Ehsan Homaei1, Xiao-Zhuang Jin2, Edmond Ho Nang Pow3, Jukka Pekka Matinlinna4, James Kit-Hon Tsoi5, Khalil Farhangdoost6. 1. Toos Dental Lab- Sahebkar, Mashhad, Iran; Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran; Dental Materials Science, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. Electronic address: ehsan.homaei@mail.um.ac.ir. 2. Dental Materials Science, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. Electronic address: xiaozuan@hku.hk. 3. Oral Rehabilitation, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. Electronic address: ehnpow@hku.hk. 4. Dental Materials Science, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. Electronic address: jpmat@hku.hk. 5. Dental Materials Science, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China. Electronic address: jkhtsoi@hku.hk. 6. Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran. Electronic address: farhang@um.ac.ir.
Abstract
OBJECTIVES: The purpose of this study was to estimate the fatigue life of premolars restored with two dental ceramics, lithium disilicate (LD) and polymer infiltrated ceramic (PIC) using the numerical method and compare it with the published in vitro data. METHODS: A premolar restored with full-coverage crown was digitized. The volumetric shape of tooth tissues and crowns were created in Mimics®. They were transferred to IA-FEMesh for mesh generation and the model was analyzed with Abaqus. By combining the stress distribution results with fatigue stress-life (S-N) approach, the lifetime of restored premolars was predicted. RESULTS: The predicted lifetime was 1,231,318 cycles for LD with fatigue load of 1400N, while the one for PIC was 475,063 cycles with the load of 870N. The peak value of maximum principal stress occurred at the contact area (LD: 172MPa and PIC: 96MPa) and central fossa (LD: 100MPa and PIC: 64MPa) for both ceramics which were the most seen failure areas in the experiment. In the adhesive layer, the maximum shear stress was observed at the shoulder area (LD: 53.6MPa and PIC: 29MPa). SIGNIFICANCE: The fatigue life and failure modes of all-ceramic crown determined by the numerical method seem to correlate well with the previous experimental study.
OBJECTIVES: The purpose of this study was to estimate the fatigue life of premolars restored with two dental ceramics, lithium disilicate (LD) and polymer infiltrated ceramic (PIC) using the numerical method and compare it with the published in vitro data. METHODS: A premolar restored with full-coverage crown was digitized. The volumetric shape of tooth tissues and crowns were created in Mimics®. They were transferred to IA-FEMesh for mesh generation and the model was analyzed with Abaqus. By combining the stress distribution results with fatigue stress-life (S-N) approach, the lifetime of restored premolars was predicted. RESULTS: The predicted lifetime was 1,231,318 cycles for LD with fatigue load of 1400N, while the one for PIC was 475,063 cycles with the load of 870N. The peak value of maximum principal stress occurred at the contact area (LD: 172MPa and PIC: 96MPa) and central fossa (LD: 100MPa and PIC: 64MPa) for both ceramics which were the most seen failure areas in the experiment. In the adhesive layer, the maximum shear stress was observed at the shoulder area (LD: 53.6MPa and PIC: 29MPa). SIGNIFICANCE: The fatigue life and failure modes of all-ceramic crown determined by the numerical method seem to correlate well with the previous experimental study.