Objective      To investigate the effect of different thickness of cement on residual dentine and stress statement in post and core restored maxillary central incisor.        Methods      The three dimensional finite element models of post and core restored maxillary central incisor with different thickness of cement were established by computer

with simulation of the protruding and oblique loads. The stress peak and distribution of dentine and cement of Von Mises

the maximum stress and shear stress were analyzed to investigate the effect of different thickness of cement in each model respectively.       Results      The stress distribution inside the dentine from different models was similar with the increase of thickness of cement. Under protruding load

Von Mises and the maximum stress on dentine in three models showed significant stress concentration at root apex

but for oblique load

the stresses showed significant stress concentration at the lingual cervical margin and at the cervical one third of the tooth. The peaks of Von Mises

and the maximum stress inside the dentine were indistinctively reduced

but the peaks of them and shear stress in the cement were reduced obviously. When the thickness of cement was 100 μm under protruding load

peak value of shear stress in XY and YZ direction on the cement was reduced most significantly

by 63.22% and 51.46% respectively less than when the thickness was 30 μm.       Conclusion      The thickness of cement has few effects on stress of dentine

but significant on cement itself

which suggests it can reduce the stress peak in cement when proper increasing the thickness.