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
Objective:To determine synchronously protocatechuic aldehyde and danshensu in Compound Danshen Lozenge and Dropping Pills.Methods:HPLC method was used.Results:The average recoveries(n=5) were 100.47% for Danshensu of Compound Danshensu Lozenge(RSD=1.08%) and 99.27% for protocatechuic aldehyde(RSD=1.22%), respectively. And the average recoveries(n=3) were 100.40% for Danshensu of Compound Danshen Dropping Pills(RSD=0.65%) and 98.47% for protocatechuic aldehyde(RSD=1.76%).Conclusion:This method is simple, quick with a good separation.