ABSTRACT
Objective To analyze the stress distribution of the weakened root dentine restored with titanium post-core crown and fiber post-core crown by finite element method.Methods The sample was scanned by Inveon Micro-CT technology from incised margin to root apex at 21 μm interval to obtain transverse data of DICOM format.The three-dimensional finite element model was created by rebuilding the morphology of maxillary central incisor with Inveon Research Workplace as well as Mimics,Geomagic and Catia software.The model was meshed and loaded to analyze the stress distribution on the weakened dentine of root by finite element method.Results The maximum stress,shearing stress and equivalent stress of the root restored with fiber post-core crown were 60%less than the stresses of the root restored with titanium post-core crown in the experiment.The stress on various parts of the root restored with titanium post-core crown was higher than that of the root restored with fiber post-core crown.Furthermore,the stress concentration occurred mainly on the labial interface of the upper 1/3 of root. Especially when the root was restored with titanium post-core crown,the stress value reached 37 .73 MPa,which was 1.9 times that of fiber post-core crown.Conclusion The finite element analysis indicates that the fiber post-core crown is better than titanium post-core crown in avoiding stress concentration and root fracture in the restoration of weakened root of maxillary central incisors.
ABSTRACT
@#Among the variety of post and core materials, fiber post is getting more and more popular because of its excellent physical and mechanical characters, superior aesthetics properties. However, it also has some limitations. In the restoration of damaged teeth, there should be more dentin ferrule, and the different designs of ferrule affect the retention, stability and root fracture resistance of teeth restored with fiber posts. The purpose of this article is to give a literature review of the effect of ferrule on teeth restored with fiber posts.
ABSTRACT
Objective To investigate the influence of different kinds of post?core materials on fracture resistant ability of different walls during weakened root restoration. Methods Forty?eight human single root mandibular first premolars were randomly assigned to two groups(groupⅠwas repaired with quartz?fiber post?core and mental crown ,and groupⅡwas repaired with Co?Cr cast metal post?core and mental crown). Each main group was then divided into four subgroups of 6 specimens. All samples were tested on the universal test machine. We observed the fracture load and the fracture mode of the specimens. Results Cr?Co ally post?core group exhibited significantly higher resistance to fracture than quartz fiber post?core in the same number weakened root walls(P<0.05). With the increase in the quantity of weakened root walls ,the fracture resistance was significant decreased in the same post?core material(P<0.05). The possibility of repairable fractures in groupⅠwas significantly higher than that in groupⅡ(P<0.05). Conclusion Cr?Co alloy post?core can bear a higher bite ,but quartz fiber post?core has the most favorable fracture modes.