Three-dimensional finite element analysis of one-piece computer aided design and computer aided manufacture involved zirconia post and core / 北京大学学报(医学版)

ABSTRACT

Objective:To analyze the biomechanics trait of one-piece computer aided design and com-puter aided manufacture ( CAD/CAM ) zirconia post and core by the three-dimensional finite element . Methods:The three-dimensional finite element models of three upper central incisors restored with one -piece CAD/CAM zirconia post and core ( group 1 ) , refabricated zirconia post and hot-pressed porcelain core ( group 2 ) , and cast gold alloy post and core ( group 3 ) were built by geometry method respectively . 100 N vertical loading through the central incisor models long axis and 100 N loading along directing at an angle of 45°with the models long axis were used to imitate the central incisor stress state in biting and mandible physiological protraction movement .Results:Under vertical loading , the restored teeth without dentin ferrule, the maximum Von-Mises stress value of the tooth root in group 1 was the least(11.02 N), which was the largest (13.17 N)in group 2.The stress became weaker from the upper to the lower of the tooth root.The maximum Von-Mises stress value of the tooth root , post and core became smaller while the restored teeth with the 2.0 mm high dentin ferrule.Under directing at an angle of 45°loading, without the design of dentin ferrule in the restored teeth , the maximum Von-Mises stress value of the post and core in group 1 was the greatest(20.45 N), while that stress of post and core in group 3 was the smallest (13.61 N).With 2.0 mm high dentin ferrule design in the restored teeth , the tooth root stress became weaker.The maximum Von-Mises stress value of the tooth root was the greatest (14.10 N) in group 3, but which was the lowest (13.38 N) in group 1.Conclusion:The results of the three-dimensional finite element analysis infers that one-piece zirconia post and core restoration is more beneficial to disperse the bite force than the prefabricated zirconia post and the cast gold alloy post and core .The one-piece of zirconia post and core is good to protect the teeth and keep the restoration intact .