Effects of cement thickness on the stress distribution of full-ceramic-endocrown restoration:A finite element analysis

doi:10.15956/j.cnki.chin.j.conserv.dent.2017.01.004

Abstract：AIM:To evaluate the effects of cement thickness on the full-ceramic-endocrown restoration using a finite element analysis model.METHODS:A finite element analysis model of mandible first molar was established using the scanning data acquired by Micro-CT.The misio-occlusio-distal cavity and endocrown restorations were simulated.The models were lined with Fuji Ⅸ glass ionomer cement.Based on cement thickness of 0,1,2 and 5 mm.A static axial and 45° loading 280 N and 105 N were respectively applied to each model.RESULTS:Compared with 0 mm group,when the glass ionomer was under 1 mm/axial condition,equivalent stress of pulp chamber floor decreased by 13.8％ (under 1 mm/45° decreased by 26.8％),shear stress of bonding layer decreased by 1.1％ (under 1 mm/45° increased by 1.4％) and equivalent stress of the distal surface of the remaining tooth decreased by 3.0％ (under 1 mm/45° increased 1.3％).Under 2 mm/axial condition equivalent stress of pulp chamber floor decreased by 31.1％ (under 2 mm/45 ° decreased by 41％),shear stress of the bonding layer increased by 3.7 ％ (under 2 mm 45° increased by 33.2％) and equivalent stress of the distal surface of the remaining tooth decreased by 0.6％ (under 2 mm/45° increased by 1.6％).For the 5 mm/axial group,equivalent stress of pulp chamber floor decreased by 37％ (under 5 mm/45° decreased by 49.1％),shear stress sof the bonding layer increased by 13％ (under 5 mm/ 45° increased by 47.2％) and equivalent stress of the distal surface of the remaining tooth decreased by 7.3％ (under 5 mm/45° increased by 10.5％).CONCLUSION:When endocrown is used for the restoration of endodontically-treated molar,a thinner cement thickness has a better effect for the long term stabilization of abutment and the endocrown.