Influence of different post design and composition on stress distribution in maxillary central incisor: Finite element analysis.
BACKGROUND
Post design and material has very important effects on dentinal stress distribution since the post placement can create stresses that lead to root fracture.


METHODS
In this study we use finite element analysis (FEA) to evaluate stress distribution on endodontically treated maxillary central incisors that have been restored with different prefabricated posts. Six models were generated from the image of anatomical plate: Four metallic posts (ParaPost XH, ParaPost XT, ParaPost XP, and Flexi-Flange) and one fiberglass post (ParaPost Fiber Lux). The sixth model was a control-a sound maxillary central incisor. We used CAD software and exported the models to ANSYS 9.0. All the materials and structures were considered elastic, isotropic, homogeneous, and linear except the fiberglass post which was considered orthotropic. The values for the mechanical properties were obtained by a review of the literature and the model was meshed with 8-node tetrahedral elements. A load of 2N was applied to the lingual surface at an angle of 135 degrees.


RESULTS
The stress results were recorded by shear stress and von Mises criteria; it was observed that there was no difference for stress distribution among the titanium posts in the radicular portions and into posts. There was higher stress concentration on the coronary portion with the titanium posts than with the glass fiber post. It seems that the metallic posts' external configuration does not influence the stress distribution.


CONCLUSIONS
Fiber posts show more homogeneous stress distribution than metallic posts. The post material seems to be more relevant for the stress distribution in endodontically treated teeth than the posts' external configuration.
Silva
Natércia R
NR
Department of Operative Dentistry and Dental Materials, School of Dentistry, Federal University of Uberlandia, Uberlandia, Minas Gerais, Brazil.
Castro
Carolina G
CG
Santos-Filho
Paulo C F
PC
Silva
Gisele R
GR
Campos
Roberto E
RE
Soares
Paulo Vinicins
PV
Soares
Carlos José
CJ
D000538:Aluminum Silicates / Q000737:chemistry; D001696:Biomechanical Phenomena; D003188:Composite Resins / Q000737:chemistry; D003198:Computer Simulation; D017076:Computer-Aided Design; D003442:Crowns; D003764:Dental Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D003804:Dentin / Q000503:physiopathology; D004548:Elasticity; D020342:Finite Element Analysis; D005898:Glass / Q000737:chemistry; D006801:Humans; D007180:Incisor / Q000503:physiopathology*; D008422:Materials Testing; D008437:Maxilla / Q000503:physiopathology*; D008954:Models, Biological; D011176:Post and Core Technique / Q000295:instrumentation*; D017680:Potassium Compounds / Q000737:chemistry; D012984:Software; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry; D014092:Tooth Root / Q000503:physiopathology; D019553:Tooth, Nonvital / Q000503:physiopathology
D000538:Aluminum Silicates; D003188:Composite Resins; D003764:Dental Materials; C444701:Filtek Z250; D017680:Potassium Compounds; C009753:fiberglass; D003776:Dental Porcelain; C016447:feldspar; D014025:Titanium