Photoelastic and finite element stress analysis reliability for implant-supported system stress investigation

Abstract

Aim: To compare the reliability between photoelastic and finite element (FE) analyses by evaluating the effect of different marginal misfit levels on the stresses generated on two different implant-supported systems using conventional and short implants. Methods: Two photoelastic models were obtained: model C with two conventional implants (4.1×11 mm); and model S with a conventional and a short implant (5×6 mm). Three-unit CoCr frameworks were fabricated simulating a superior first pre-molar (P) to first molar (M) fixed dental prosthesis. Different levels of misfit (µm) were selected based on the misfit average of 10 frameworks obtained by the single-screw test protocol: low (<20), medium (>20 and <40) and high (>40). Stress levels and distribution were measured by photoelastic analysis. A similar situation of the in vitro assay was designed and simulated by the in silico analysis. Maximum and minimum principal strain were recorded numerically and color-coded for the models. Von Mises Stress was obtained for the metallic components. Results: Photoelasticity and FE analyses showed similar tendency where the increase of misfit generates higher stress levels despite of the implant design. The short implant showed lower von Mises stress values; however, it presented stresses around its full length for the in vitro and in silico analysis. Also, model S showed higher µstrain values for all simulated misfit levels. The type of implant did not affect the stresses around pillar P. Conclusions: Photoelasticity and FEA are reliable methodologies presenting similarity for the investigation of the biomechanical behavior of implant-supported rehabilitations.

Interaction Phenomena between Dental Implants and Bone Tissue in Case of Misfit: A Pilot Study

“…Concerning multi-implant systems, misfit conditions can occur because the accuracy of the bar-manufacturing process is not always adequate for determining a perfect passive coupling between the bar and implants. Such misfit conditions can determine heavy stress in bone tissues and may compromise the reliability and durability of the prosthesis and the mandible bone health [11][12][13][14][15].…”

“…The elastic properties of bone vary with anatomic location and orientation, and the great variability of the mechanical properties is evident [37][38][39]. Cortical and trabecular bone have distinct characteristics, varying in dependence on the location considered [11,31,32]. In addition, the peri-implant bone properties change, depending on biological and biomolecular characteristics and especially during the healing phase [20,40].…”