ANALYSIS OF STRESS ON TWO POSTS WITH DIFFERENT LUTING SYSTEMS – THREE DIMENSIONAL FINITE ELEMENT STUDY.

Aim:. The aim of this study was to investigate, by means of three-dimensional finite element analyses (3D-FEA), the influence of post materials and luting cements on stress distribution within posts, root dentin and their displacement under 100N identical perpendicular loading, Materials and Methods: A 3 mm section of endodontically treated canine tooth was scanned and reconstructed for 3-D modelling and Finite Element analysis(FEA). A ceramic post (CP) and a glass fibre post (GFP) were tested individually with four luting cements zinc phosphate (ZPH), glass ionomer (GI), resin modified glass ionomer (RMGI) and resin based cements (RC). A push-out test was conducted by subjecting all models to 100 N perpendicular loading at the post. Results: The maximum stresses generated along the CP-cement interface were significantly higher than corresponding stresses in the GFP-cement interface regardless of the cement type. GFP generated seven times higher stresses within theroot dentine than metal posts when ZPH and GI were used, and three times higher when RMGI and RC were used. The displacement of GFP was double (20µ) the displacement of CP (50µ) in all groups. Conclusions: The low elastic modulus of GFP generated lower stresses along its interface and higher stresses within the root dentine, therefore the probability of debonding and root fracture in the GFP group was lower.