The research on the dental bridge model-making process based on the curing shrinkage epoxy and residual stress reduction

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.