Method: Four commercial brands were chosen for bi- dimensional tests (Araldite – Ciba Chemicals from Brazil); Flexible GIV - Polipox; Rigid GIV - Polipox and PL2 - (Measurements Group, Raleigh, NC, USA). Nine discs were manufactured. Four disks were fabricated from as-received resins and the other five disks were obtained from different mixture proportions between Flexible GIV (Polipox) and Rigid GIV (Polipox) resins. All models were subjected to diametrical compression test, and observed under circular polariscope. The first fringe observed was adopted as the benchmark to calculate the photo elastic constant and comparisons. The fotoelastic response of interest in this study was formation of sharp fringes, within the elastic regime of the material under load of 150 Newtons.
Result: : The resin Flexible GIV showed areas that fled the elastic regime. Residual stresses were observed for the resin PL2, and persistence of bubbles within the model. Resin GIV Rigid generated the first fringe order only at 280 Newtons load. Araldite resin behaved within the elastic regime and there were no areas with excessive concentration of fringes with 150 Newtons . The models generated from the mixing of resins GIV GIV Flexible And Rigid showed with non-homogeneous photoelastic images.
Conclusion: Among the four assessed brands, Araldite resin was the material that proved to be the most suitable for the manufacturing of models for teeth and/or implants photoelastic stress analyses.