The aim of this study was to investigate experimentally the fatigue and stability of three bar materials with distal extension at the molar region and to numerically analyse the biomechanical properties of the bar materials connected to overdentures in a patient individual model. A milled bar was designed for the mandible on fourimplants in the canine and second premolar region. Three bar materials were investigated: titanium (Ti), cobaltchromium (CoCr), and polyetherketonketon (PEKK). Firstly, static and fatigue tests were performed based on EN ISO 14801 in a commercial permanent loading set-up. Unilateral axial force was applied on the distal extension ofthe bars. Secondly, numerical models were created. Different bar materials and loading scenarios were analysed. The static fracture limit of the three materials was 1,750N, 780N, 310N for Ti, CoCr, and PEKK, respectively. The Wöhler curves showed comparable fatigue limits of 200N, 160N, and 150N for titanium, CoCr, and PEKK, respectively. The stress at the distal extension was 2,600MPa (Ti), 1,000MPa (CoCr), and 270MPa (PEKK). All loading simulations with the PEKK bar showed higher stresses in the implants and in the bone bed as well as higher displacements of the over denture in comparison to metal bars. PEKK showed different mechanical behaviour compared to Ti and CoCr. The distribution of stresses within the PEKK bar was wider than the area of loading which probably leads to fatigue of the whole bar and not only the part under load.