Background/purpose The design of the connectors and implant abutments could affect the stress distribution of the tooth-implant supported prosthesis (TISP) entire system after loading. Therefore, the purpose of this study was to investigate the stress distribution of the TISP in different connectors and different implant abutments after loading. Materials and methods The TISP design used in this study was divided into six models. R1, R2 and R3 represented the tooth and the one-piece, two-piece and three-piece abutment implant system connected by a rigid connector, respectively, while NR1, NR2 and NR3 were the corresponding tooth-abutment implant systems connected by a non-rigid connector. A vertical occlusal load of 50 N was applied at a right angle on the 6 occlusal points of the occlusal surface. Results As a result, regarding the maximum average stress distribution, R1 and NR1 appeared on the implant fixture, and the other four models were on the implant abutment. On the other hand, regardless of the abutment implant system, the maximum von Mises stress generated by the rigid connector was greater than the corresponding non-rigid connector in the cortical bone around implant. In addition, the three-piece abutment implant system had lower von Mises stress than the one-piece and two-piece implant systems in the cortical bone. Conclusion It is concluded that by adding a flexible non-rigid connector and three-piece abutment device design to TISP, the occlusal load of the implant was dispersed, and the stress could be gradually introduced into the relatively strong implant abutment.

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Elderly people suffer from more and more teeth problems. The tooth-implant-supported prosthesis provides a reliable solution to missing teeth patients. The proper dental prosthesis design to prevent overstress is essential due to the mechanical characteristics of the dental bridge abutments are different. The finite element method is widely applied, but proper experimental validation is required. The curing shrinkage epoxy is applied for the photoelasticity measurement because its mechanical property is close to the cancellous bone. A series of process developments, including mold design, residual stress releasing and artificial soft film making, is accomplished in this research to simulate the mechanical response of dental bridges in practice. The process is proven and can be accomplished at the dentist's workshop. The transmission photoelasticity technique is applied to measure the residual stress distribution and it nondestructively provides the continuous improvement guideline. The model-making procedure and tools are proven to be available at the dental workshop. Following the model-making procedure, the dental bridge model shows a low residual stress level that the photoelasticity system cannot detect. Excellent reproducibility of the proposed procedure has been validated. These models exhibit stable maximum stress of 2.13 MPa around the natural tooth apex and apical implant region when a 300 N vertical loading is applied upon the dental bridge. Finally, a finite element model of the dental bridge, including the natural tooth and dental implant, is built and validated by the photoelastic measurement.