of Mechanical Engineering and Construction, University Jaume I, E-­12071, Castellón de la Plana, Spain
Department of Stomatology, University of Valencia, E-­ 46010, Valencia, Spain
Corresponding author, Pablo-­Jesús RODRíGUEZ-­CERVANTES;; E-­mail: cervante@emc.uji.es
1
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used in premolars restorations.
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INTRODUCTION
Endodontically treated teeth have less moisture in the
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brittleness1). The ability of a post and core system to
survive masticatory forces (the instantaneous loading
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critical to the survival of a restoration. If either the post
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a core is an important factor in preventing restoration
failures. Much of the literature has described techniques
and methods for the construction of posts and cores
including cast systems and prefabricated post systems.
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about allergic reactions or biocompatibility4) SDWLHQWV
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It is possible to replicate the aesthetic characteristics
and vitality of natural teeth by using ceramics5). The
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at the same time. Ceramic materials are superior in
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under tensile and torsional stresses6)7KLVGUDZEDFNKDV
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have advantages and disadvantages. In vitro tests can
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consuming and only a limited number of specimens can
be tested. The transfer of results from in vitro tests to
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results depends on construction of an appropriate model.
A meticulous construction process is therefore necessary.
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the elastic modulus of the post is similar to that of
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essential
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restorations. They reproduce cyclical loading pattern
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by means of computer simulation.
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Dent Mater J 2011;; 30(6): 881–886
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post and composite core.
MATERIALS AND METHODS $WKHRUHWLFDOPHWKRGZDVXVHGWRVWXG\WKHLQÁXHQFHRI
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and the ParaPost Stainless Steel (Coltène/Whaledent
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because their geometry is similar and they are
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White DQG*3DIRUWKHParapost Stainless Steel).
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also applicable to biological problems. The results of a
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structures under investigation. These stresses may be
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equivalent von Mises stress. Von Mises stresses depend
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of the possibility of damage occurrence.
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obtained from the literature and from the manufacturer
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aforementioned properties are presented in Table 1.
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displacements of all nodes on the lateral surface and
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constrained.
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Modelled components.
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Component/Material
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Periodontal ligament
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restored using the ParaPost Fiber White and the
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direction. An unfavourable situation of malocclusion
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buccal incline of the palatal cusp. The value of the
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biting force24)7KLVYDOXHKDVEHHQXVHGLQVHYHUDOZRUNV
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pattern provided information about the fracture
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reaching the failure load.
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depend
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recommendation that post length should be about three
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Fatigue Model from previous FEA
The behaviour of materials under dynamic loads is
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cyclical loading. The material collapses at maximum
stress values that are lesser than the ultimate tensile
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the material.
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‡6fYV‡6fYV6DQG‡6f vs. a number
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have tested 1.2 millions of cycles. Sf LV WKH ÁH[XUDO
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material.
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1.2 millions of cycles. These conditions are believed to
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This number of cycles have been used in several fatigue
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is bigger. i.e.WKHPRGHOSUHGLFWVWKDWUHVWRUDWLRQVXVLQJ
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Results from the fatigue model from previous FEA
The model predicted no fatigue failure for both post
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cyclical load considered is good enough to represent the
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RESULTS
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stress distribution achieved. We prefer the more visual
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component material and the maximal von Mises stress
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Table 2. A smaller factor of safety means that the
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the components can be considered as the factor of safety
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using stainless steel post (right).
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stainless steel post (right).
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stainless steel post (right).
Dent Mater J 2011;; 30(6): 881–886
885
DISCUSSION
CONCLUSION
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static analysis. It has to be pointed out that the results
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The magnitude and direction of the force applied are
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premolars. The analysis of the factor of safety (under
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Many studies in the literature address fatigue of a
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elastic modulus of the post is similar to that of dentine
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Although the method used is more clinically relevant
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limitations exist in the interpretation of these results
from a clinical perspective. The specimens in this model
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that may not fully represent the clinical situation.
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biomechanics of teeth restored using intraradicular
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interpret. The results are more realistic because the
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masticatory loads. The main limitation of the method is
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manufacturers.
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differences found in the static analysis.
ACKNOWLEDGMENTS
This research is supported by both the Spanish
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