Background: Patients who have lost one or more teeth will be rehabilitated by fixed partial dentures (FPD). The last decade shows interest in all-ceramic materials and polyetheretherketone (PEEK) as alternatives to metal FPD. The success of any FPD is strongly influenced by biomechanical factors,
therefore, it is important to evaluate the stresses in the structure and those transferred to the surrounding tissue, especially the connector area. The most popular technique for examining the effect of dental restoration materials on the stress distribution in fixed partial dentures is finite element analysis. Purpose: The study aimed to analyze the stress distribution and fracture resistance of zirconia and PEEK posterior FPD at different connector dimensions using finite element analysis. Material and Methods: Six 3D models of the FPD framework replaced the second premolar, first molar and second constructed on a computer (AutoCAD 2016 software) for simulation. Frameworks were constructed by connector dimensions of 9 mm2 , 12.25 mm2 and 16 mm2 , continue applied 600 N load axially on the centric fossa of pontic to analyze stress distribution and fracture resistance between zirconia and PEEK framework material. Results: Decrease in the value of stress concentration in connector dimension 9 mm2 ; 12,25 mm2 dan 16 mm2 zirconia (260.54 MPa, 209.53 MPa dan 149.38 MPa) to PEEK (247.14 MPa, 200.26 MPa and 144.49 MPa), and there is a difference in the maximum equivalent (von mises) stress of FPD posterior with connector dimension 9 mm2 , 12.25 mm2 and 16 mm2 of zirconia (260.54 MPa, 209.53 MPa and 149.38 MPa) to PEEK (247.14 MPa, 200.26 MPa and 144.49 MPa), meanwhile, the difference of maximum equivalent (elastic) strain [zirconia (0.0013, 0.0010 and 0.0007) and PEEK (0.0645, 0.0506 and 0.0373)] and total deformation [zirconia (0.0032 mm, 0.0031 mm and 0.0027 mm) and PEEK (0.1889 mm, 0.1624 mm and 0.1443 mm)] of PEEK posterior FPD were higher compare to zirconia. Conclusion: PEEK posterior FPD had higher fracture resistance compared to zirconia because it could reduce the stress concentration in the connector area.